clk: baikal-t1: Convert to platform device driver

[platform/kernel/linux-starfive.git] / drivers / gpu / drm / amd / amdkfd / kfd_svm.c

// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
 * Copyright 2020-2021 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include <linux/types.h>
#include <linux/sched/task.h>
#include "amdgpu_sync.h"
#include "amdgpu_object.h"
#include "amdgpu_vm.h"
#include "amdgpu_mn.h"
#include "amdgpu.h"
#include "amdgpu_xgmi.h"
#include "kfd_priv.h"
#include "kfd_svm.h"
#include "kfd_migrate.h"
#include "kfd_smi_events.h"

#ifdef dev_fmt
#undef dev_fmt
#endif
#define dev_fmt(fmt) "kfd_svm: %s: " fmt, __func__

#define AMDGPU_SVM_RANGE_RESTORE_DELAY_MS 1

/* Long enough to ensure no retry fault comes after svm range is restored and
 * page table is updated.
 */
#define AMDGPU_SVM_RANGE_RETRY_FAULT_PENDING    (2UL * NSEC_PER_MSEC)

/* Giant svm range split into smaller ranges based on this, it is decided using
 * minimum of all dGPU/APU 1/32 VRAM size, between 2MB to 1GB and alignment to
 * power of 2MB.
 */
static uint64_t max_svm_range_pages;

struct criu_svm_metadata {
        struct list_head list;
        struct kfd_criu_svm_range_priv_data data;
};

static void svm_range_evict_svm_bo_worker(struct work_struct *work);
static bool
svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni,
                                    const struct mmu_notifier_range *range,
                                    unsigned long cur_seq);
static int
svm_range_check_vm(struct kfd_process *p, uint64_t start, uint64_t last,
                   uint64_t *bo_s, uint64_t *bo_l);
static const struct mmu_interval_notifier_ops svm_range_mn_ops = {
        .invalidate = svm_range_cpu_invalidate_pagetables,
};

/**
 * svm_range_unlink - unlink svm_range from lists and interval tree
 * @prange: svm range structure to be removed
 *
 * Remove the svm_range from the svms and svm_bo lists and the svms
 * interval tree.
 *
 * Context: The caller must hold svms->lock
 */
static void svm_range_unlink(struct svm_range *prange)
{
        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms,
                 prange, prange->start, prange->last);

        if (prange->svm_bo) {
                spin_lock(&prange->svm_bo->list_lock);
                list_del(&prange->svm_bo_list);
                spin_unlock(&prange->svm_bo->list_lock);
        }

        list_del(&prange->list);
        if (prange->it_node.start != 0 && prange->it_node.last != 0)
                interval_tree_remove(&prange->it_node, &prange->svms->objects);
}

static void
svm_range_add_notifier_locked(struct mm_struct *mm, struct svm_range *prange)
{
        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms,
                 prange, prange->start, prange->last);

        mmu_interval_notifier_insert_locked(&prange->notifier, mm,
                                     prange->start << PAGE_SHIFT,
                                     prange->npages << PAGE_SHIFT,
                                     &svm_range_mn_ops);
}

/**
 * svm_range_add_to_svms - add svm range to svms
 * @prange: svm range structure to be added
 *
 * Add the svm range to svms interval tree and link list
 *
 * Context: The caller must hold svms->lock
 */
static void svm_range_add_to_svms(struct svm_range *prange)
{
        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms,
                 prange, prange->start, prange->last);

        list_move_tail(&prange->list, &prange->svms->list);
        prange->it_node.start = prange->start;
        prange->it_node.last = prange->last;
        interval_tree_insert(&prange->it_node, &prange->svms->objects);
}

static void svm_range_remove_notifier(struct svm_range *prange)
{
        pr_debug("remove notifier svms 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                 prange->svms, prange,
                 prange->notifier.interval_tree.start >> PAGE_SHIFT,
                 prange->notifier.interval_tree.last >> PAGE_SHIFT);

        if (prange->notifier.interval_tree.start != 0 &&
            prange->notifier.interval_tree.last != 0)
                mmu_interval_notifier_remove(&prange->notifier);
}

static bool
svm_is_valid_dma_mapping_addr(struct device *dev, dma_addr_t dma_addr)
{
        return dma_addr && !dma_mapping_error(dev, dma_addr) &&
               !(dma_addr & SVM_RANGE_VRAM_DOMAIN);
}

static int
svm_range_dma_map_dev(struct amdgpu_device *adev, struct svm_range *prange,
                      unsigned long offset, unsigned long npages,
                      unsigned long *hmm_pfns, uint32_t gpuidx)
{
        enum dma_data_direction dir = DMA_BIDIRECTIONAL;
        dma_addr_t *addr = prange->dma_addr[gpuidx];
        struct device *dev = adev->dev;
        struct page *page;
        int i, r;

        if (!addr) {
                addr = kvcalloc(prange->npages, sizeof(*addr), GFP_KERNEL);
                if (!addr)
                        return -ENOMEM;
                prange->dma_addr[gpuidx] = addr;
        }

        addr += offset;
        for (i = 0; i < npages; i++) {
                if (svm_is_valid_dma_mapping_addr(dev, addr[i]))
                        dma_unmap_page(dev, addr[i], PAGE_SIZE, dir);

                page = hmm_pfn_to_page(hmm_pfns[i]);
                if (is_zone_device_page(page)) {
                        struct amdgpu_device *bo_adev =
                                        amdgpu_ttm_adev(prange->svm_bo->bo->tbo.bdev);

                        addr[i] = (hmm_pfns[i] << PAGE_SHIFT) +
                                   bo_adev->vm_manager.vram_base_offset -
                                   bo_adev->kfd.dev->pgmap.range.start;
                        addr[i] |= SVM_RANGE_VRAM_DOMAIN;
                        pr_debug_ratelimited("vram address: 0x%llx\n", addr[i]);
                        continue;
                }
                addr[i] = dma_map_page(dev, page, 0, PAGE_SIZE, dir);
                r = dma_mapping_error(dev, addr[i]);
                if (r) {
                        dev_err(dev, "failed %d dma_map_page\n", r);
                        return r;
                }
                pr_debug_ratelimited("dma mapping 0x%llx for page addr 0x%lx\n",
                                     addr[i] >> PAGE_SHIFT, page_to_pfn(page));
        }
        return 0;
}

static int
svm_range_dma_map(struct svm_range *prange, unsigned long *bitmap,
                  unsigned long offset, unsigned long npages,
                  unsigned long *hmm_pfns)
{
        struct kfd_process *p;
        uint32_t gpuidx;
        int r;

        p = container_of(prange->svms, struct kfd_process, svms);

        for_each_set_bit(gpuidx, bitmap, MAX_GPU_INSTANCE) {
                struct kfd_process_device *pdd;

                pr_debug("mapping to gpu idx 0x%x\n", gpuidx);
                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        return -EINVAL;
                }

                r = svm_range_dma_map_dev(pdd->dev->adev, prange, offset, npages,
                                          hmm_pfns, gpuidx);
                if (r)
                        break;
        }

        return r;
}

void svm_range_dma_unmap(struct device *dev, dma_addr_t *dma_addr,
                         unsigned long offset, unsigned long npages)
{
        enum dma_data_direction dir = DMA_BIDIRECTIONAL;
        int i;

        if (!dma_addr)
                return;

        for (i = offset; i < offset + npages; i++) {
                if (!svm_is_valid_dma_mapping_addr(dev, dma_addr[i]))
                        continue;
                pr_debug_ratelimited("unmap 0x%llx\n", dma_addr[i] >> PAGE_SHIFT);
                dma_unmap_page(dev, dma_addr[i], PAGE_SIZE, dir);
                dma_addr[i] = 0;
        }
}

void svm_range_free_dma_mappings(struct svm_range *prange)
{
        struct kfd_process_device *pdd;
        dma_addr_t *dma_addr;
        struct device *dev;
        struct kfd_process *p;
        uint32_t gpuidx;

        p = container_of(prange->svms, struct kfd_process, svms);

        for (gpuidx = 0; gpuidx < MAX_GPU_INSTANCE; gpuidx++) {
                dma_addr = prange->dma_addr[gpuidx];
                if (!dma_addr)
                        continue;

                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        continue;
                }
                dev = &pdd->dev->pdev->dev;
                svm_range_dma_unmap(dev, dma_addr, 0, prange->npages);
                kvfree(dma_addr);
                prange->dma_addr[gpuidx] = NULL;
        }
}

static void svm_range_free(struct svm_range *prange, bool update_mem_usage)
{
        uint64_t size = (prange->last - prange->start + 1) << PAGE_SHIFT;
        struct kfd_process *p = container_of(prange->svms, struct kfd_process, svms);

        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms, prange,
                 prange->start, prange->last);

        svm_range_vram_node_free(prange);
        svm_range_free_dma_mappings(prange);

        if (update_mem_usage && !p->xnack_enabled) {
                pr_debug("unreserve mem limit: %lld\n", size);
                amdgpu_amdkfd_unreserve_mem_limit(NULL, size,
                                        KFD_IOC_ALLOC_MEM_FLAGS_USERPTR);
        }
        mutex_destroy(&prange->lock);
        mutex_destroy(&prange->migrate_mutex);
        kfree(prange);
}

static void
svm_range_set_default_attributes(int32_t *location, int32_t *prefetch_loc,
                                 uint8_t *granularity, uint32_t *flags)
{
        *location = KFD_IOCTL_SVM_LOCATION_UNDEFINED;
        *prefetch_loc = KFD_IOCTL_SVM_LOCATION_UNDEFINED;
        *granularity = 9;
        *flags =
                KFD_IOCTL_SVM_FLAG_HOST_ACCESS | KFD_IOCTL_SVM_FLAG_COHERENT;
}

static struct
svm_range *svm_range_new(struct svm_range_list *svms, uint64_t start,
                         uint64_t last, bool update_mem_usage)
{
        uint64_t size = last - start + 1;
        struct svm_range *prange;
        struct kfd_process *p;

        prange = kzalloc(sizeof(*prange), GFP_KERNEL);
        if (!prange)
                return NULL;

        p = container_of(svms, struct kfd_process, svms);
        if (!p->xnack_enabled && update_mem_usage &&
            amdgpu_amdkfd_reserve_mem_limit(NULL, size << PAGE_SHIFT,
                                            KFD_IOC_ALLOC_MEM_FLAGS_USERPTR)) {
                pr_info("SVM mapping failed, exceeds resident system memory limit\n");
                kfree(prange);
                return NULL;
        }
        prange->npages = size;
        prange->svms = svms;
        prange->start = start;
        prange->last = last;
        INIT_LIST_HEAD(&prange->list);
        INIT_LIST_HEAD(&prange->update_list);
        INIT_LIST_HEAD(&prange->svm_bo_list);
        INIT_LIST_HEAD(&prange->deferred_list);
        INIT_LIST_HEAD(&prange->child_list);
        atomic_set(&prange->invalid, 0);
        prange->validate_timestamp = 0;
        mutex_init(&prange->migrate_mutex);
        mutex_init(&prange->lock);

        if (p->xnack_enabled)
                bitmap_copy(prange->bitmap_access, svms->bitmap_supported,
                            MAX_GPU_INSTANCE);

        svm_range_set_default_attributes(&prange->preferred_loc,
                                         &prange->prefetch_loc,
                                         &prange->granularity, &prange->flags);

        pr_debug("svms 0x%p [0x%llx 0x%llx]\n", svms, start, last);

        return prange;
}

static bool svm_bo_ref_unless_zero(struct svm_range_bo *svm_bo)
{
        if (!svm_bo || !kref_get_unless_zero(&svm_bo->kref))
                return false;

        return true;
}

static void svm_range_bo_release(struct kref *kref)
{
        struct svm_range_bo *svm_bo;

        svm_bo = container_of(kref, struct svm_range_bo, kref);
        pr_debug("svm_bo 0x%p\n", svm_bo);

        spin_lock(&svm_bo->list_lock);
        while (!list_empty(&svm_bo->range_list)) {
                struct svm_range *prange =
                                list_first_entry(&svm_bo->range_list,
                                                struct svm_range, svm_bo_list);
                /* list_del_init tells a concurrent svm_range_vram_node_new when
                 * it's safe to reuse the svm_bo pointer and svm_bo_list head.
                 */
                list_del_init(&prange->svm_bo_list);
                spin_unlock(&svm_bo->list_lock);

                pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms,
                         prange->start, prange->last);
                mutex_lock(&prange->lock);
                prange->svm_bo = NULL;
                mutex_unlock(&prange->lock);

                spin_lock(&svm_bo->list_lock);
        }
        spin_unlock(&svm_bo->list_lock);
        if (!dma_fence_is_signaled(&svm_bo->eviction_fence->base)) {
                /* We're not in the eviction worker.
                 * Signal the fence and synchronize with any
                 * pending eviction work.
                 */
                dma_fence_signal(&svm_bo->eviction_fence->base);
                cancel_work_sync(&svm_bo->eviction_work);
        }
        dma_fence_put(&svm_bo->eviction_fence->base);
        amdgpu_bo_unref(&svm_bo->bo);
        kfree(svm_bo);
}

static void svm_range_bo_wq_release(struct work_struct *work)
{
        struct svm_range_bo *svm_bo;

        svm_bo = container_of(work, struct svm_range_bo, release_work);
        svm_range_bo_release(&svm_bo->kref);
}

static void svm_range_bo_release_async(struct kref *kref)
{
        struct svm_range_bo *svm_bo;

        svm_bo = container_of(kref, struct svm_range_bo, kref);
        pr_debug("svm_bo 0x%p\n", svm_bo);
        INIT_WORK(&svm_bo->release_work, svm_range_bo_wq_release);
        schedule_work(&svm_bo->release_work);
}

void svm_range_bo_unref_async(struct svm_range_bo *svm_bo)
{
        kref_put(&svm_bo->kref, svm_range_bo_release_async);
}

static void svm_range_bo_unref(struct svm_range_bo *svm_bo)
{
        if (svm_bo)
                kref_put(&svm_bo->kref, svm_range_bo_release);
}

static bool
svm_range_validate_svm_bo(struct amdgpu_device *adev, struct svm_range *prange)
{
        struct amdgpu_device *bo_adev;

        mutex_lock(&prange->lock);
        if (!prange->svm_bo) {
                mutex_unlock(&prange->lock);
                return false;
        }
        if (prange->ttm_res) {
                /* We still have a reference, all is well */
                mutex_unlock(&prange->lock);
                return true;
        }
        if (svm_bo_ref_unless_zero(prange->svm_bo)) {
                /*
                 * Migrate from GPU to GPU, remove range from source bo_adev
                 * svm_bo range list, and return false to allocate svm_bo from
                 * destination adev.
                 */
                bo_adev = amdgpu_ttm_adev(prange->svm_bo->bo->tbo.bdev);
                if (bo_adev != adev) {
                        mutex_unlock(&prange->lock);

                        spin_lock(&prange->svm_bo->list_lock);
                        list_del_init(&prange->svm_bo_list);
                        spin_unlock(&prange->svm_bo->list_lock);

                        svm_range_bo_unref(prange->svm_bo);
                        return false;
                }
                if (READ_ONCE(prange->svm_bo->evicting)) {
                        struct dma_fence *f;
                        struct svm_range_bo *svm_bo;
                        /* The BO is getting evicted,
                         * we need to get a new one
                         */
                        mutex_unlock(&prange->lock);
                        svm_bo = prange->svm_bo;
                        f = dma_fence_get(&svm_bo->eviction_fence->base);
                        svm_range_bo_unref(prange->svm_bo);
                        /* wait for the fence to avoid long spin-loop
                         * at list_empty_careful
                         */
                        dma_fence_wait(f, false);
                        dma_fence_put(f);
                } else {
                        /* The BO was still around and we got
                         * a new reference to it
                         */
                        mutex_unlock(&prange->lock);
                        pr_debug("reuse old bo svms 0x%p [0x%lx 0x%lx]\n",
                                 prange->svms, prange->start, prange->last);

                        prange->ttm_res = prange->svm_bo->bo->tbo.resource;
                        return true;
                }

