nouveau/hmm: support mapping large sysmem pages

Nouveau currently only supports mapping PAGE_SIZE sized pages of system
memory when shared virtual memory (SVM) is enabled. Use the new
hmm_pfn_to_map_order() function to support mapping system memory pages
that are PMD_SIZE.

Link: https://lore.kernel.org/r/20200701225352.9649-5-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
index 665dede..c5f8ca6 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -514,38 +514,57 @@ static const struct mmu_interval_notifier_ops nouveau_svm_mni_ops = {
 };
 
 static void nouveau_hmm_convert_pfn(struct nouveau_drm *drm,
-                                   struct hmm_range *range, u64 *ioctl_addr)
+                                   struct hmm_range *range,
+                                   struct nouveau_pfnmap_args *args)
 {
        struct page *page;
 
        /*
-        * The ioctl_addr prepared here is passed through nvif_object_ioctl()
+        * The address prepared here is passed through nvif_object_ioctl()
         * to an eventual DMA map in something like gp100_vmm_pgt_pfn()
         *
         * This is all just encoding the internal hmm representation into a
         * different nouveau internal representation.
         */
        if (!(range->hmm_pfns[0] & HMM_PFN_VALID)) {
-               ioctl_addr[0] = 0;
+               args->p.phys[0] = 0;
                return;
        }
 
        page = hmm_pfn_to_page(range->hmm_pfns[0]);
+       /*
+        * Only map compound pages to the GPU if the CPU is also mapping the
+        * page as a compound page. Otherwise, the PTE protections might not be
+        * consistent (e.g., CPU only maps part of a compound page).
+        * Note that the underlying page might still be larger than the
+        * CPU mapping (e.g., a PUD sized compound page partially mapped with
+        * a PMD sized page table entry).
+        */
+       if (hmm_pfn_to_map_order(range->hmm_pfns[0])) {
+               unsigned long addr = args->p.addr;
+
+               args->p.page = hmm_pfn_to_map_order(range->hmm_pfns[0]) +
+                               PAGE_SHIFT;
+               args->p.size = 1UL << args->p.page;
+               args->p.addr &= ~(args->p.size - 1);
+               page -= (addr - args->p.addr) >> PAGE_SHIFT;
+       }
        if (is_device_private_page(page))
-               ioctl_addr[0] = nouveau_dmem_page_addr(page) |
+               args->p.phys[0] = nouveau_dmem_page_addr(page) |
                                NVIF_VMM_PFNMAP_V0_V |
                                NVIF_VMM_PFNMAP_V0_VRAM;
        else
-               ioctl_addr[0] = page_to_phys(page) |
+               args->p.phys[0] = page_to_phys(page) |
                                NVIF_VMM_PFNMAP_V0_V |
                                NVIF_VMM_PFNMAP_V0_HOST;
        if (range->hmm_pfns[0] & HMM_PFN_WRITE)
-               ioctl_addr[0] |= NVIF_VMM_PFNMAP_V0_W;
+               args->p.phys[0] |= NVIF_VMM_PFNMAP_V0_W;
 }
 
 static int nouveau_range_fault(struct nouveau_svmm *svmm,
-                              struct nouveau_drm *drm, void *data, u32 size,
-                              u64 *ioctl_addr, unsigned long hmm_flags,
+                              struct nouveau_drm *drm,
+                              struct nouveau_pfnmap_args *args, u32 size,
+                              unsigned long hmm_flags,
                               struct svm_notifier *notifier)
 {
        unsigned long timeout =
@@ -585,10 +604,10 @@ static int nouveau_range_fault(struct nouveau_svmm *svmm,
                break;
        }
 
-       nouveau_hmm_convert_pfn(drm, &range, ioctl_addr);
+       nouveau_hmm_convert_pfn(drm, &range, args);
 
        svmm->vmm->vmm.object.client->super = true;
-       ret = nvif_object_ioctl(&svmm->vmm->vmm.object, data, size, NULL);
+       ret = nvif_object_ioctl(&svmm->vmm->vmm.object, args, size, NULL);
        svmm->vmm->vmm.object.client->super = false;
        mutex_unlock(&svmm->mutex);
 
@@ -717,12 +736,13 @@ nouveau_svm_fault(struct nvif_notify *notify)
                                                   args.i.p.addr, args.i.p.size,
                                                   &nouveau_svm_mni_ops);
                if (!ret) {
-                       ret = nouveau_range_fault(svmm, svm->drm, &args,
-                               sizeof(args), args.phys, hmm_flags, &notifier);
+                       ret = nouveau_range_fault(svmm, svm->drm, &args.i,
+                               sizeof(args), hmm_flags, &notifier);
                        mmu_interval_notifier_remove(&notifier.notifier);
                }
                mmput(mm);
 
+               limit = args.i.p.addr + args.i.p.size;
                for (fn = fi; ++fn < buffer->fault_nr; ) {
                        /* It's okay to skip over duplicate addresses from the
                         * same SVMM as faults are ordered by access type such
@@ -730,9 +750,16 @@ nouveau_svm_fault(struct nvif_notify *notify)
                         *
                         * ie. WRITE faults appear first, thus any handling of
                         * pending READ faults will already be satisfied.
+                        * But if a large page is mapped, make sure subsequent
+                        * fault addresses have sufficient access permission.
                         */
                        if (buffer->fault[fn]->svmm != svmm ||
-                           buffer->fault[fn]->addr >= limit)
+                           buffer->fault[fn]->addr >= limit ||
+                           (buffer->fault[fi]->access == 0 /* READ. */ &&
+                            !(args.phys[0] & NVIF_VMM_PFNMAP_V0_V)) ||
+                           (buffer->fault[fi]->access != 0 /* READ. */ &&
+                            buffer->fault[fi]->access != 3 /* PREFETCH. */ &&
+                            !(args.phys[0] & NVIF_VMM_PFNMAP_V0_W)))
                                break;
                }