        } else {
                mutex_unlock(&prange->lock);
        }

        /* We need a new svm_bo. Spin-loop to wait for concurrent
         * svm_range_bo_release to finish removing this range from
         * its range list. After this, it is safe to reuse the
         * svm_bo pointer and svm_bo_list head.
         */
        while (!list_empty_careful(&prange->svm_bo_list))
                ;

        return false;
}

static struct svm_range_bo *svm_range_bo_new(void)
{
        struct svm_range_bo *svm_bo;

        svm_bo = kzalloc(sizeof(*svm_bo), GFP_KERNEL);
        if (!svm_bo)
                return NULL;

        kref_init(&svm_bo->kref);
        INIT_LIST_HEAD(&svm_bo->range_list);
        spin_lock_init(&svm_bo->list_lock);

        return svm_bo;
}

int
svm_range_vram_node_new(struct amdgpu_device *adev, struct svm_range *prange,
                        bool clear)
{
        struct amdgpu_bo_param bp;
        struct svm_range_bo *svm_bo;
        struct amdgpu_bo_user *ubo;
        struct amdgpu_bo *bo;
        struct kfd_process *p;
        struct mm_struct *mm;
        int r;

        p = container_of(prange->svms, struct kfd_process, svms);
        pr_debug("pasid: %x svms 0x%p [0x%lx 0x%lx]\n", p->pasid, prange->svms,
                 prange->start, prange->last);

        if (svm_range_validate_svm_bo(adev, prange))
                return 0;

        svm_bo = svm_range_bo_new();
        if (!svm_bo) {
                pr_debug("failed to alloc svm bo\n");
                return -ENOMEM;
        }
        mm = get_task_mm(p->lead_thread);
        if (!mm) {
                pr_debug("failed to get mm\n");
                kfree(svm_bo);
                return -ESRCH;
        }
        svm_bo->svms = prange->svms;
        svm_bo->eviction_fence =
                amdgpu_amdkfd_fence_create(dma_fence_context_alloc(1),
                                           mm,
                                           svm_bo);
        mmput(mm);
        INIT_WORK(&svm_bo->eviction_work, svm_range_evict_svm_bo_worker);
        svm_bo->evicting = 0;
        memset(&bp, 0, sizeof(bp));
        bp.size = prange->npages * PAGE_SIZE;
        bp.byte_align = PAGE_SIZE;
        bp.domain = AMDGPU_GEM_DOMAIN_VRAM;
        bp.flags = AMDGPU_GEM_CREATE_NO_CPU_ACCESS;
        bp.flags |= clear ? AMDGPU_GEM_CREATE_VRAM_CLEARED : 0;
        bp.flags |= AMDGPU_GEM_CREATE_DISCARDABLE;
        bp.type = ttm_bo_type_device;
        bp.resv = NULL;

        r = amdgpu_bo_create_user(adev, &bp, &ubo);
        if (r) {
                pr_debug("failed %d to create bo\n", r);
                goto create_bo_failed;
        }
        bo = &ubo->bo;
        r = amdgpu_bo_reserve(bo, true);
        if (r) {
                pr_debug("failed %d to reserve bo\n", r);
                goto reserve_bo_failed;
        }

        r = dma_resv_reserve_fences(bo->tbo.base.resv, 1);
        if (r) {
                pr_debug("failed %d to reserve bo\n", r);
                amdgpu_bo_unreserve(bo);
                goto reserve_bo_failed;
        }
        amdgpu_bo_fence(bo, &svm_bo->eviction_fence->base, true);

        amdgpu_bo_unreserve(bo);

        svm_bo->bo = bo;
        prange->svm_bo = svm_bo;
        prange->ttm_res = bo->tbo.resource;
        prange->offset = 0;

        spin_lock(&svm_bo->list_lock);
        list_add(&prange->svm_bo_list, &svm_bo->range_list);
        spin_unlock(&svm_bo->list_lock);

        return 0;

reserve_bo_failed:
        amdgpu_bo_unref(&bo);
create_bo_failed:
        dma_fence_put(&svm_bo->eviction_fence->base);
        kfree(svm_bo);
        prange->ttm_res = NULL;

        return r;
}

void svm_range_vram_node_free(struct svm_range *prange)
{
        svm_range_bo_unref(prange->svm_bo);
        prange->ttm_res = NULL;
}

struct amdgpu_device *
svm_range_get_adev_by_id(struct svm_range *prange, uint32_t gpu_id)
{
        struct kfd_process_device *pdd;
        struct kfd_process *p;
        int32_t gpu_idx;

        p = container_of(prange->svms, struct kfd_process, svms);

        gpu_idx = kfd_process_gpuidx_from_gpuid(p, gpu_id);
        if (gpu_idx < 0) {
                pr_debug("failed to get device by id 0x%x\n", gpu_id);
                return NULL;
        }
        pdd = kfd_process_device_from_gpuidx(p, gpu_idx);
        if (!pdd) {
                pr_debug("failed to get device by idx 0x%x\n", gpu_idx);
                return NULL;
        }

        return pdd->dev->adev;
}

struct kfd_process_device *
svm_range_get_pdd_by_adev(struct svm_range *prange, struct amdgpu_device *adev)
{
        struct kfd_process *p;
        int32_t gpu_idx, gpuid;
        int r;

        p = container_of(prange->svms, struct kfd_process, svms);

        r = kfd_process_gpuid_from_adev(p, adev, &gpuid, &gpu_idx);
        if (r) {
                pr_debug("failed to get device id by adev %p\n", adev);
                return NULL;
        }

        return kfd_process_device_from_gpuidx(p, gpu_idx);
}

static int svm_range_bo_validate(void *param, struct amdgpu_bo *bo)
{
        struct ttm_operation_ctx ctx = { false, false };

        amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_VRAM);

        return ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
}

static int
svm_range_check_attr(struct kfd_process *p,
                     uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs)
{
        uint32_t i;

        for (i = 0; i < nattr; i++) {
                uint32_t val = attrs[i].value;
                int gpuidx = MAX_GPU_INSTANCE;

                switch (attrs[i].type) {
                case KFD_IOCTL_SVM_ATTR_PREFERRED_LOC:
                        if (val != KFD_IOCTL_SVM_LOCATION_SYSMEM &&
                            val != KFD_IOCTL_SVM_LOCATION_UNDEFINED)
                                gpuidx = kfd_process_gpuidx_from_gpuid(p, val);
                        break;
                case KFD_IOCTL_SVM_ATTR_PREFETCH_LOC:
                        if (val != KFD_IOCTL_SVM_LOCATION_SYSMEM)
                                gpuidx = kfd_process_gpuidx_from_gpuid(p, val);
                        break;
                case KFD_IOCTL_SVM_ATTR_ACCESS:
                case KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE:
                case KFD_IOCTL_SVM_ATTR_NO_ACCESS:
                        gpuidx = kfd_process_gpuidx_from_gpuid(p, val);
                        break;
                case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
                        break;
                case KFD_IOCTL_SVM_ATTR_CLR_FLAGS:
                        break;
                case KFD_IOCTL_SVM_ATTR_GRANULARITY:
                        break;
                default:
                        pr_debug("unknown attr type 0x%x\n", attrs[i].type);
                        return -EINVAL;
                }

                if (gpuidx < 0) {
                        pr_debug("no GPU 0x%x found\n", val);
                        return -EINVAL;
                } else if (gpuidx < MAX_GPU_INSTANCE &&
                           !test_bit(gpuidx, p->svms.bitmap_supported)) {
                        pr_debug("GPU 0x%x not supported\n", val);
                        return -EINVAL;
                }
        }

        return 0;
}

static void
svm_range_apply_attrs(struct kfd_process *p, struct svm_range *prange,
                      uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs,
                      bool *update_mapping)
{
        uint32_t i;
        int gpuidx;

        for (i = 0; i < nattr; i++) {
                switch (attrs[i].type) {
                case KFD_IOCTL_SVM_ATTR_PREFERRED_LOC:
                        prange->preferred_loc = attrs[i].value;
                        break;
                case KFD_IOCTL_SVM_ATTR_PREFETCH_LOC:
                        prange->prefetch_loc = attrs[i].value;
                        break;
                case KFD_IOCTL_SVM_ATTR_ACCESS:
                case KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE:
                case KFD_IOCTL_SVM_ATTR_NO_ACCESS:
                        *update_mapping = true;
                        gpuidx = kfd_process_gpuidx_from_gpuid(p,
                                                               attrs[i].value);
                        if (attrs[i].type == KFD_IOCTL_SVM_ATTR_NO_ACCESS) {
                                bitmap_clear(prange->bitmap_access, gpuidx, 1);
                                bitmap_clear(prange->bitmap_aip, gpuidx, 1);
                        } else if (attrs[i].type == KFD_IOCTL_SVM_ATTR_ACCESS) {
                                bitmap_set(prange->bitmap_access, gpuidx, 1);
                                bitmap_clear(prange->bitmap_aip, gpuidx, 1);
                        } else {
                                bitmap_clear(prange->bitmap_access, gpuidx, 1);
                                bitmap_set(prange->bitmap_aip, gpuidx, 1);
                        }
                        break;
                case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
                        *update_mapping = true;
                        prange->flags |= attrs[i].value;
                        break;
                case KFD_IOCTL_SVM_ATTR_CLR_FLAGS:
                        *update_mapping = true;
                        prange->flags &= ~attrs[i].value;
                        break;
                case KFD_IOCTL_SVM_ATTR_GRANULARITY:
                        prange->granularity = attrs[i].value;
                        break;
                default:
                        WARN_ONCE(1, "svm_range_check_attrs wasn't called?");
                }
        }
}

static bool
svm_range_is_same_attrs(struct kfd_process *p, struct svm_range *prange,
                        uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs)
{
        uint32_t i;
        int gpuidx;

        for (i = 0; i < nattr; i++) {
                switch (attrs[i].type) {
                case KFD_IOCTL_SVM_ATTR_PREFERRED_LOC:
                        if (prange->preferred_loc != attrs[i].value)
                                return false;
                        break;
                case KFD_IOCTL_SVM_ATTR_PREFETCH_LOC:
                        /* Prefetch should always trigger a migration even
                         * if the value of the attribute didn't change.
                         */
                        return false;
                case KFD_IOCTL_SVM_ATTR_ACCESS:
                case KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE:
                case KFD_IOCTL_SVM_ATTR_NO_ACCESS:
                        gpuidx = kfd_process_gpuidx_from_gpuid(p,
                                                               attrs[i].value);
                        if (attrs[i].type == KFD_IOCTL_SVM_ATTR_NO_ACCESS) {
                                if (test_bit(gpuidx, prange->bitmap_access) ||
                                    test_bit(gpuidx, prange->bitmap_aip))
                                        return false;
                        } else if (attrs[i].type == KFD_IOCTL_SVM_ATTR_ACCESS) {
                                if (!test_bit(gpuidx, prange->bitmap_access))
                                        return false;
                        } else {
                                if (!test_bit(gpuidx, prange->bitmap_aip))
                                        return false;
                        }
                        break;
                case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
                        if ((prange->flags & attrs[i].value) != attrs[i].value)
                                return false;
                        break;
                case KFD_IOCTL_SVM_ATTR_CLR_FLAGS:
                        if ((prange->flags & attrs[i].value) != 0)
                                return false;
                        break;
                case KFD_IOCTL_SVM_ATTR_GRANULARITY:
                        if (prange->granularity != attrs[i].value)
                                return false;
                        break;
                default:
                        WARN_ONCE(1, "svm_range_check_attrs wasn't called?");
                }
        }

        return true;
}

/**
 * svm_range_debug_dump - print all range information from svms
 * @svms: svm range list header
 *
 * debug output svm range start, end, prefetch location from svms
 * interval tree and link list
 *
 * Context: The caller must hold svms->lock
 */
static void svm_range_debug_dump(struct svm_range_list *svms)
{
        struct interval_tree_node *node;
        struct svm_range *prange;

        pr_debug("dump svms 0x%p list\n", svms);
        pr_debug("range\tstart\tpage\tend\t\tlocation\n");

        list_for_each_entry(prange, &svms->list, list) {
                pr_debug("0x%p 0x%lx\t0x%llx\t0x%llx\t0x%x\n",
                         prange, prange->start, prange->npages,
                         prange->start + prange->npages - 1,
                         prange->actual_loc);
        }

        pr_debug("dump svms 0x%p interval tree\n", svms);
        pr_debug("range\tstart\tpage\tend\t\tlocation\n");
        node = interval_tree_iter_first(&svms->objects, 0, ~0ULL);
        while (node) {
                prange = container_of(node, struct svm_range, it_node);
                pr_debug("0x%p 0x%lx\t0x%llx\t0x%llx\t0x%x\n",
                         prange, prange->start, prange->npages,
                         prange->start + prange->npages - 1,
                         prange->actual_loc);
                node = interval_tree_iter_next(node, 0, ~0ULL);
        }
}

static int
svm_range_split_array(void *ppnew, void *ppold, size_t size,
                      uint64_t old_start, uint64_t old_n,
                      uint64_t new_start, uint64_t new_n)
{
        unsigned char *new, *old, *pold;
        uint64_t d;

        if (!ppold)
                return 0;
        pold = *(unsigned char **)ppold;
        if (!pold)
                return 0;

        new = kvmalloc_array(new_n, size, GFP_KERNEL);
        if (!new)
                return -ENOMEM;

        d = (new_start - old_start) * size;
        memcpy(new, pold + d, new_n * size);

        old = kvmalloc_array(old_n, size, GFP_KERNEL);
        if (!old) {
                kvfree(new);
                return -ENOMEM;
        }

        d = (new_start == old_start) ? new_n * size : 0;
        memcpy(old, pold + d, old_n * size);

        kvfree(pold);
        *(void **)ppold = old;
        *(void **)ppnew = new;

        return 0;
}

static int
svm_range_split_pages(struct svm_range *new, struct svm_range *old,
                      uint64_t start, uint64_t last)
{
        uint64_t npages = last - start + 1;
        int i, r;

        for (i = 0; i < MAX_GPU_INSTANCE; i++) {
                r = svm_range_split_array(&new->dma_addr[i], &old->dma_addr[i],
                                          sizeof(*old->dma_addr[i]), old->start,
                                          npages, new->start, new->npages);
                if (r)
                        return r;
        }

        return 0;
}

static int
svm_range_split_nodes(struct svm_range *new, struct svm_range *old,
                      uint64_t start, uint64_t last)
{
        uint64_t npages = last - start + 1;

        pr_debug("svms 0x%p new prange 0x%p start 0x%lx [0x%llx 0x%llx]\n",
                 new->svms, new, new->start, start, last);

        if (new->start == old->start) {
                new->offset = old->offset;
                old->offset += new->npages;
        } else {
                new->offset = old->offset + npages;
        }

        new->svm_bo = svm_range_bo_ref(old->svm_bo);
        new->ttm_res = old->ttm_res;

        spin_lock(&new->svm_bo->list_lock);
        list_add(&new->svm_bo_list, &new->svm_bo->range_list);
        spin_unlock(&new->svm_bo->list_lock);

        return 0;
}

/**
 * svm_range_split_adjust - split range and adjust
 *
 * @new: new range
 * @old: the old range
 * @start: the old range adjust to start address in pages
 * @last: the old range adjust to last address in pages
 *
 * Copy system memory dma_addr or vram ttm_res in old range to new
 * range from new_start up to size new->npages, the remaining old range is from
 * start to last
 *
 * Return:
 * 0 - OK, -ENOMEM - out of memory
 */
static int
svm_range_split_adjust(struct svm_range *new, struct svm_range *old,
                      uint64_t start, uint64_t last)
{
        int r;

        pr_debug("svms 0x%p new 0x%lx old [0x%lx 0x%lx] => [0x%llx 0x%llx]\n",
                 new->svms, new->start, old->start, old->last, start, last);

        if (new->start < old->start ||
            new->last > old->last) {
                WARN_ONCE(1, "invalid new range start or last\n");
                return -EINVAL;
        }

        r = svm_range_split_pages(new, old, start, last);
        if (r)
                return r;

        if (old->actual_loc && old->ttm_res) {
                r = svm_range_split_nodes(new, old, start, last);
                if (r)
                        return r;
        }

        old->npages = last - start + 1;
        old->start = start;
        old->last = last;
        new->flags = old->flags;
        new->preferred_loc = old->preferred_loc;
        new->prefetch_loc = old->prefetch_loc;
        new->actual_loc = old->actual_loc;
        new->granularity = old->granularity;
        new->mapped_to_gpu = old->mapped_to_gpu;
        bitmap_copy(new->bitmap_access, old->bitmap_access, MAX_GPU_INSTANCE);
        bitmap_copy(new->bitmap_aip, old->bitmap_aip, MAX_GPU_INSTANCE);

        return 0;
}

/**
 * svm_range_split - split a range in 2 ranges
 *
 * @prange: the svm range to split
 * @start: the remaining range start address in pages
 * @last: the remaining range last address in pages
 * @new: the result new range generated
 *
 * Two cases only:
 * case 1: if start == prange->start
 *         prange ==> prange[start, last]
 *         new range [last + 1, prange->last]
 *
 * case 2: if last == prange->last
 *         prange ==> prange[start, last]
 *         new range [prange->start, start - 1]
 *
 * Return:
 * 0 - OK, -ENOMEM - out of memory, -EINVAL - invalid start, last
 */
static int
svm_range_split(struct svm_range *prange, uint64_t start, uint64_t last,
                struct svm_range **new)
{
        uint64_t old_start = prange->start;
        uint64_t old_last = prange->last;
        struct svm_range_list *svms;
        int r = 0;

        pr_debug("svms 0x%p [0x%llx 0x%llx] to [0x%llx 0x%llx]\n", prange->svms,
                 old_start, old_last, start, last);

        if (old_start != start && old_last != last)
                return -EINVAL;
        if (start < old_start || last > old_last)
                return -EINVAL;

        svms = prange->svms;
        if (old_start == start)
                *new = svm_range_new(svms, last + 1, old_last, false);
        else
                *new = svm_range_new(svms, old_start, start - 1, false);
        if (!*new)
                return -ENOMEM;

        r = svm_range_split_adjust(*new, prange, start, last);
        if (r) {
                pr_debug("failed %d split [0x%llx 0x%llx] to [0x%llx 0x%llx]\n",
                         r, old_start, old_last, start, last);
                svm_range_free(*new, false);
                *new = NULL;
        }

        return r;
}

static int
svm_range_split_tail(struct svm_range *prange,
                     uint64_t new_last, struct list_head *insert_list)
{
        struct svm_range *tail;
        int r = svm_range_split(prange, prange->start, new_last, &tail);

        if (!r)
                list_add(&tail->list, insert_list);
        return r;
}

static int
svm_range_split_head(struct svm_range *prange,
                     uint64_t new_start, struct list_head *insert_list)
{
        struct svm_range *head;
        int r = svm_range_split(prange, new_start, prange->last, &head);

        if (!r)
                list_add(&head->list, insert_list);
        return r;
}

static void
svm_range_add_child(struct svm_range *prange, struct mm_struct *mm,
                    struct svm_range *pchild, enum svm_work_list_ops op)
{
        pr_debug("add child 0x%p [0x%lx 0x%lx] to prange 0x%p child list %d\n",
                 pchild, pchild->start, pchild->last, prange, op);

        pchild->work_item.mm = mm;
        pchild->work_item.op = op;
        list_add_tail(&pchild->child_list, &prange->child_list);
}

/**
 * svm_range_split_by_granularity - collect ranges within granularity boundary
 *
 * @p: the process with svms list
 * @mm: mm structure
 * @addr: the vm fault address in pages, to split the prange
 * @parent: parent range if prange is from child list
 * @prange: prange to split
 *
 * Trims @prange to be a single aligned block of prange->granularity if
 * possible. The head and tail are added to the child_list in @parent.
 *
 * Context: caller must hold mmap_read_lock and prange->lock
 *
 * Return:
 * 0 - OK, otherwise error code
 */
int
svm_range_split_by_granularity(struct kfd_process *p, struct mm_struct *mm,
                               unsigned long addr, struct svm_range *parent,
                               struct svm_range *prange)
{
        struct svm_range *head, *tail;
        unsigned long start, last, size;
        int r;

        /* Align splited range start and size to granularity size, then a single
         * PTE will be used for whole range, this reduces the number of PTE
         * updated and the L1 TLB space used for translation.
         */
        size = 1UL << prange->granularity;
        start = ALIGN_DOWN(addr, size);
        last = ALIGN(addr + 1, size) - 1;

        pr_debug("svms 0x%p split [0x%lx 0x%lx] to [0x%lx 0x%lx] size 0x%lx\n",
                 prange->svms, prange->start, prange->last, start, last, size);

        if (start > prange->start) {
                r = svm_range_split(prange, start, prange->last, &head);
                if (r)
                        return r;
                svm_range_add_child(parent, mm, head, SVM_OP_ADD_RANGE);
        }

        if (last < prange->last) {
                r = svm_range_split(prange, prange->start, last, &tail);
                if (r)
                        return r;
                svm_range_add_child(parent, mm, tail, SVM_OP_ADD_RANGE);
        }

        /* xnack on, update mapping on GPUs with ACCESS_IN_PLACE */
        if (p->xnack_enabled && prange->work_item.op == SVM_OP_ADD_RANGE) {
                prange->work_item.op = SVM_OP_ADD_RANGE_AND_MAP;
                pr_debug("change prange 0x%p [0x%lx 0x%lx] op %d\n",
                         prange, prange->start, prange->last,
                         SVM_OP_ADD_RANGE_AND_MAP);
        }
        return 0;
}

static uint64_t
svm_range_get_pte_flags(struct amdgpu_device *adev, struct svm_range *prange,
                        int domain)
{
        struct amdgpu_device *bo_adev;
        uint32_t flags = prange->flags;
        uint32_t mapping_flags = 0;
        uint64_t pte_flags;
        bool snoop = (domain != SVM_RANGE_VRAM_DOMAIN);
        bool coherent = flags & KFD_IOCTL_SVM_FLAG_COHERENT;

        if (domain == SVM_RANGE_VRAM_DOMAIN)
                bo_adev = amdgpu_ttm_adev(prange->svm_bo->bo->tbo.bdev);

        switch (KFD_GC_VERSION(adev->kfd.dev)) {
        case IP_VERSION(9, 4, 1):
                if (domain == SVM_RANGE_VRAM_DOMAIN) {
                        if (bo_adev == adev) {
                                mapping_flags |= coherent ?
                                        AMDGPU_VM_MTYPE_CC : AMDGPU_VM_MTYPE_RW;
                        } else {
                                mapping_flags |= coherent ?
                                        AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
                                if (amdgpu_xgmi_same_hive(adev, bo_adev))
                                        snoop = true;
                        }
                } else {
                        mapping_flags |= coherent ?
                                AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
                }
                break;
        case IP_VERSION(9, 4, 2):
                if (domain == SVM_RANGE_VRAM_DOMAIN) {
                        if (bo_adev == adev) {
                                mapping_flags |= coherent ?
                                        AMDGPU_VM_MTYPE_CC : AMDGPU_VM_MTYPE_RW;
                                if (adev->gmc.xgmi.connected_to_cpu)
                                        snoop = true;
                        } else {
                                mapping_flags |= coherent ?
                                        AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
                                if (amdgpu_xgmi_same_hive(adev, bo_adev))
                                        snoop = true;
                        }
                } else {
                        mapping_flags |= coherent ?
                                AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
                }
                break;
        default:
                mapping_flags |= coherent ?
                        AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
        }

        mapping_flags |= AMDGPU_VM_PAGE_READABLE | AMDGPU_VM_PAGE_WRITEABLE;

        if (flags & KFD_IOCTL_SVM_FLAG_GPU_RO)
                mapping_flags &= ~AMDGPU_VM_PAGE_WRITEABLE;
        if (flags & KFD_IOCTL_SVM_FLAG_GPU_EXEC)
                mapping_flags |= AMDGPU_VM_PAGE_EXECUTABLE;

        pte_flags = AMDGPU_PTE_VALID;
        pte_flags |= (domain == SVM_RANGE_VRAM_DOMAIN) ? 0 : AMDGPU_PTE_SYSTEM;
        pte_flags |= snoop ? AMDGPU_PTE_SNOOPED : 0;

        pte_flags |= amdgpu_gem_va_map_flags(adev, mapping_flags);
        return pte_flags;
}

static int
svm_range_unmap_from_gpu(struct amdgpu_device *adev, struct amdgpu_vm *vm,
                         uint64_t start, uint64_t last,
                         struct dma_fence **fence)
{
        uint64_t init_pte_value = 0;

        pr_debug("[0x%llx 0x%llx]\n", start, last);

        return amdgpu_vm_update_range(adev, vm, false, true, true, NULL, start,
                                      last, init_pte_value, 0, 0, NULL, NULL,
                                      fence);
}

static int
svm_range_unmap_from_gpus(struct svm_range *prange, unsigned long start,
                          unsigned long last, uint32_t trigger)
{
        DECLARE_BITMAP(bitmap, MAX_GPU_INSTANCE);
        struct kfd_process_device *pdd;
        struct dma_fence *fence = NULL;
        struct kfd_process *p;
        uint32_t gpuidx;
        int r = 0;

        if (!prange->mapped_to_gpu) {
                pr_debug("prange 0x%p [0x%lx 0x%lx] not mapped to GPU\n",
                         prange, prange->start, prange->last);
                return 0;
        }

        if (prange->start == start && prange->last == last) {
                pr_debug("unmap svms 0x%p prange 0x%p\n", prange->svms, prange);
                prange->mapped_to_gpu = false;
        }

        bitmap_or(bitmap, prange->bitmap_access, prange->bitmap_aip,
                  MAX_GPU_INSTANCE);
        p = container_of(prange->svms, struct kfd_process, svms);

        for_each_set_bit(gpuidx, bitmap, MAX_GPU_INSTANCE) {
                pr_debug("unmap from gpu idx 0x%x\n", gpuidx);
                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        return -EINVAL;
                }

                kfd_smi_event_unmap_from_gpu(pdd->dev, p->lead_thread->pid,
                                             start, last, trigger);

                r = svm_range_unmap_from_gpu(pdd->dev->adev,
                                             drm_priv_to_vm(pdd->drm_priv),
                                             start, last, &fence);
                if (r)
                        break;

                if (fence) {
                        r = dma_fence_wait(fence, false);
                        dma_fence_put(fence);
                        fence = NULL;
                        if (r)
                                break;
                }
                kfd_flush_tlb(pdd, TLB_FLUSH_HEAVYWEIGHT);
        }

        return r;
}

static int
svm_range_map_to_gpu(struct kfd_process_device *pdd, struct svm_range *prange,
                     unsigned long offset, unsigned long npages, bool readonly,
                     dma_addr_t *dma_addr, struct amdgpu_device *bo_adev,
                     struct dma_fence **fence, bool flush_tlb)
{
        struct amdgpu_device *adev = pdd->dev->adev;
        struct amdgpu_vm *vm = drm_priv_to_vm(pdd->drm_priv);
        uint64_t pte_flags;
        unsigned long last_start;
        int last_domain;
        int r = 0;
        int64_t i, j;

        last_start = prange->start + offset;

        pr_debug("svms 0x%p [0x%lx 0x%lx] readonly %d\n", prange->svms,
                 last_start, last_start + npages - 1, readonly);

        for (i = offset; i < offset + npages; i++) {
                last_domain = dma_addr[i] & SVM_RANGE_VRAM_DOMAIN;
                dma_addr[i] &= ~SVM_RANGE_VRAM_DOMAIN;

                /* Collect all pages in the same address range and memory domain
                 * that can be mapped with a single call to update mapping.
                 */
                if (i < offset + npages - 1 &&
                    last_domain == (dma_addr[i + 1] & SVM_RANGE_VRAM_DOMAIN))
                        continue;

                pr_debug("Mapping range [0x%lx 0x%llx] on domain: %s\n",
                         last_start, prange->start + i, last_domain ? "GPU" : "CPU");

                pte_flags = svm_range_get_pte_flags(adev, prange, last_domain);
                if (readonly)
                        pte_flags &= ~AMDGPU_PTE_WRITEABLE;

                pr_debug("svms 0x%p map [0x%lx 0x%llx] vram %d PTE 0x%llx\n",
                         prange->svms, last_start, prange->start + i,
                         (last_domain == SVM_RANGE_VRAM_DOMAIN) ? 1 : 0,
                         pte_flags);

                r = amdgpu_vm_update_range(adev, vm, false, false, flush_tlb, NULL,
                                           last_start, prange->start + i,
                                           pte_flags,
                                           (last_start - prange->start) << PAGE_SHIFT,
                                           bo_adev ? bo_adev->vm_manager.vram_base_offset : 0,
                                           NULL, dma_addr, &vm->last_update);

                for (j = last_start - prange->start; j <= i; j++)
                        dma_addr[j] |= last_domain;

                if (r) {
                        pr_debug("failed %d to map to gpu 0x%lx\n", r, prange->start);
                        goto out;
                }
                last_start = prange->start + i + 1;
        }

        r = amdgpu_vm_update_pdes(adev, vm, false);
        if (r) {
                pr_debug("failed %d to update directories 0x%lx\n", r,
                         prange->start);
                goto out;
        }

        if (fence)
                *fence = dma_fence_get(vm->last_update);

out:
        return r;
}

static int
svm_range_map_to_gpus(struct svm_range *prange, unsigned long offset,
                      unsigned long npages, bool readonly,
                      unsigned long *bitmap, bool wait, bool flush_tlb)
{
        struct kfd_process_device *pdd;
        struct amdgpu_device *bo_adev;
        struct kfd_process *p;
        struct dma_fence *fence = NULL;
        uint32_t gpuidx;
        int r = 0;

        if (prange->svm_bo && prange->ttm_res)
                bo_adev = amdgpu_ttm_adev(prange->svm_bo->bo->tbo.bdev);
        else
                bo_adev = NULL;

        p = container_of(prange->svms, struct kfd_process, svms);
        for_each_set_bit(gpuidx, bitmap, MAX_GPU_INSTANCE) {
                pr_debug("mapping to gpu idx 0x%x\n", gpuidx);
                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        return -EINVAL;
                }

                pdd = kfd_bind_process_to_device(pdd->dev, p);
                if (IS_ERR(pdd))
                        return -EINVAL;

                if (bo_adev && pdd->dev->adev != bo_adev &&
                    !amdgpu_xgmi_same_hive(pdd->dev->adev, bo_adev)) {
                        pr_debug("cannot map to device idx %d\n", gpuidx);
                        continue;
                }

                r = svm_range_map_to_gpu(pdd, prange, offset, npages, readonly,
                                         prange->dma_addr[gpuidx],
                                         bo_adev, wait ? &fence : NULL,
                                         flush_tlb);
                if (r)
                        break;

                if (fence) {
                        r = dma_fence_wait(fence, false);
                        dma_fence_put(fence);
                        fence = NULL;
                        if (r) {
                                pr_debug("failed %d to dma fence wait\n", r);
                                break;
                        }
                }

                kfd_flush_tlb(pdd, TLB_FLUSH_LEGACY);
        }

        return r;
}

struct svm_validate_context {
        struct kfd_process *process;
        struct svm_range *prange;
        bool intr;
        DECLARE_BITMAP(bitmap, MAX_GPU_INSTANCE);
        struct ttm_validate_buffer tv[MAX_GPU_INSTANCE];
        struct list_head validate_list;
        struct ww_acquire_ctx ticket;
};

static int svm_range_reserve_bos(struct svm_validate_context *ctx)
{
        struct kfd_process_device *pdd;
        struct amdgpu_vm *vm;
        uint32_t gpuidx;
        int r;

        INIT_LIST_HEAD(&ctx->validate_list);
        for_each_set_bit(gpuidx, ctx->bitmap, MAX_GPU_INSTANCE) {
                pdd = kfd_process_device_from_gpuidx(ctx->process, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        return -EINVAL;
                }
                vm = drm_priv_to_vm(pdd->drm_priv);

                ctx->tv[gpuidx].bo = &vm->root.bo->tbo;
                ctx->tv[gpuidx].num_shared = 4;
                list_add(&ctx->tv[gpuidx].head, &ctx->validate_list);
        }

        r = ttm_eu_reserve_buffers(&ctx->ticket, &ctx->validate_list,
                                   ctx->intr, NULL);
        if (r) {
                pr_debug("failed %d to reserve bo\n", r);
                return r;
        }

        for_each_set_bit(gpuidx, ctx->bitmap, MAX_GPU_INSTANCE) {
                pdd = kfd_process_device_from_gpuidx(ctx->process, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        r = -EINVAL;
                        goto unreserve_out;
                }

                r = amdgpu_vm_validate_pt_bos(pdd->dev->adev,
                                              drm_priv_to_vm(pdd->drm_priv),
                                              svm_range_bo_validate, NULL);
                if (r) {
                        pr_debug("failed %d validate pt bos\n", r);
                        goto unreserve_out;
                }
        }

        return 0;

unreserve_out:
        ttm_eu_backoff_reservation(&ctx->ticket, &ctx->validate_list);
        return r;
}

static void svm_range_unreserve_bos(struct svm_validate_context *ctx)
{
        ttm_eu_backoff_reservation(&ctx->ticket, &ctx->validate_list);
}

static void *kfd_svm_page_owner(struct kfd_process *p, int32_t gpuidx)
{
        struct kfd_process_device *pdd;

        pdd = kfd_process_device_from_gpuidx(p, gpuidx);

        return SVM_ADEV_PGMAP_OWNER(pdd->dev->adev);
}

/*
 * Validation+GPU mapping with concurrent invalidation (MMU notifiers)
 *
 * To prevent concurrent destruction or change of range attributes, the
 * svm_read_lock must be held. The caller must not hold the svm_write_lock
 * because that would block concurrent evictions and lead to deadlocks. To
 * serialize concurrent migrations or validations of the same range, the
 * prange->migrate_mutex must be held.
 *
 * For VRAM ranges, the SVM BO must be allocated and valid (protected by its
 * eviction fence.
 *
 * The following sequence ensures race-free validation and GPU mapping:
 *
 * 1. Reserve page table (and SVM BO if range is in VRAM)
 * 2. hmm_range_fault to get page addresses (if system memory)
 * 3. DMA-map pages (if system memory)
 * 4-a. Take notifier lock
 * 4-b. Check that pages still valid (mmu_interval_read_retry)
 * 4-c. Check that the range was not split or otherwise invalidated
 * 4-d. Update GPU page table
 * 4.e. Release notifier lock
 * 5. Release page table (and SVM BO) reservation
 */
static int svm_range_validate_and_map(struct mm_struct *mm,
                                      struct svm_range *prange, int32_t gpuidx,
                                      bool intr, bool wait, bool flush_tlb)
{
        struct svm_validate_context ctx;
        unsigned long start, end, addr;
        struct kfd_process *p;
        void *owner;
        int32_t idx;
        int r = 0;

        ctx.process = container_of(prange->svms, struct kfd_process, svms);
        ctx.prange = prange;
        ctx.intr = intr;

        if (gpuidx < MAX_GPU_INSTANCE) {
                bitmap_zero(ctx.bitmap, MAX_GPU_INSTANCE);
                bitmap_set(ctx.bitmap, gpuidx, 1);
        } else if (ctx.process->xnack_enabled) {
                bitmap_copy(ctx.bitmap, prange->bitmap_aip, MAX_GPU_INSTANCE);

                /* If prefetch range to GPU, or GPU retry fault migrate range to
                 * GPU, which has ACCESS attribute to the range, create mapping
                 * on that GPU.
                 */
                if (prange->actual_loc) {
                        gpuidx = kfd_process_gpuidx_from_gpuid(ctx.process,
                                                        prange->actual_loc);
                        if (gpuidx < 0) {
                                WARN_ONCE(1, "failed get device by id 0x%x\n",
                                         prange->actual_loc);
                                return -EINVAL;
                        }
                        if (test_bit(gpuidx, prange->bitmap_access))
                                bitmap_set(ctx.bitmap, gpuidx, 1);
                }
        } else {
                bitmap_or(ctx.bitmap, prange->bitmap_access,
                          prange->bitmap_aip, MAX_GPU_INSTANCE);
        }

        if (bitmap_empty(ctx.bitmap, MAX_GPU_INSTANCE)) {
                if (!prange->mapped_to_gpu)
                        return 0;

                bitmap_copy(ctx.bitmap, prange->bitmap_access, MAX_GPU_INSTANCE);
        }

        if (prange->actual_loc && !prange->ttm_res) {
                /* This should never happen. actual_loc gets set by
                 * svm_migrate_ram_to_vram after allocating a BO.
                 */
                WARN_ONCE(1, "VRAM BO missing during validation\n");
                return -EINVAL;
        }

        svm_range_reserve_bos(&ctx);

        p = container_of(prange->svms, struct kfd_process, svms);
        owner = kfd_svm_page_owner(p, find_first_bit(ctx.bitmap,
                                                MAX_GPU_INSTANCE));
        for_each_set_bit(idx, ctx.bitmap, MAX_GPU_INSTANCE) {
                if (kfd_svm_page_owner(p, idx) != owner) {
                        owner = NULL;
                        break;
                }
        }

        start = prange->start << PAGE_SHIFT;
        end = (prange->last + 1) << PAGE_SHIFT;
        for (addr = start; addr < end && !r; ) {
                struct hmm_range *hmm_range;
                struct vm_area_struct *vma;
                unsigned long next;
                unsigned long offset;
                unsigned long npages;
                bool readonly;

                vma = find_vma(mm, addr);
                if (!vma || addr < vma->vm_start) {
                        r = -EFAULT;
                        goto unreserve_out;
                }
                readonly = !(vma->vm_flags & VM_WRITE);

                next = min(vma->vm_end, end);
                npages = (next - addr) >> PAGE_SHIFT;
                WRITE_ONCE(p->svms.faulting_task, current);
                r = amdgpu_hmm_range_get_pages(&prange->notifier, mm, NULL,
                                               addr, npages, &hmm_range,
                                               readonly, true, owner);
                WRITE_ONCE(p->svms.faulting_task, NULL);
                if (r) {
                        pr_debug("failed %d to get svm range pages\n", r);
                        goto unreserve_out;
                }

                offset = (addr - start) >> PAGE_SHIFT;
                r = svm_range_dma_map(prange, ctx.bitmap, offset, npages,
                                      hmm_range->hmm_pfns);
                if (r) {
                        pr_debug("failed %d to dma map range\n", r);
                        goto unreserve_out;
                }

                svm_range_lock(prange);
                if (amdgpu_hmm_range_get_pages_done(hmm_range)) {
                        pr_debug("hmm update the range, need validate again\n");
                        r = -EAGAIN;
                        goto unlock_out;
                }
                if (!list_empty(&prange->child_list)) {
                        pr_debug("range split by unmap in parallel, validate again\n");
                        r = -EAGAIN;
                        goto unlock_out;
                }

                r = svm_range_map_to_gpus(prange, offset, npages, readonly,
                                          ctx.bitmap, wait, flush_tlb);

unlock_out:
                svm_range_unlock(prange);

                addr = next;
        }

        if (addr == end) {
                prange->validated_once = true;
                prange->mapped_to_gpu = true;
        }

unreserve_out:
        svm_range_unreserve_bos(&ctx);

        if (!r)
                prange->validate_timestamp = ktime_get_boottime();

        return r;
}

/**
 * svm_range_list_lock_and_flush_work - flush pending deferred work
 *
 * @svms: the svm range list
 * @mm: the mm structure
 *
 * Context: Returns with mmap write lock held, pending deferred work flushed
 *
 */
void
svm_range_list_lock_and_flush_work(struct svm_range_list *svms,
                                   struct mm_struct *mm)
{
retry_flush_work:
        flush_work(&svms->deferred_list_work);
        mmap_write_lock(mm);

        if (list_empty(&svms->deferred_range_list))
                return;
        mmap_write_unlock(mm);
        pr_debug("retry flush\n");
        goto retry_flush_work;
}

static void svm_range_restore_work(struct work_struct *work)
{
        struct delayed_work *dwork = to_delayed_work(work);
        struct amdkfd_process_info *process_info;
        struct svm_range_list *svms;
        struct svm_range *prange;
        struct kfd_process *p;
        struct mm_struct *mm;
        int evicted_ranges;
        int invalid;
        int r;

        svms = container_of(dwork, struct svm_range_list, restore_work);
        evicted_ranges = atomic_read(&svms->evicted_ranges);
        if (!evicted_ranges)
                return;

        pr_debug("restore svm ranges\n");

        p = container_of(svms, struct kfd_process, svms);
        process_info = p->kgd_process_info;

        /* Keep mm reference when svm_range_validate_and_map ranges */
        mm = get_task_mm(p->lead_thread);
        if (!mm) {
                pr_debug("svms 0x%p process mm gone\n", svms);
                return;
        }

        mutex_lock(&process_info->lock);
        svm_range_list_lock_and_flush_work(svms, mm);
        mutex_lock(&svms->lock);

        evicted_ranges = atomic_read(&svms->evicted_ranges);

        list_for_each_entry(prange, &svms->list, list) {
                invalid = atomic_read(&prange->invalid);
                if (!invalid)
                        continue;

                pr_debug("restoring svms 0x%p prange 0x%p [0x%lx %lx] inv %d\n",
                         prange->svms, prange, prange->start, prange->last,
                         invalid);

                /*
                 * If range is migrating, wait for migration is done.
                 */
                mutex_lock(&prange->migrate_mutex);

                r = svm_range_validate_and_map(mm, prange, MAX_GPU_INSTANCE,
                                               false, true, false);
                if (r)
                        pr_debug("failed %d to map 0x%lx to gpus\n", r,
                                 prange->start);

                mutex_unlock(&prange->migrate_mutex);
                if (r)
                        goto out_reschedule;

                if (atomic_cmpxchg(&prange->invalid, invalid, 0) != invalid)
                        goto out_reschedule;
        }

        if (atomic_cmpxchg(&svms->evicted_ranges, evicted_ranges, 0) !=
            evicted_ranges)
                goto out_reschedule;

        evicted_ranges = 0;

        r = kgd2kfd_resume_mm(mm);
        if (r) {
                /* No recovery from this failure. Probably the CP is
                 * hanging. No point trying again.
                 */
                pr_debug("failed %d to resume KFD\n", r);
        }

        pr_debug("restore svm ranges successfully\n");

out_reschedule:
        mutex_unlock(&svms->lock);
        mmap_write_unlock(mm);
        mutex_unlock(&process_info->lock);

        /* If validation failed, reschedule another attempt */
        if (evicted_ranges) {
                pr_debug("reschedule to restore svm range\n");
                schedule_delayed_work(&svms->restore_work,
                        msecs_to_jiffies(AMDGPU_SVM_RANGE_RESTORE_DELAY_MS));

                kfd_smi_event_queue_restore_rescheduled(mm);
        }
        mmput(mm);
}

/**
 * svm_range_evict - evict svm range
 * @prange: svm range structure
 * @mm: current process mm_struct
 * @start: starting process queue number
 * @last: last process queue number
 *
 * Stop all queues of the process to ensure GPU doesn't access the memory, then
 * return to let CPU evict the buffer and proceed CPU pagetable update.
 *
 * Don't need use lock to sync cpu pagetable invalidation with GPU execution.
 * If invalidation happens while restore work is running, restore work will
 * restart to ensure to get the latest CPU pages mapping to GPU, then start
 * the queues.
 */
static int
svm_range_evict(struct svm_range *prange, struct mm_struct *mm,
                unsigned long start, unsigned long last,
                enum mmu_notifier_event event)
{
        struct svm_range_list *svms = prange->svms;
        struct svm_range *pchild;
        struct kfd_process *p;
        int r = 0;

        p = container_of(svms, struct kfd_process, svms);

        pr_debug("invalidate svms 0x%p prange [0x%lx 0x%lx] [0x%lx 0x%lx]\n",
                 svms, prange->start, prange->last, start, last);

        if (!p->xnack_enabled ||
            (prange->flags & KFD_IOCTL_SVM_FLAG_GPU_ALWAYS_MAPPED)) {
                int evicted_ranges;
                bool mapped = prange->mapped_to_gpu;

                list_for_each_entry(pchild, &prange->child_list, child_list) {
                        if (!pchild->mapped_to_gpu)
                                continue;
                        mapped = true;
                        mutex_lock_nested(&pchild->lock, 1);
                        if (pchild->start <= last && pchild->last >= start) {
                                pr_debug("increment pchild invalid [0x%lx 0x%lx]\n",
                                         pchild->start, pchild->last);
                                atomic_inc(&pchild->invalid);
                        }
                        mutex_unlock(&pchild->lock);
                }

                if (!mapped)
                        return r;

                if (prange->start <= last && prange->last >= start)
                        atomic_inc(&prange->invalid);

                evicted_ranges = atomic_inc_return(&svms->evicted_ranges);
                if (evicted_ranges != 1)
                        return r;

                pr_debug("evicting svms 0x%p range [0x%lx 0x%lx]\n",
                         prange->svms, prange->start, prange->last);

                /* First eviction, stop the queues */
                r = kgd2kfd_quiesce_mm(mm, KFD_QUEUE_EVICTION_TRIGGER_SVM);
                if (r)
                        pr_debug("failed to quiesce KFD\n");

                pr_debug("schedule to restore svm %p ranges\n", svms);
                schedule_delayed_work(&svms->restore_work,
                        msecs_to_jiffies(AMDGPU_SVM_RANGE_RESTORE_DELAY_MS));
        } else {
                unsigned long s, l;
                uint32_t trigger;

                if (event == MMU_NOTIFY_MIGRATE)
                        trigger = KFD_SVM_UNMAP_TRIGGER_MMU_NOTIFY_MIGRATE;
                else
                        trigger = KFD_SVM_UNMAP_TRIGGER_MMU_NOTIFY;

                pr_debug("invalidate unmap svms 0x%p [0x%lx 0x%lx] from GPUs\n",
                         prange->svms, start, last);
                list_for_each_entry(pchild, &prange->child_list, child_list) {
                        mutex_lock_nested(&pchild->lock, 1);
                        s = max(start, pchild->start);
                        l = min(last, pchild->last);
                        if (l >= s)
                                svm_range_unmap_from_gpus(pchild, s, l, trigger);
                        mutex_unlock(&pchild->lock);
                }
                s = max(start, prange->start);
                l = min(last, prange->last);
                if (l >= s)
                        svm_range_unmap_from_gpus(prange, s, l, trigger);
        }

        return r;
}

static struct svm_range *svm_range_clone(struct svm_range *old)
{
        struct svm_range *new;

        new = svm_range_new(old->svms, old->start, old->last, false);
        if (!new)
                return NULL;

        if (old->svm_bo) {
                new->ttm_res = old->ttm_res;
                new->offset = old->offset;
                new->svm_bo = svm_range_bo_ref(old->svm_bo);
                spin_lock(&new->svm_bo->list_lock);
                list_add(&new->svm_bo_list, &new->svm_bo->range_list);
                spin_unlock(&new->svm_bo->list_lock);
        }
        new->flags = old->flags;
        new->preferred_loc = old->preferred_loc;
        new->prefetch_loc = old->prefetch_loc;
        new->actual_loc = old->actual_loc;
        new->granularity = old->granularity;
        new->mapped_to_gpu = old->mapped_to_gpu;
        bitmap_copy(new->bitmap_access, old->bitmap_access, MAX_GPU_INSTANCE);
        bitmap_copy(new->bitmap_aip, old->bitmap_aip, MAX_GPU_INSTANCE);

        return new;
}

void svm_range_set_max_pages(struct amdgpu_device *adev)
{
        uint64_t max_pages;
        uint64_t pages, _pages;

        /* 1/32 VRAM size in pages */
        pages = adev->gmc.real_vram_size >> 17;
        pages = clamp(pages, 1ULL << 9, 1ULL << 18);
        pages = rounddown_pow_of_two(pages);
        do {
                max_pages = READ_ONCE(max_svm_range_pages);
                _pages = min_not_zero(max_pages, pages);
        } while (cmpxchg(&max_svm_range_pages, max_pages, _pages) != max_pages);
}

static int
svm_range_split_new(struct svm_range_list *svms, uint64_t start, uint64_t last,
                    uint64_t max_pages, struct list_head *insert_list,
                    struct list_head *update_list)
{
        struct svm_range *prange;
        uint64_t l;

        pr_debug("max_svm_range_pages 0x%llx adding [0x%llx 0x%llx]\n",
                 max_pages, start, last);

        while (last >= start) {
                l = min(last, ALIGN_DOWN(start + max_pages, max_pages) - 1);

                prange = svm_range_new(svms, start, l, true);
                if (!prange)
                        return -ENOMEM;
                list_add(&prange->list, insert_list);
                list_add(&prange->update_list, update_list);

                start = l + 1;
        }
        return 0;
}

/**
 * svm_range_add - add svm range and handle overlap
 * @p: the range add to this process svms
 * @start: page size aligned
 * @size: page size aligned
 * @nattr: number of attributes
 * @attrs: array of attributes
 * @update_list: output, the ranges need validate and update GPU mapping
 * @insert_list: output, the ranges need insert to svms
 * @remove_list: output, the ranges are replaced and need remove from svms
 *
 * Check if the virtual address range has overlap with any existing ranges,
 * split partly overlapping ranges and add new ranges in the gaps. All changes
 * should be applied to the range_list and interval tree transactionally. If
 * any range split or allocation fails, the entire update fails. Therefore any
 * existing overlapping svm_ranges are cloned and the original svm_ranges left
 * unchanged.
 *
 * If the transaction succeeds, the caller can update and insert clones and
 * new ranges, then free the originals.
 *
 * Otherwise the caller can free the clones and new ranges, while the old
 * svm_ranges remain unchanged.
 *
 * Context: Process context, caller must hold svms->lock
 *
 * Return:
 * 0 - OK, otherwise error code
 */
static int
svm_range_add(struct kfd_process *p, uint64_t start, uint64_t size,
              uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs,
              struct list_head *update_list, struct list_head *insert_list,
              struct list_head *remove_list)
{
        unsigned long last = start + size - 1UL;
        struct svm_range_list *svms = &p->svms;
        struct interval_tree_node *node;
        struct svm_range *prange;
        struct svm_range *tmp;
        struct list_head new_list;
        int r = 0;

        pr_debug("svms 0x%p [0x%llx 0x%lx]\n", &p->svms, start, last);

        INIT_LIST_HEAD(update_list);
        INIT_LIST_HEAD(insert_list);
        INIT_LIST_HEAD(remove_list);
        INIT_LIST_HEAD(&new_list);

        node = interval_tree_iter_first(&svms->objects, start, last);
        while (node) {
                struct interval_tree_node *next;
                unsigned long next_start;

                pr_debug("found overlap node [0x%lx 0x%lx]\n", node->start,
                         node->last);

                prange = container_of(node, struct svm_range, it_node);
                next = interval_tree_iter_next(node, start, last);
                next_start = min(node->last, last) + 1;

                if (svm_range_is_same_attrs(p, prange, nattr, attrs)) {
                        /* nothing to do */
                } else if (node->start < start || node->last > last) {
                        /* node intersects the update range and its attributes
                         * will change. Clone and split it, apply updates only
                         * to the overlapping part
                         */
                        struct svm_range *old = prange;

                        prange = svm_range_clone(old);
                        if (!prange) {
                                r = -ENOMEM;
                                goto out;
                        }

                        list_add(&old->update_list, remove_list);
                        list_add(&prange->list, insert_list);
                        list_add(&prange->update_list, update_list);

                        if (node->start < start) {
                                pr_debug("change old range start\n");
                                r = svm_range_split_head(prange, start,
                                                         insert_list);
                                if (r)
                                        goto out;
                        }
                        if (node->last > last) {
                                pr_debug("change old range last\n");
                                r = svm_range_split_tail(prange, last,
                                                         insert_list);
                                if (r)
                                        goto out;
                        }
                } else {
                        /* The node is contained within start..last,
                         * just update it
                         */
                        list_add(&prange->update_list, update_list);
                }

                /* insert a new node if needed */
                if (node->start > start) {
                        r = svm_range_split_new(svms, start, node->start - 1,
                                                READ_ONCE(max_svm_range_pages),
                                                &new_list, update_list);
                        if (r)
                                goto out;
                }

                node = next;
                start = next_start;
        }

        /* add a final range at the end if needed */
        if (start <= last)
                r = svm_range_split_new(svms, start, last,
                                        READ_ONCE(max_svm_range_pages),
                                        &new_list, update_list);

out:
        if (r) {
                list_for_each_entry_safe(prange, tmp, insert_list, list)
                        svm_range_free(prange, false);
                list_for_each_entry_safe(prange, tmp, &new_list, list)
                        svm_range_free(prange, true);
        } else {
                list_splice(&new_list, insert_list);
        }

        return r;
}

static void
svm_range_update_notifier_and_interval_tree(struct mm_struct *mm,
                                            struct svm_range *prange)
{
        unsigned long start;
        unsigned long last;

        start = prange->notifier.interval_tree.start >> PAGE_SHIFT;
        last = prange->notifier.interval_tree.last >> PAGE_SHIFT;

        if (prange->start == start && prange->last == last)
                return;

        pr_debug("up notifier 0x%p prange 0x%p [0x%lx 0x%lx] [0x%lx 0x%lx]\n",
                  prange->svms, prange, start, last, prange->start,
                  prange->last);

        if (start != 0 && last != 0) {
                interval_tree_remove(&prange->it_node, &prange->svms->objects);
                svm_range_remove_notifier(prange);
        }
        prange->it_node.start = prange->start;
        prange->it_node.last = prange->last;

        interval_tree_insert(&prange->it_node, &prange->svms->objects);
        svm_range_add_notifier_locked(mm, prange);
}

static void
svm_range_handle_list_op(struct svm_range_list *svms, struct svm_range *prange,
                         struct mm_struct *mm)
{
        switch (prange->work_item.op) {
        case SVM_OP_NULL:
                pr_debug("NULL OP 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                         svms, prange, prange->start, prange->last);
                break;
        case SVM_OP_UNMAP_RANGE:
                pr_debug("remove 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                         svms, prange, prange->start, prange->last);
                svm_range_unlink(prange);
                svm_range_remove_notifier(prange);
                svm_range_free(prange, true);
                break;
        case SVM_OP_UPDATE_RANGE_NOTIFIER:
                pr_debug("update notifier 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                         svms, prange, prange->start, prange->last);
                svm_range_update_notifier_and_interval_tree(mm, prange);
                break;
        case SVM_OP_UPDATE_RANGE_NOTIFIER_AND_MAP:
                pr_debug("update and map 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                         svms, prange, prange->start, prange->last);
                svm_range_update_notifier_and_interval_tree(mm, prange);
                /* TODO: implement deferred validation and mapping */
                break;
        case SVM_OP_ADD_RANGE:
                pr_debug("add 0x%p prange 0x%p [0x%lx 0x%lx]\n", svms, prange,
                         prange->start, prange->last);
                svm_range_add_to_svms(prange);
                svm_range_add_notifier_locked(mm, prange);
                break;
        case SVM_OP_ADD_RANGE_AND_MAP:
                pr_debug("add and map 0x%p prange 0x%p [0x%lx 0x%lx]\n", svms,
                         prange, prange->start, prange->last);
                svm_range_add_to_svms(prange);
                svm_range_add_notifier_locked(mm, prange);
                /* TODO: implement deferred validation and mapping */
                break;
        default:
                WARN_ONCE(1, "Unknown prange 0x%p work op %d\n", prange,
                         prange->work_item.op);
        }
}

static void svm_range_drain_retry_fault(struct svm_range_list *svms)
{
        struct kfd_process_device *pdd;
        struct kfd_process *p;
        int drain;
        uint32_t i;

        p = container_of(svms, struct kfd_process, svms);

restart:
        drain = atomic_read(&svms->drain_pagefaults);
        if (!drain)
                return;

        for_each_set_bit(i, svms->bitmap_supported, p->n_pdds) {
                pdd = p->pdds[i];
                if (!pdd)
                        continue;

                pr_debug("drain retry fault gpu %d svms %p\n", i, svms);

                amdgpu_ih_wait_on_checkpoint_process_ts(pdd->dev->adev,
                                                     &pdd->dev->adev->irq.ih1);
                pr_debug("drain retry fault gpu %d svms 0x%p done\n", i, svms);
        }
        if (atomic_cmpxchg(&svms->drain_pagefaults, drain, 0) != drain)
                goto restart;
}

static void svm_range_deferred_list_work(struct work_struct *work)
{
        struct svm_range_list *svms;
        struct svm_range *prange;
        struct mm_struct *mm;

        svms = container_of(work, struct svm_range_list, deferred_list_work);
        pr_debug("enter svms 0x%p\n", svms);

        spin_lock(&svms->deferred_list_lock);
        while (!list_empty(&svms->deferred_range_list)) {
                prange = list_first_entry(&svms->deferred_range_list,
                                          struct svm_range, deferred_list);
                spin_unlock(&svms->deferred_list_lock);

                pr_debug("prange 0x%p [0x%lx 0x%lx] op %d\n", prange,
                         prange->start, prange->last, prange->work_item.op);

                mm = prange->work_item.mm;
retry:
                mmap_write_lock(mm);

                /* Checking for the need to drain retry faults must be inside
                 * mmap write lock to serialize with munmap notifiers.
                 */
                if (unlikely(atomic_read(&svms->drain_pagefaults))) {
                        mmap_write_unlock(mm);
                        svm_range_drain_retry_fault(svms);
                        goto retry;
                }

                /* Remove from deferred_list must be inside mmap write lock, for
                 * two race cases:
                 * 1. unmap_from_cpu may change work_item.op and add the range
                 *    to deferred_list again, cause use after free bug.
                 * 2. svm_range_list_lock_and_flush_work may hold mmap write
                 *    lock and continue because deferred_list is empty, but
                 *    deferred_list work is actually waiting for mmap lock.
                 */
                spin_lock(&svms->deferred_list_lock);
                list_del_init(&prange->deferred_list);
                spin_unlock(&svms->deferred_list_lock);

                mutex_lock(&svms->lock);
                mutex_lock(&prange->migrate_mutex);
                while (!list_empty(&prange->child_list)) {
                        struct svm_range *pchild;

                        pchild = list_first_entry(&prange->child_list,
                                                struct svm_range, child_list);
                        pr_debug("child prange 0x%p op %d\n", pchild,
                                 pchild->work_item.op);
                        list_del_init(&pchild->child_list);
                        svm_range_handle_list_op(svms, pchild, mm);
                }
                mutex_unlock(&prange->migrate_mutex);

                svm_range_handle_list_op(svms, prange, mm);
                mutex_unlock(&svms->lock);
                mmap_write_unlock(mm);

                /* Pairs with mmget in svm_range_add_list_work */
                mmput(mm);

                spin_lock(&svms->deferred_list_lock);
        }
        spin_unlock(&svms->deferred_list_lock);
        pr_debug("exit svms 0x%p\n", svms);
}

void
svm_range_add_list_work(struct svm_range_list *svms, struct svm_range *prange,
                        struct mm_struct *mm, enum svm_work_list_ops op)
{
        spin_lock(&svms->deferred_list_lock);
        /* if prange is on the deferred list */
        if (!list_empty(&prange->deferred_list)) {
                pr_debug("update exist prange 0x%p work op %d\n", prange, op);
                WARN_ONCE(prange->work_item.mm != mm, "unmatch mm\n");
                if (op != SVM_OP_NULL &&
                    prange->work_item.op != SVM_OP_UNMAP_RANGE)
                        prange->work_item.op = op;
        } else {
                prange->work_item.op = op;

                /* Pairs with mmput in deferred_list_work */
                mmget(mm);
                prange->work_item.mm = mm;
                list_add_tail(&prange->deferred_list,
                              &prange->svms->deferred_range_list);
                pr_debug("add prange 0x%p [0x%lx 0x%lx] to work list op %d\n",
                         prange, prange->start, prange->last, op);
        }
        spin_unlock(&svms->deferred_list_lock);
}

void schedule_deferred_list_work(struct svm_range_list *svms)
{
        spin_lock(&svms->deferred_list_lock);
        if (!list_empty(&svms->deferred_range_list))
                schedule_work(&svms->deferred_list_work);
        spin_unlock(&svms->deferred_list_lock);
}

static void
svm_range_unmap_split(struct mm_struct *mm, struct svm_range *parent,
                      struct svm_range *prange, unsigned long start,
                      unsigned long last)
{
        struct svm_range *head;
        struct svm_range *tail;

        if (prange->work_item.op == SVM_OP_UNMAP_RANGE) {
                pr_debug("prange 0x%p [0x%lx 0x%lx] is already freed\n", prange,
                         prange->start, prange->last);
                return;
        }
        if (start > prange->last || last < prange->start)
                return;

        head = tail = prange;
        if (start > prange->start)
                svm_range_split(prange, prange->start, start - 1, &tail);
        if (last < tail->last)
                svm_range_split(tail, last + 1, tail->last, &head);

        if (head != prange && tail != prange) {
                svm_range_add_child(parent, mm, head, SVM_OP_UNMAP_RANGE);
                svm_range_add_child(parent, mm, tail, SVM_OP_ADD_RANGE);
        } else if (tail != prange) {
                svm_range_add_child(parent, mm, tail, SVM_OP_UNMAP_RANGE);
        } else if (head != prange) {
                svm_range_add_child(parent, mm, head, SVM_OP_UNMAP_RANGE);
        } else if (parent != prange) {
                prange->work_item.op = SVM_OP_UNMAP_RANGE;
        }
}

static void
svm_range_unmap_from_cpu(struct mm_struct *mm, struct svm_range *prange,
                         unsigned long start, unsigned long last)
{
        uint32_t trigger = KFD_SVM_UNMAP_TRIGGER_UNMAP_FROM_CPU;
        struct svm_range_list *svms;
        struct svm_range *pchild;
        struct kfd_process *p;
        unsigned long s, l;
        bool unmap_parent;

        p = kfd_lookup_process_by_mm(mm);
        if (!p)
                return;
        svms = &p->svms;

        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] [0x%lx 0x%lx]\n", svms,
                 prange, prange->start, prange->last, start, last);

        /* Make sure pending page faults are drained in the deferred worker
         * before the range is freed to avoid straggler interrupts on
         * unmapped memory causing "phantom faults".
         */
        atomic_inc(&svms->drain_pagefaults);

        unmap_parent = start <= prange->start && last >= prange->last;

        list_for_each_entry(pchild, &prange->child_list, child_list) {
                mutex_lock_nested(&pchild->lock, 1);
                s = max(start, pchild->start);
                l = min(last, pchild->last);
                if (l >= s)
                        svm_range_unmap_from_gpus(pchild, s, l, trigger);
                svm_range_unmap_split(mm, prange, pchild, start, last);
                mutex_unlock(&pchild->lock);
        }
        s = max(start, prange->start);
        l = min(last, prange->last);
        if (l >= s)
                svm_range_unmap_from_gpus(prange, s, l, trigger);
        svm_range_unmap_split(mm, prange, prange, start, last);

        if (unmap_parent)
                svm_range_add_list_work(svms, prange, mm, SVM_OP_UNMAP_RANGE);
        else
                svm_range_add_list_work(svms, prange, mm,
                                        SVM_OP_UPDATE_RANGE_NOTIFIER);
        schedule_deferred_list_work(svms);

        kfd_unref_process(p);
}

/**
 * svm_range_cpu_invalidate_pagetables - interval notifier callback
 * @mni: mmu_interval_notifier struct
 * @range: mmu_notifier_range struct
 * @cur_seq: value to pass to mmu_interval_set_seq()
 *
 * If event is MMU_NOTIFY_UNMAP, this is from CPU unmap range, otherwise, it
 * is from migration, or CPU page invalidation callback.
 *
 * For unmap event, unmap range from GPUs, remove prange from svms in a delayed
 * work thread, and split prange if only part of prange is unmapped.
 *
 * For invalidation event, if GPU retry fault is not enabled, evict the queues,
 * then schedule svm_range_restore_work to update GPU mapping and resume queues.
 * If GPU retry fault is enabled, unmap the svm range from GPU, retry fault will
 * update GPU mapping to recover.
 *
 * Context: mmap lock, notifier_invalidate_start lock are held
 *          for invalidate event, prange lock is held if this is from migration
 */
static bool
svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni,
                                    const struct mmu_notifier_range *range,
                                    unsigned long cur_seq)
{
        struct svm_range *prange;
        unsigned long start;
        unsigned long last;

        if (range->event == MMU_NOTIFY_RELEASE)
                return true;
        if (!mmget_not_zero(mni->mm))
                return true;

        start = mni->interval_tree.start;
        last = mni->interval_tree.last;
        start = max(start, range->start) >> PAGE_SHIFT;
        last = min(last, range->end - 1) >> PAGE_SHIFT;
        pr_debug("[0x%lx 0x%lx] range[0x%lx 0x%lx] notifier[0x%lx 0x%lx] %d\n",
                 start, last, range->start >> PAGE_SHIFT,
                 (range->end - 1) >> PAGE_SHIFT,
                 mni->interval_tree.start >> PAGE_SHIFT,
                 mni->interval_tree.last >> PAGE_SHIFT, range->event);

        prange = container_of(mni, struct svm_range, notifier);

        svm_range_lock(prange);
        mmu_interval_set_seq(mni, cur_seq);

        switch (range->event) {
        case MMU_NOTIFY_UNMAP:
                svm_range_unmap_from_cpu(mni->mm, prange, start, last);
                break;
        default:
                svm_range_evict(prange, mni->mm, start, last, range->event);
                break;
        }

        svm_range_unlock(prange);
        mmput(mni->mm);

        return true;
}

/**
 * svm_range_from_addr - find svm range from fault address
 * @svms: svm range list header
 * @addr: address to search range interval tree, in pages
 * @parent: parent range if range is on child list
 *
 * Context: The caller must hold svms->lock
 *
 * Return: the svm_range found or NULL
 */
struct svm_range *
svm_range_from_addr(struct svm_range_list *svms, unsigned long addr,
                    struct svm_range **parent)
{
        struct interval_tree_node *node;
        struct svm_range *prange;
        struct svm_range *pchild;

        node = interval_tree_iter_first(&svms->objects, addr, addr);
        if (!node)
                return NULL;

        prange = container_of(node, struct svm_range, it_node);
        pr_debug("address 0x%lx prange [0x%lx 0x%lx] node [0x%lx 0x%lx]\n",
                 addr, prange->start, prange->last, node->start, node->last);

        if (addr >= prange->start && addr <= prange->last) {
                if (parent)
                        *parent = prange;
                return prange;
        }
        list_for_each_entry(pchild, &prange->child_list, child_list)
                if (addr >= pchild->start && addr <= pchild->last) {
                        pr_debug("found address 0x%lx pchild [0x%lx 0x%lx]\n",
                                 addr, pchild->start, pchild->last);
                        if (parent)
                                *parent = prange;
                        return pchild;
                }

        return NULL;
}

/* svm_range_best_restore_location - decide the best fault restore location
 * @prange: svm range structure
 * @adev: the GPU on which vm fault happened
 *
 * This is only called when xnack is on, to decide the best location to restore
 * the range mapping after GPU vm fault. Caller uses the best location to do
 * migration if actual loc is not best location, then update GPU page table
 * mapping to the best location.
 *
 * If the preferred loc is accessible by faulting GPU, use preferred loc.
 * If vm fault gpu idx is on range ACCESSIBLE bitmap, best_loc is vm fault gpu
 * If vm fault gpu idx is on range ACCESSIBLE_IN_PLACE bitmap, then
 *    if range actual loc is cpu, best_loc is cpu
 *    if vm fault gpu is on xgmi same hive of range actual loc gpu, best_loc is
 *    range actual loc.
 * Otherwise, GPU no access, best_loc is -1.
 *
 * Return:
 * -1 means vm fault GPU no access
 * 0 for CPU or GPU id
 */
static int32_t
svm_range_best_restore_location(struct svm_range *prange,
                                struct amdgpu_device *adev,
                                int32_t *gpuidx)
{
        struct amdgpu_device *bo_adev, *preferred_adev;
        struct kfd_process *p;
        uint32_t gpuid;
        int r;

        p = container_of(prange->svms, struct kfd_process, svms);

        r = kfd_process_gpuid_from_adev(p, adev, &gpuid, gpuidx);
        if (r < 0) {
                pr_debug("failed to get gpuid from kgd\n");
                return -1;
        }

        if (prange->preferred_loc == gpuid ||
            prange->preferred_loc == KFD_IOCTL_SVM_LOCATION_SYSMEM) {
                return prange->preferred_loc;
        } else if (prange->preferred_loc != KFD_IOCTL_SVM_LOCATION_UNDEFINED) {
                preferred_adev = svm_range_get_adev_by_id(prange,
                                                        prange->preferred_loc);
                if (amdgpu_xgmi_same_hive(adev, preferred_adev))
                        return prange->preferred_loc;
                /* fall through */
        }

        if (test_bit(*gpuidx, prange->bitmap_access))
                return gpuid;

        if (test_bit(*gpuidx, prange->bitmap_aip)) {
                if (!prange->actual_loc)
                        return 0;

                bo_adev = svm_range_get_adev_by_id(prange, prange->actual_loc);
                if (amdgpu_xgmi_same_hive(adev, bo_adev))
                        return prange->actual_loc;
                else
                        return 0;
        }

        return -1;
}

static int
svm_range_get_range_boundaries(struct kfd_process *p, int64_t addr,
                               unsigned long *start, unsigned long *last,
                               bool *is_heap_stack)
{
        struct vm_area_struct *vma;
        struct interval_tree_node *node;
        unsigned long start_limit, end_limit;

        vma = find_vma(p->mm, addr << PAGE_SHIFT);
        if (!vma || (addr << PAGE_SHIFT) < vma->vm_start) {
                pr_debug("VMA does not exist in address [0x%llx]\n", addr);
                return -EFAULT;
        }

        *is_heap_stack = (vma->vm_start <= vma->vm_mm->brk &&
                          vma->vm_end >= vma->vm_mm->start_brk) ||
                         (vma->vm_start <= vma->vm_mm->start_stack &&
                          vma->vm_end >= vma->vm_mm->start_stack);

        start_limit = max(vma->vm_start >> PAGE_SHIFT,
                      (unsigned long)ALIGN_DOWN(addr, 2UL << 8));
        end_limit = min(vma->vm_end >> PAGE_SHIFT,
                    (unsigned long)ALIGN(addr + 1, 2UL << 8));
        /* First range that starts after the fault address */
        node = interval_tree_iter_first(&p->svms.objects, addr + 1, ULONG_MAX);
        if (node) {
                end_limit = min(end_limit, node->start);
                /* Last range that ends before the fault address */
                node = container_of(rb_prev(&node->rb),
                                    struct interval_tree_node, rb);
        } else {
                /* Last range must end before addr because
                 * there was no range after addr
                 */
                node = container_of(rb_last(&p->svms.objects.rb_root),
                                    struct interval_tree_node, rb);
        }
        if (node) {
                if (node->last >= addr) {
                        WARN(1, "Overlap with prev node and page fault addr\n");
                        return -EFAULT;
                }
                start_limit = max(start_limit, node->last + 1);
        }

        *start = start_limit;
        *last = end_limit - 1;

        pr_debug("vma [0x%lx 0x%lx] range [0x%lx 0x%lx] is_heap_stack %d\n",
                 vma->vm_start >> PAGE_SHIFT, vma->vm_end >> PAGE_SHIFT,
                 *start, *last, *is_heap_stack);

        return 0;
}

static int
svm_range_check_vm_userptr(struct kfd_process *p, uint64_t start, uint64_t last,
                           uint64_t *bo_s, uint64_t *bo_l)
{
        struct amdgpu_bo_va_mapping *mapping;
        struct interval_tree_node *node;
        struct amdgpu_bo *bo = NULL;
        unsigned long userptr;
        uint32_t i;
        int r;

        for (i = 0; i < p->n_pdds; i++) {
                struct amdgpu_vm *vm;

                if (!p->pdds[i]->drm_priv)
                        continue;

                vm = drm_priv_to_vm(p->pdds[i]->drm_priv);
                r = amdgpu_bo_reserve(vm->root.bo, false);
                if (r)
                        return r;

                /* Check userptr by searching entire vm->va interval tree */
                node = interval_tree_iter_first(&vm->va, 0, ~0ULL);
                while (node) {
                        mapping = container_of((struct rb_node *)node,
                                               struct amdgpu_bo_va_mapping, rb);
                        bo = mapping->bo_va->base.bo;

                        if (!amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm,
                                                         start << PAGE_SHIFT,
                                                         last << PAGE_SHIFT,
                                                         &userptr)) {
                                node = interval_tree_iter_next(node, 0, ~0ULL);
                                continue;
                        }

                        pr_debug("[0x%llx 0x%llx] already userptr mapped\n",
                                 start, last);
                        if (bo_s && bo_l) {
                                *bo_s = userptr >> PAGE_SHIFT;
                                *bo_l = *bo_s + bo->tbo.ttm->num_pages - 1;
                        }
                        amdgpu_bo_unreserve(vm->root.bo);
                        return -EADDRINUSE;
                }
                amdgpu_bo_unreserve(vm->root.bo);
        }
        return 0;
}

static struct
svm_range *svm_range_create_unregistered_range(struct amdgpu_device *adev,
                                                struct kfd_process *p,
                                                struct mm_struct *mm,
                                                int64_t addr)
{
        struct svm_range *prange = NULL;
        unsigned long start, last;
        uint32_t gpuid, gpuidx;
        bool is_heap_stack;
        uint64_t bo_s = 0;
        uint64_t bo_l = 0;
        int r;

        if (svm_range_get_range_boundaries(p, addr, &start, &last,
                                           &is_heap_stack))
                return NULL;

        r = svm_range_check_vm(p, start, last, &bo_s, &bo_l);
        if (r != -EADDRINUSE)
                r = svm_range_check_vm_userptr(p, start, last, &bo_s, &bo_l);

        if (r == -EADDRINUSE) {
                if (addr >= bo_s && addr <= bo_l)
                        return NULL;

                /* Create one page svm range if 2MB range overlapping */
                start = addr;
                last = addr;
        }

        prange = svm_range_new(&p->svms, start, last, true);
        if (!prange) {
                pr_debug("Failed to create prange in address [0x%llx]\n", addr);
                return NULL;
        }
        if (kfd_process_gpuid_from_adev(p, adev, &gpuid, &gpuidx)) {
                pr_debug("failed to get gpuid from kgd\n");
                svm_range_free(prange, true);
                return NULL;
        }

        if (is_heap_stack)
                prange->preferred_loc = KFD_IOCTL_SVM_LOCATION_SYSMEM;

        svm_range_add_to_svms(prange);
        svm_range_add_notifier_locked(mm, prange);

        return prange;
}

/* svm_range_skip_recover - decide if prange can be recovered
 * @prange: svm range structure
 *
 * GPU vm retry fault handle skip recover the range for cases:
 * 1. prange is on deferred list to be removed after unmap, it is stale fault,
 *    deferred list work will drain the stale fault before free the prange.
 * 2. prange is on deferred list to add interval notifier after split, or
 * 3. prange is child range, it is split from parent prange, recover later
 *    after interval notifier is added.
 *
 * Return: true to skip recover, false to recover
 */
static bool svm_range_skip_recover(struct svm_range *prange)
{
        struct svm_range_list *svms = prange->svms;

        spin_lock(&svms->deferred_list_lock);
        if (list_empty(&prange->deferred_list) &&
            list_empty(&prange->child_list)) {
                spin_unlock(&svms->deferred_list_lock);
                return false;
        }
        spin_unlock(&svms->deferred_list_lock);

        if (prange->work_item.op == SVM_OP_UNMAP_RANGE) {
                pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] unmapped\n",
                         svms, prange, prange->start, prange->last);
                return true;
        }
        if (prange->work_item.op == SVM_OP_ADD_RANGE_AND_MAP ||
            prange->work_item.op == SVM_OP_ADD_RANGE) {
                pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] not added yet\n",
                         svms, prange, prange->start, prange->last);
                return true;
        }
        return false;
}

static void
svm_range_count_fault(struct amdgpu_device *adev, struct kfd_process *p,
                      int32_t gpuidx)
{
        struct kfd_process_device *pdd;

        /* fault is on different page of same range
         * or fault is skipped to recover later
         * or fault is on invalid virtual address
         */
        if (gpuidx == MAX_GPU_INSTANCE) {
                uint32_t gpuid;
                int r;

                r = kfd_process_gpuid_from_adev(p, adev, &gpuid, &gpuidx);
                if (r < 0)
                        return;
        }

        /* fault is recovered
         * or fault cannot recover because GPU no access on the range
         */
        pdd = kfd_process_device_from_gpuidx(p, gpuidx);
        if (pdd)
                WRITE_ONCE(pdd->faults, pdd->faults + 1);
}

static bool
svm_fault_allowed(struct vm_area_struct *vma, bool write_fault)
{
        unsigned long requested = VM_READ;

        if (write_fault)
                requested |= VM_WRITE;

        pr_debug("requested 0x%lx, vma permission flags 0x%lx\n", requested,
                vma->vm_flags);
        return (vma->vm_flags & requested) == requested;
}

int
svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid,
                        uint64_t addr, bool write_fault)
{
        struct mm_struct *mm = NULL;
        struct svm_range_list *svms;
        struct svm_range *prange;
        struct kfd_process *p;
        ktime_t timestamp = ktime_get_boottime();
        int32_t best_loc;
        int32_t gpuidx = MAX_GPU_INSTANCE;
        bool write_locked = false;
        struct vm_area_struct *vma;
        bool migration = false;
        int r = 0;

        if (!KFD_IS_SVM_API_SUPPORTED(adev->kfd.dev)) {
                pr_debug("device does not support SVM\n");
                return -EFAULT;
        }

        p = kfd_lookup_process_by_pasid(pasid);
        if (!p) {
                pr_debug("kfd process not founded pasid 0x%x\n", pasid);
                return 0;
        }
        svms = &p->svms;

        pr_debug("restoring svms 0x%p fault address 0x%llx\n", svms, addr);

        if (atomic_read(&svms->drain_pagefaults)) {
                pr_debug("draining retry fault, drop fault 0x%llx\n", addr);
                r = 0;
                goto out;
        }

        if (!p->xnack_enabled) {
                pr_debug("XNACK not enabled for pasid 0x%x\n", pasid);
                r = -EFAULT;
                goto out;
        }

        /* p->lead_thread is available as kfd_process_wq_release flush the work
         * before releasing task ref.
         */
        mm = get_task_mm(p->lead_thread);
        if (!mm) {
                pr_debug("svms 0x%p failed to get mm\n", svms);
                r = 0;
                goto out;
        }

        mmap_read_lock(mm);
retry_write_locked:
        mutex_lock(&svms->lock);
        prange = svm_range_from_addr(svms, addr, NULL);
        if (!prange) {
                pr_debug("failed to find prange svms 0x%p address [0x%llx]\n",
                         svms, addr);
                if (!write_locked) {
                        /* Need the write lock to create new range with MMU notifier.
                         * Also flush pending deferred work to make sure the interval
                         * tree is up to date before we add a new range
                         */
                        mutex_unlock(&svms->lock);
                        mmap_read_unlock(mm);
                        mmap_write_lock(mm);
                        write_locked = true;
                        goto retry_write_locked;
                }
                prange = svm_range_create_unregistered_range(adev, p, mm, addr);
                if (!prange) {
                        pr_debug("failed to create unregistered range svms 0x%p address [0x%llx]\n",
                                 svms, addr);
                        mmap_write_downgrade(mm);
                        r = -EFAULT;
                        goto out_unlock_svms;
                }
        }
        if (write_locked)
                mmap_write_downgrade(mm);

        mutex_lock(&prange->migrate_mutex);

        if (svm_range_skip_recover(prange)) {
                amdgpu_gmc_filter_faults_remove(adev, addr, pasid);
                r = 0;
                goto out_unlock_range;
        }

        /* skip duplicate vm fault on different pages of same range */
        if (ktime_before(timestamp, ktime_add_ns(prange->validate_timestamp,
                                AMDGPU_SVM_RANGE_RETRY_FAULT_PENDING))) {
                pr_debug("svms 0x%p [0x%lx %lx] already restored\n",
                         svms, prange->start, prange->last);
                r = 0;
                goto out_unlock_range;
        }

        /* __do_munmap removed VMA, return success as we are handling stale
         * retry fault.
         */
        vma = find_vma(mm, addr << PAGE_SHIFT);
        if (!vma || (addr << PAGE_SHIFT) < vma->vm_start) {
                pr_debug("address 0x%llx VMA is removed\n", addr);
                r = 0;
                goto out_unlock_range;
        }

        if (!svm_fault_allowed(vma, write_fault)) {
                pr_debug("fault addr 0x%llx no %s permission\n", addr,
                        write_fault ? "write" : "read");
                r = -EPERM;
                goto out_unlock_range;
        }

        best_loc = svm_range_best_restore_location(prange, adev, &gpuidx);
        if (best_loc == -1) {
                pr_debug("svms %p failed get best restore loc [0x%lx 0x%lx]\n",
                         svms, prange->start, prange->last);
                r = -EACCES;
                goto out_unlock_range;
        }

        pr_debug("svms %p [0x%lx 0x%lx] best restore 0x%x, actual loc 0x%x\n",
                 svms, prange->start, prange->last, best_loc,
                 prange->actual_loc);

        kfd_smi_event_page_fault_start(adev->kfd.dev, p->lead_thread->pid, addr,
                                       write_fault, timestamp);

        if (prange->actual_loc != best_loc) {
                migration = true;
                if (best_loc) {
                        r = svm_migrate_to_vram(prange, best_loc, mm,
                                        KFD_MIGRATE_TRIGGER_PAGEFAULT_GPU);
                        if (r) {
                                pr_debug("svm_migrate_to_vram failed (%d) at %llx, falling back to system memory\n",
                                         r, addr);
                                /* Fallback to system memory if migration to
                                 * VRAM failed
                                 */
                                if (prange->actual_loc)
                                        r = svm_migrate_vram_to_ram(prange, mm,
                                           KFD_MIGRATE_TRIGGER_PAGEFAULT_GPU);
                                else
                                        r = 0;
                        }
                } else {
                        r = svm_migrate_vram_to_ram(prange, mm,
                                        KFD_MIGRATE_TRIGGER_PAGEFAULT_GPU);
                }
                if (r) {
                        pr_debug("failed %d to migrate svms %p [0x%lx 0x%lx]\n",
                                 r, svms, prange->start, prange->last);
                        goto out_unlock_range;
                }
        }

        r = svm_range_validate_and_map(mm, prange, gpuidx, false, false, false);
        if (r)
                pr_debug("failed %d to map svms 0x%p [0x%lx 0x%lx] to gpus\n",
                         r, svms, prange->start, prange->last);

        kfd_smi_event_page_fault_end(adev->kfd.dev, p->lead_thread->pid, addr,
                                     migration);

out_unlock_range:
        mutex_unlock(&prange->migrate_mutex);
out_unlock_svms:
        mutex_unlock(&svms->lock);
        mmap_read_unlock(mm);

        svm_range_count_fault(adev, p, gpuidx);

        mmput(mm);
out:
        kfd_unref_process(p);

        if (r == -EAGAIN) {
                pr_debug("recover vm fault later\n");
                amdgpu_gmc_filter_faults_remove(adev, addr, pasid);
                r = 0;
        }
        return r;
}

void svm_range_list_fini(struct kfd_process *p)
{
        struct svm_range *prange;
        struct svm_range *next;

        pr_debug("pasid 0x%x svms 0x%p\n", p->pasid, &p->svms);

        cancel_delayed_work_sync(&p->svms.restore_work);

        /* Ensure list work is finished before process is destroyed */
        flush_work(&p->svms.deferred_list_work);

        /*
         * Ensure no retry fault comes in afterwards, as page fault handler will
         * not find kfd process and take mm lock to recover fault.
         */
        atomic_inc(&p->svms.drain_pagefaults);
        svm_range_drain_retry_fault(&p->svms);

        list_for_each_entry_safe(prange, next, &p->svms.list, list) {
                svm_range_unlink(prange);
                svm_range_remove_notifier(prange);
                svm_range_free(prange, true);
        }

        mutex_destroy(&p->svms.lock);

        pr_debug("pasid 0x%x svms 0x%p done\n", p->pasid, &p->svms);
}

int svm_range_list_init(struct kfd_process *p)
{
        struct svm_range_list *svms = &p->svms;
        int i;

        svms->objects = RB_ROOT_CACHED;
        mutex_init(&svms->lock);
        INIT_LIST_HEAD(&svms->list);
        atomic_set(&svms->evicted_ranges, 0);
        atomic_set(&svms->drain_pagefaults, 0);
        INIT_DELAYED_WORK(&svms->restore_work, svm_range_restore_work);
        INIT_WORK(&svms->deferred_list_work, svm_range_deferred_list_work);
        INIT_LIST_HEAD(&svms->deferred_range_list);
        INIT_LIST_HEAD(&svms->criu_svm_metadata_list);
        spin_lock_init(&svms->deferred_list_lock);

        for (i = 0; i < p->n_pdds; i++)
                if (KFD_IS_SVM_API_SUPPORTED(p->pdds[i]->dev))
                        bitmap_set(svms->bitmap_supported, i, 1);

        return 0;
}

/**
 * svm_range_check_vm - check if virtual address range mapped already
 * @p: current kfd_process
 * @start: range start address, in pages
 * @last: range last address, in pages
 * @bo_s: mapping start address in pages if address range already mapped
 * @bo_l: mapping last address in pages if address range already mapped
 *
 * The purpose is to avoid virtual address ranges already allocated by
 * kfd_ioctl_alloc_memory_of_gpu ioctl.
 * It looks for each pdd in the kfd_process.
 *
 * Context: Process context
 *
 * Return 0 - OK, if the range is not mapped.
 * Otherwise error code:
 * -EADDRINUSE - if address is mapped already by kfd_ioctl_alloc_memory_of_gpu
 * -ERESTARTSYS - A wait for the buffer to become unreserved was interrupted by
 * a signal. Release all buffer reservations and return to user-space.
 */
static int
svm_range_check_vm(struct kfd_process *p, uint64_t start, uint64_t last,
                   uint64_t *bo_s, uint64_t *bo_l)
{
        struct amdgpu_bo_va_mapping *mapping;
        struct interval_tree_node *node;
        uint32_t i;
        int r;

        for (i = 0; i < p->n_pdds; i++) {
                struct amdgpu_vm *vm;

                if (!p->pdds[i]->drm_priv)
                        continue;

                vm = drm_priv_to_vm(p->pdds[i]->drm_priv);
                r = amdgpu_bo_reserve(vm->root.bo, false);
                if (r)
                        return r;

                node = interval_tree_iter_first(&vm->va, start, last);
                if (node) {
                        pr_debug("range [0x%llx 0x%llx] already TTM mapped\n",
                                 start, last);
                        mapping = container_of((struct rb_node *)node,
                                               struct amdgpu_bo_va_mapping, rb);
                        if (bo_s && bo_l) {
                                *bo_s = mapping->start;
                                *bo_l = mapping->last;
                        }
                        amdgpu_bo_unreserve(vm->root.bo);
                        return -EADDRINUSE;
                }
                amdgpu_bo_unreserve(vm->root.bo);
        }

        return 0;
}

/**
 * svm_range_is_valid - check if virtual address range is valid
 * @p: current kfd_process
 * @start: range start address, in pages
 * @size: range size, in pages
 *
 * Valid virtual address range means it belongs to one or more VMAs
 *
 * Context: Process context
 *
 * Return:
 *  0 - OK, otherwise error code
 */
static int
svm_range_is_valid(struct kfd_process *p, uint64_t start, uint64_t size)
{
        const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP;
        struct vm_area_struct *vma;
        unsigned long end;
        unsigned long start_unchg = start;

        start <<= PAGE_SHIFT;
        end = start + (size << PAGE_SHIFT);
        do {
                vma = find_vma(p->mm, start);
                if (!vma || start < vma->vm_start ||
                    (vma->vm_flags & device_vma))
                        return -EFAULT;
                start = min(end, vma->vm_end);
        } while (start < end);

        return svm_range_check_vm(p, start_unchg, (end - 1) >> PAGE_SHIFT, NULL,
                                  NULL);
}

/**
 * svm_range_best_prefetch_location - decide the best prefetch location
 * @prange: svm range structure
 *
 * For xnack off:
 * If range map to single GPU, the best prefetch location is prefetch_loc, which
 * can be CPU or GPU.
 *
 * If range is ACCESS or ACCESS_IN_PLACE by mGPUs, only if mGPU connection on
 * XGMI same hive, the best prefetch location is prefetch_loc GPU, othervise
 * the best prefetch location is always CPU, because GPU can not have coherent
 * mapping VRAM of other GPUs even with large-BAR PCIe connection.
 *
 * For xnack on:
 * If range is not ACCESS_IN_PLACE by mGPUs, the best prefetch location is
 * prefetch_loc, other GPU access will generate vm fault and trigger migration.
 *
 * If range is ACCESS_IN_PLACE by mGPUs, only if mGPU connection on XGMI same
 * hive, the best prefetch location is prefetch_loc GPU, otherwise the best
 * prefetch location is always CPU.
 *
 * Context: Process context
 *
 * Return:
 * 0 for CPU or GPU id
 */
static uint32_t
svm_range_best_prefetch_location(struct svm_range *prange)
{
        DECLARE_BITMAP(bitmap, MAX_GPU_INSTANCE);
        uint32_t best_loc = prange->prefetch_loc;
        struct kfd_process_device *pdd;
        struct amdgpu_device *bo_adev;
        struct kfd_process *p;
        uint32_t gpuidx;

        p = container_of(prange->svms, struct kfd_process, svms);

        if (!best_loc || best_loc == KFD_IOCTL_SVM_LOCATION_UNDEFINED)
                goto out;

        bo_adev = svm_range_get_adev_by_id(prange, best_loc);
        if (!bo_adev) {
                WARN_ONCE(1, "failed to get device by id 0x%x\n", best_loc);
                best_loc = 0;
                goto out;
        }

        if (p->xnack_enabled)
                bitmap_copy(bitmap, prange->bitmap_aip, MAX_GPU_INSTANCE);
        else
                bitmap_or(bitmap, prange->bitmap_access, prange->bitmap_aip,
                          MAX_GPU_INSTANCE);

        for_each_set_bit(gpuidx, bitmap, MAX_GPU_INSTANCE) {
                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to get device by idx 0x%x\n", gpuidx);
                        continue;
                }

                if (pdd->dev->adev == bo_adev)
                        continue;

                if (!amdgpu_xgmi_same_hive(pdd->dev->adev, bo_adev)) {
                        best_loc = 0;
                        break;
                }
        }

out:
        pr_debug("xnack %d svms 0x%p [0x%lx 0x%lx] best loc 0x%x\n",
                 p->xnack_enabled, &p->svms, prange->start, prange->last,
                 best_loc);

        return best_loc;
}

/* FIXME: This is a workaround for page locking bug when some pages are
 * invalid during migration to VRAM
 */
void svm_range_prefault(struct svm_range *prange, struct mm_struct *mm,
                        void *owner)
{
        struct hmm_range *hmm_range;
        int r;

        if (prange->validated_once)
                return;

        r = amdgpu_hmm_range_get_pages(&prange->notifier, mm, NULL,
                                       prange->start << PAGE_SHIFT,
                                       prange->npages, &hmm_range,
                                       false, true, owner);
        if (!r) {
                amdgpu_hmm_range_get_pages_done(hmm_range);
                prange->validated_once = true;
        }
}

/* svm_range_trigger_migration - start page migration if prefetch loc changed
 * @mm: current process mm_struct
 * @prange: svm range structure
 * @migrated: output, true if migration is triggered
 *
 * If range perfetch_loc is GPU, actual loc is cpu 0, then migrate the range
 * from ram to vram.
 * If range prefetch_loc is cpu 0, actual loc is GPU, then migrate the range
 * from vram to ram.
 *
 * If GPU vm fault retry is not enabled, migration interact with MMU notifier
 * and restore work:
 * 1. migrate_vma_setup invalidate pages, MMU notifier callback svm_range_evict
 *    stops all queues, schedule restore work
 * 2. svm_range_restore_work wait for migration is done by
 *    a. svm_range_validate_vram takes prange->migrate_mutex
 *    b. svm_range_validate_ram HMM get pages wait for CPU fault handle returns
 * 3. restore work update mappings of GPU, resume all queues.
 *
 * Context: Process context
 *
 * Return:
 * 0 - OK, otherwise - error code of migration
 */
static int
svm_range_trigger_migration(struct mm_struct *mm, struct svm_range *prange,
                            bool *migrated)
{
        uint32_t best_loc;
        int r = 0;

        *migrated = false;
        best_loc = svm_range_best_prefetch_location(prange);

        if (best_loc == KFD_IOCTL_SVM_LOCATION_UNDEFINED ||
            best_loc == prange->actual_loc)
                return 0;

        if (!best_loc) {
                r = svm_migrate_vram_to_ram(prange, mm, KFD_MIGRATE_TRIGGER_PREFETCH);
                *migrated = !r;
                return r;
        }

        r = svm_migrate_to_vram(prange, best_loc, mm, KFD_MIGRATE_TRIGGER_PREFETCH);
        *migrated = !r;

        return r;
}

int svm_range_schedule_evict_svm_bo(struct amdgpu_amdkfd_fence *fence)
{
        if (!fence)
                return -EINVAL;

        if (dma_fence_is_signaled(&fence->base))
                return 0;

        if (fence->svm_bo) {
                WRITE_ONCE(fence->svm_bo->evicting, 1);
                schedule_work(&fence->svm_bo->eviction_work);
        }

        return 0;
}

static void svm_range_evict_svm_bo_worker(struct work_struct *work)
{
        struct svm_range_bo *svm_bo;
        struct kfd_process *p;
        struct mm_struct *mm;
        int r = 0;

        svm_bo = container_of(work, struct svm_range_bo, eviction_work);
        if (!svm_bo_ref_unless_zero(svm_bo))
                return; /* svm_bo was freed while eviction was pending */

        /* svm_range_bo_release destroys this worker thread. So during
         * the lifetime of this thread, kfd_process and mm will be valid.
         */
        p = container_of(svm_bo->svms, struct kfd_process, svms);
        mm = p->mm;
        if (!mm)
                return;

        mmap_read_lock(mm);
        spin_lock(&svm_bo->list_lock);
        while (!list_empty(&svm_bo->range_list) && !r) {
                struct svm_range *prange =
                                list_first_entry(&svm_bo->range_list,
                                                struct svm_range, svm_bo_list);
                int retries = 3;

                list_del_init(&prange->svm_bo_list);
                spin_unlock(&svm_bo->list_lock);

                pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms,
                         prange->start, prange->last);

                mutex_lock(&prange->migrate_mutex);
                do {
                        r = svm_migrate_vram_to_ram(prange,
                                                svm_bo->eviction_fence->mm,
                                                KFD_MIGRATE_TRIGGER_TTM_EVICTION);
                } while (!r && prange->actual_loc && --retries);

                if (!r && prange->actual_loc)
                        pr_info_once("Migration failed during eviction");

                if (!prange->actual_loc) {
                        mutex_lock(&prange->lock);
                        prange->svm_bo = NULL;
                        mutex_unlock(&prange->lock);
                }
                mutex_unlock(&prange->migrate_mutex);

                spin_lock(&svm_bo->list_lock);
        }
        spin_unlock(&svm_bo->list_lock);
        mmap_read_unlock(mm);

        dma_fence_signal(&svm_bo->eviction_fence->base);

        /* This is the last reference to svm_bo, after svm_range_vram_node_free
         * has been called in svm_migrate_vram_to_ram
         */
        WARN_ONCE(!r && kref_read(&svm_bo->kref) != 1, "This was not the last reference\n");
        svm_range_bo_unref(svm_bo);
}

static int
svm_range_set_attr(struct kfd_process *p, struct mm_struct *mm,
                   uint64_t start, uint64_t size, uint32_t nattr,
                   struct kfd_ioctl_svm_attribute *attrs)
{
        struct amdkfd_process_info *process_info = p->kgd_process_info;
        struct list_head update_list;
        struct list_head insert_list;
        struct list_head remove_list;
        struct svm_range_list *svms;
        struct svm_range *prange;
        struct svm_range *next;
        bool update_mapping = false;
        bool flush_tlb;
        int r = 0;

        pr_debug("pasid 0x%x svms 0x%p [0x%llx 0x%llx] pages 0x%llx\n",
                 p->pasid, &p->svms, start, start + size - 1, size);

        r = svm_range_check_attr(p, nattr, attrs);
        if (r)
                return r;

        svms = &p->svms;

        mutex_lock(&process_info->lock);

        svm_range_list_lock_and_flush_work(svms, mm);

        r = svm_range_is_valid(p, start, size);
        if (r) {
                pr_debug("invalid range r=%d\n", r);
                mmap_write_unlock(mm);
                goto out;
        }

        mutex_lock(&svms->lock);

        /* Add new range and split existing ranges as needed */
        r = svm_range_add(p, start, size, nattr, attrs, &update_list,
                          &insert_list, &remove_list);
        if (r) {
                mutex_unlock(&svms->lock);
                mmap_write_unlock(mm);
                goto out;
        }
        /* Apply changes as a transaction */
        list_for_each_entry_safe(prange, next, &insert_list, list) {
                svm_range_add_to_svms(prange);
                svm_range_add_notifier_locked(mm, prange);
        }
        list_for_each_entry(prange, &update_list, update_list) {
                svm_range_apply_attrs(p, prange, nattr, attrs, &update_mapping);
                /* TODO: unmap ranges from GPU that lost access */
        }
        list_for_each_entry_safe(prange, next, &remove_list, update_list) {
                pr_debug("unlink old 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                         prange->svms, prange, prange->start,
                         prange->last);
                svm_range_unlink(prange);
                svm_range_remove_notifier(prange);
                svm_range_free(prange, false);
        }

        mmap_write_downgrade(mm);
        /* Trigger migrations and revalidate and map to GPUs as needed. If
         * this fails we may be left with partially completed actions. There
         * is no clean way of rolling back to the previous state in such a
         * case because the rollback wouldn't be guaranteed to work either.
         */
        list_for_each_entry(prange, &update_list, update_list) {
                bool migrated;

                mutex_lock(&prange->migrate_mutex);

                r = svm_range_trigger_migration(mm, prange, &migrated);
                if (r)
                        goto out_unlock_range;

                if (migrated && (!p->xnack_enabled ||
                    (prange->flags & KFD_IOCTL_SVM_FLAG_GPU_ALWAYS_MAPPED)) &&
                    prange->mapped_to_gpu) {
                        pr_debug("restore_work will update mappings of GPUs\n");
                        mutex_unlock(&prange->migrate_mutex);
                        continue;
                }

                if (!migrated && !update_mapping) {
                        mutex_unlock(&prange->migrate_mutex);
                        continue;
                }

                flush_tlb = !migrated && update_mapping && prange->mapped_to_gpu;

                r = svm_range_validate_and_map(mm, prange, MAX_GPU_INSTANCE,
                                               true, true, flush_tlb);
                if (r)
                        pr_debug("failed %d to map svm range\n", r);

out_unlock_range:
                mutex_unlock(&prange->migrate_mutex);
                if (r)
                        break;
        }

        svm_range_debug_dump(svms);

        mutex_unlock(&svms->lock);
        mmap_read_unlock(mm);
out:
        mutex_unlock(&process_info->lock);

        pr_debug("pasid 0x%x svms 0x%p [0x%llx 0x%llx] done, r=%d\n", p->pasid,
                 &p->svms, start, start + size - 1, r);

        return r;
}

static int
svm_range_get_attr(struct kfd_process *p, struct mm_struct *mm,
                   uint64_t start, uint64_t size, uint32_t nattr,
                   struct kfd_ioctl_svm_attribute *attrs)
{
        DECLARE_BITMAP(bitmap_access, MAX_GPU_INSTANCE);
        DECLARE_BITMAP(bitmap_aip, MAX_GPU_INSTANCE);
        bool get_preferred_loc = false;
        bool get_prefetch_loc = false;
        bool get_granularity = false;
        bool get_accessible = false;
        bool get_flags = false;
        uint64_t last = start + size - 1UL;
        uint8_t granularity = 0xff;
        struct interval_tree_node *node;
        struct svm_range_list *svms;
        struct svm_range *prange;
        uint32_t prefetch_loc = KFD_IOCTL_SVM_LOCATION_UNDEFINED;
        uint32_t location = KFD_IOCTL_SVM_LOCATION_UNDEFINED;
        uint32_t flags_and = 0xffffffff;
        uint32_t flags_or = 0;
        int gpuidx;
        uint32_t i;
        int r = 0;

        pr_debug("svms 0x%p [0x%llx 0x%llx] nattr 0x%x\n", &p->svms, start,
                 start + size - 1, nattr);

        /* Flush pending deferred work to avoid racing with deferred actions from
         * previous memory map changes (e.g. munmap). Concurrent memory map changes
         * can still race with get_attr because we don't hold the mmap lock. But that
         * would be a race condition in the application anyway, and undefined
         * behaviour is acceptable in that case.
         */
        flush_work(&p->svms.deferred_list_work);

        mmap_read_lock(mm);
        r = svm_range_is_valid(p, start, size);
        mmap_read_unlock(mm);
        if (r) {
                pr_debug("invalid range r=%d\n", r);
                return r;
        }

        for (i = 0; i < nattr; i++) {
                switch (attrs[i].type) {
                case KFD_IOCTL_SVM_ATTR_PREFERRED_LOC:
                        get_preferred_loc = true;
                        break;
                case KFD_IOCTL_SVM_ATTR_PREFETCH_LOC:
                        get_prefetch_loc = true;
                        break;
                case KFD_IOCTL_SVM_ATTR_ACCESS:
                        get_accessible = true;
                        break;
                case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
                case KFD_IOCTL_SVM_ATTR_CLR_FLAGS:
                        get_flags = true;
                        break;
                case KFD_IOCTL_SVM_ATTR_GRANULARITY:
                        get_granularity = true;
                        break;
                case KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE:
                case KFD_IOCTL_SVM_ATTR_NO_ACCESS:
                        fallthrough;
                default:
                        pr_debug("get invalid attr type 0x%x\n", attrs[i].type);
                        return -EINVAL;
                }
        }

        svms = &p->svms;

        mutex_lock(&svms->lock);

        node = interval_tree_iter_first(&svms->objects, start, last);
        if (!node) {
                pr_debug("range attrs not found return default values\n");
                svm_range_set_default_attributes(&location, &prefetch_loc,
                                                 &granularity, &flags_and);
                flags_or = flags_and;
                if (p->xnack_enabled)
                        bitmap_copy(bitmap_access, svms->bitmap_supported,
                                    MAX_GPU_INSTANCE);
                else
                        bitmap_zero(bitmap_access, MAX_GPU_INSTANCE);
                bitmap_zero(bitmap_aip, MAX_GPU_INSTANCE);
                goto fill_values;
        }
        bitmap_copy(bitmap_access, svms->bitmap_supported, MAX_GPU_INSTANCE);
        bitmap_copy(bitmap_aip, svms->bitmap_supported, MAX_GPU_INSTANCE);

        while (node) {
                struct interval_tree_node *next;

                prange = container_of(node, struct svm_range, it_node);
                next = interval_tree_iter_next(node, start, last);

                if (get_preferred_loc) {
                        if (prange->preferred_loc ==
                                        KFD_IOCTL_SVM_LOCATION_UNDEFINED ||
                            (location != KFD_IOCTL_SVM_LOCATION_UNDEFINED &&
                             location != prange->preferred_loc)) {
                                location = KFD_IOCTL_SVM_LOCATION_UNDEFINED;
                                get_preferred_loc = false;
                        } else {
                                location = prange->preferred_loc;
                        }
                }
                if (get_prefetch_loc) {
                        if (prange->prefetch_loc ==
                                        KFD_IOCTL_SVM_LOCATION_UNDEFINED ||
                            (prefetch_loc != KFD_IOCTL_SVM_LOCATION_UNDEFINED &&
                             prefetch_loc != prange->prefetch_loc)) {
                                prefetch_loc = KFD_IOCTL_SVM_LOCATION_UNDEFINED;
                                get_prefetch_loc = false;
                        } else {
                                prefetch_loc = prange->prefetch_loc;
                        }
                }
                if (get_accessible) {
                        bitmap_and(bitmap_access, bitmap_access,
                                   prange->bitmap_access, MAX_GPU_INSTANCE);
                        bitmap_and(bitmap_aip, bitmap_aip,
                                   prange->bitmap_aip, MAX_GPU_INSTANCE);
                }
                if (get_flags) {
                        flags_and &= prange->flags;
                        flags_or |= prange->flags;
                }

                if (get_granularity && prange->granularity < granularity)
                        granularity = prange->granularity;

                node = next;
        }
fill_values:
        mutex_unlock(&svms->lock);

        for (i = 0; i < nattr; i++) {
                switch (attrs[i].type) {
                case KFD_IOCTL_SVM_ATTR_PREFERRED_LOC:
                        attrs[i].value = location;
                        break;
                case KFD_IOCTL_SVM_ATTR_PREFETCH_LOC:
                        attrs[i].value = prefetch_loc;
                        break;
                case KFD_IOCTL_SVM_ATTR_ACCESS:
                        gpuidx = kfd_process_gpuidx_from_gpuid(p,
                                                               attrs[i].value);
                        if (gpuidx < 0) {
                                pr_debug("invalid gpuid %x\n", attrs[i].value);
                                return -EINVAL;
                        }
                        if (test_bit(gpuidx, bitmap_access))
                                attrs[i].type = KFD_IOCTL_SVM_ATTR_ACCESS;
                        else if (test_bit(gpuidx, bitmap_aip))
                                attrs[i].type =
                                        KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE;
                        else
                                attrs[i].type = KFD_IOCTL_SVM_ATTR_NO_ACCESS;
                        break;
                case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
                        attrs[i].value = flags_and;
                        break;
                case KFD_IOCTL_SVM_ATTR_CLR_FLAGS:
                        attrs[i].value = ~flags_or;
                        break;
                case KFD_IOCTL_SVM_ATTR_GRANULARITY:
                        attrs[i].value = (uint32_t)granularity;
                        break;
                }
        }

        return 0;
}

int kfd_criu_resume_svm(struct kfd_process *p)
{
        struct kfd_ioctl_svm_attribute *set_attr_new, *set_attr = NULL;
        int nattr_common = 4, nattr_accessibility = 1;
        struct criu_svm_metadata *criu_svm_md = NULL;
        struct svm_range_list *svms = &p->svms;
        struct criu_svm_metadata *next = NULL;
        uint32_t set_flags = 0xffffffff;
        int i, j, num_attrs, ret = 0;
        uint64_t set_attr_size;
        struct mm_struct *mm;

        if (list_empty(&svms->criu_svm_metadata_list)) {
                pr_debug("No SVM data from CRIU restore stage 2\n");
                return ret;
        }

        mm = get_task_mm(p->lead_thread);
        if (!mm) {
                pr_err("failed to get mm for the target process\n");
                return -ESRCH;
        }

        num_attrs = nattr_common + (nattr_accessibility * p->n_pdds);

        i = j = 0;
        list_for_each_entry(criu_svm_md, &svms->criu_svm_metadata_list, list) {
                pr_debug("criu_svm_md[%d]\n\tstart: 0x%llx size: 0x%llx (npages)\n",
                         i, criu_svm_md->data.start_addr, criu_svm_md->data.size);

                for (j = 0; j < num_attrs; j++) {
                        pr_debug("\ncriu_svm_md[%d]->attrs[%d].type : 0x%x\ncriu_svm_md[%d]->attrs[%d].value : 0x%x\n",
                                 i, j, criu_svm_md->data.attrs[j].type,
                                 i, j, criu_svm_md->data.attrs[j].value);
                        switch (criu_svm_md->data.attrs[j].type) {
                        /* During Checkpoint operation, the query for
                         * KFD_IOCTL_SVM_ATTR_PREFETCH_LOC attribute might
                         * return KFD_IOCTL_SVM_LOCATION_UNDEFINED if they were
                         * not used by the range which was checkpointed. Care
                         * must be taken to not restore with an invalid value
                         * otherwise the gpuidx value will be invalid and
                         * set_attr would eventually fail so just replace those
                         * with another dummy attribute such as
                         * KFD_IOCTL_SVM_ATTR_SET_FLAGS.
                         */
                        case KFD_IOCTL_SVM_ATTR_PREFETCH_LOC:
                                if (criu_svm_md->data.attrs[j].value ==
                                    KFD_IOCTL_SVM_LOCATION_UNDEFINED) {
                                        criu_svm_md->data.attrs[j].type =
                                                KFD_IOCTL_SVM_ATTR_SET_FLAGS;
                                        criu_svm_md->data.attrs[j].value = 0;
                                }
                                break;
                        case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
                                set_flags = criu_svm_md->data.attrs[j].value;
                                break;
                        default:
                                break;
                        }
                }

                /* CLR_FLAGS is not available via get_attr during checkpoint but
                 * it needs to be inserted before restoring the ranges so
                 * allocate extra space for it before calling set_attr
                 */
                set_attr_size = sizeof(struct kfd_ioctl_svm_attribute) *
                                                (num_attrs + 1);
                set_attr_new = krealloc(set_attr, set_attr_size,
                                            GFP_KERNEL);
                if (!set_attr_new) {
                        ret = -ENOMEM;
                        goto exit;
                }
                set_attr = set_attr_new;

                memcpy(set_attr, criu_svm_md->data.attrs, num_attrs *
                                        sizeof(struct kfd_ioctl_svm_attribute));
                set_attr[num_attrs].type = KFD_IOCTL_SVM_ATTR_CLR_FLAGS;
                set_attr[num_attrs].value = ~set_flags;

                ret = svm_range_set_attr(p, mm, criu_svm_md->data.start_addr,
                                         criu_svm_md->data.size, num_attrs + 1,
                                         set_attr);
                if (ret) {
                        pr_err("CRIU: failed to set range attributes\n");
                        goto exit;
                }

                i++;
        }
exit:
        kfree(set_attr);
        list_for_each_entry_safe(criu_svm_md, next, &svms->criu_svm_metadata_list, list) {
                pr_debug("freeing criu_svm_md[]\n\tstart: 0x%llx\n",
                                                criu_svm_md->data.start_addr);
                kfree(criu_svm_md);
        }

        mmput(mm);
        return ret;

}

int kfd_criu_restore_svm(struct kfd_process *p,
                         uint8_t __user *user_priv_ptr,
                         uint64_t *priv_data_offset,
                         uint64_t max_priv_data_size)
{
        uint64_t svm_priv_data_size, svm_object_md_size, svm_attrs_size;
        int nattr_common = 4, nattr_accessibility = 1;
        struct criu_svm_metadata *criu_svm_md = NULL;
        struct svm_range_list *svms = &p->svms;
        uint32_t num_devices;
        int ret = 0;

        num_devices = p->n_pdds;
        /* Handle one SVM range object at a time, also the number of gpus are
         * assumed to be same on the restore node, checking must be done while
         * evaluating the topology earlier
         */

        svm_attrs_size = sizeof(struct kfd_ioctl_svm_attribute) *
                (nattr_common + nattr_accessibility * num_devices);
        svm_object_md_size = sizeof(struct criu_svm_metadata) + svm_attrs_size;

        svm_priv_data_size = sizeof(struct kfd_criu_svm_range_priv_data) +
                                                                svm_attrs_size;

        criu_svm_md = kzalloc(svm_object_md_size, GFP_KERNEL);
        if (!criu_svm_md) {
                pr_err("failed to allocate memory to store svm metadata\n");
                return -ENOMEM;
        }
        if (*priv_data_offset + svm_priv_data_size > max_priv_data_size) {
                ret = -EINVAL;
                goto exit;
        }

        ret = copy_from_user(&criu_svm_md->data, user_priv_ptr + *priv_data_offset,
                             svm_priv_data_size);
        if (ret) {
                ret = -EFAULT;
                goto exit;
        }
        *priv_data_offset += svm_priv_data_size;

        list_add_tail(&criu_svm_md->list, &svms->criu_svm_metadata_list);

        return 0;


exit:
        kfree(criu_svm_md);
        return ret;
}

int svm_range_get_info(struct kfd_process *p, uint32_t *num_svm_ranges,
                       uint64_t *svm_priv_data_size)
{
        uint64_t total_size, accessibility_size, common_attr_size;
        int nattr_common = 4, nattr_accessibility = 1;
        int num_devices = p->n_pdds;
        struct svm_range_list *svms;
        struct svm_range *prange;
        uint32_t count = 0;

        *svm_priv_data_size = 0;

        svms = &p->svms;
        if (!svms)
                return -EINVAL;

        mutex_lock(&svms->lock);
        list_for_each_entry(prange, &svms->list, list) {
                pr_debug("prange: 0x%p start: 0x%lx\t npages: 0x%llx\t end: 0x%llx\n",
                         prange, prange->start, prange->npages,
                         prange->start + prange->npages - 1);
                count++;
        }
        mutex_unlock(&svms->lock);

        *num_svm_ranges = count;
        /* Only the accessbility attributes need to be queried for all the gpus
         * individually, remaining ones are spanned across the entire process
         * regardless of the various gpu nodes. Of the remaining attributes,
         * KFD_IOCTL_SVM_ATTR_CLR_FLAGS need not be saved.
         *
         * KFD_IOCTL_SVM_ATTR_PREFERRED_LOC
         * KFD_IOCTL_SVM_ATTR_PREFETCH_LOC
         * KFD_IOCTL_SVM_ATTR_SET_FLAGS
         * KFD_IOCTL_SVM_ATTR_GRANULARITY
         *
         * ** ACCESSBILITY ATTRIBUTES **
         * (Considered as one, type is altered during query, value is gpuid)
         * KFD_IOCTL_SVM_ATTR_ACCESS
         * KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE
         * KFD_IOCTL_SVM_ATTR_NO_ACCESS
         */
        if (*num_svm_ranges > 0) {
                common_attr_size = sizeof(struct kfd_ioctl_svm_attribute) *
                        nattr_common;
                accessibility_size = sizeof(struct kfd_ioctl_svm_attribute) *
                        nattr_accessibility * num_devices;

                total_size = sizeof(struct kfd_criu_svm_range_priv_data) +
                        common_attr_size + accessibility_size;

                *svm_priv_data_size = *num_svm_ranges * total_size;
        }

        pr_debug("num_svm_ranges %u total_priv_size %llu\n", *num_svm_ranges,
                 *svm_priv_data_size);
        return 0;
}

int kfd_criu_checkpoint_svm(struct kfd_process *p,
                            uint8_t __user *user_priv_data,
                            uint64_t *priv_data_offset)
{
        struct kfd_criu_svm_range_priv_data *svm_priv = NULL;
        struct kfd_ioctl_svm_attribute *query_attr = NULL;
        uint64_t svm_priv_data_size, query_attr_size = 0;
        int index, nattr_common = 4, ret = 0;
        struct svm_range_list *svms;
        int num_devices = p->n_pdds;
        struct svm_range *prange;
        struct mm_struct *mm;

        svms = &p->svms;
        if (!svms)
                return -EINVAL;

        mm = get_task_mm(p->lead_thread);
        if (!mm) {
                pr_err("failed to get mm for the target process\n");
                return -ESRCH;
        }

        query_attr_size = sizeof(struct kfd_ioctl_svm_attribute) *
                                (nattr_common + num_devices);

        query_attr = kzalloc(query_attr_size, GFP_KERNEL);
        if (!query_attr) {
                ret = -ENOMEM;
                goto exit;
        }

        query_attr[0].type = KFD_IOCTL_SVM_ATTR_PREFERRED_LOC;
        query_attr[1].type = KFD_IOCTL_SVM_ATTR_PREFETCH_LOC;
        query_attr[2].type = KFD_IOCTL_SVM_ATTR_SET_FLAGS;
        query_attr[3].type = KFD_IOCTL_SVM_ATTR_GRANULARITY;

        for (index = 0; index < num_devices; index++) {
                struct kfd_process_device *pdd = p->pdds[index];

                query_attr[index + nattr_common].type =
                        KFD_IOCTL_SVM_ATTR_ACCESS;
                query_attr[index + nattr_common].value = pdd->user_gpu_id;
        }

        svm_priv_data_size = sizeof(*svm_priv) + query_attr_size;

        svm_priv = kzalloc(svm_priv_data_size, GFP_KERNEL);
        if (!svm_priv) {
                ret = -ENOMEM;
                goto exit_query;
        }

        index = 0;
        list_for_each_entry(prange, &svms->list, list) {

                svm_priv->object_type = KFD_CRIU_OBJECT_TYPE_SVM_RANGE;
                svm_priv->start_addr = prange->start;
                svm_priv->size = prange->npages;
                memcpy(&svm_priv->attrs, query_attr, query_attr_size);
                pr_debug("CRIU: prange: 0x%p start: 0x%lx\t npages: 0x%llx end: 0x%llx\t size: 0x%llx\n",
                         prange, prange->start, prange->npages,
                         prange->start + prange->npages - 1,
                         prange->npages * PAGE_SIZE);

                ret = svm_range_get_attr(p, mm, svm_priv->start_addr,
                                         svm_priv->size,
                                         (nattr_common + num_devices),
                                         svm_priv->attrs);
                if (ret) {
                        pr_err("CRIU: failed to obtain range attributes\n");
                        goto exit_priv;
                }

                if (copy_to_user(user_priv_data + *priv_data_offset, svm_priv,
                                 svm_priv_data_size)) {
                        pr_err("Failed to copy svm priv to user\n");
                        ret = -EFAULT;
                        goto exit_priv;
                }

                *priv_data_offset += svm_priv_data_size;

        }


exit_priv:
        kfree(svm_priv);
exit_query:
        kfree(query_attr);
exit:
        mmput(mm);
        return ret;
}

int
svm_ioctl(struct kfd_process *p, enum kfd_ioctl_svm_op op, uint64_t start,
          uint64_t size, uint32_t nattrs, struct kfd_ioctl_svm_attribute *attrs)
{
        struct mm_struct *mm = current->mm;
        int r;

        start >>= PAGE_SHIFT;
        size >>= PAGE_SHIFT;

        switch (op) {
        case KFD_IOCTL_SVM_OP_SET_ATTR:
                r = svm_range_set_attr(p, mm, start, size, nattrs, attrs);
                break;
        case KFD_IOCTL_SVM_OP_GET_ATTR:
                r = svm_range_get_attr(p, mm, start, size, nattrs, attrs);
                break;
        default:
                r = EINVAL;
                break;
        }

        return r;
}