drm/i915: Create a dummy object for gen6 ppgtt
authorMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Wed, 17 Nov 2021 14:20:20 +0000 (14:20 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 8 Dec 2022 10:28:37 +0000 (11:28 +0100)
[ Upstream commit b0b0f2d225da6fe58417fae37e3f797e2db27b62 ]

We currently have to special case vma->obj being NULL because
of gen6 ppgtt and mock_engine. Fix gen6 ppgtt, so we may soon
be able to remove a few checks. As the object only exists as
a fake object pointing to ggtt, we have no backing storage,
so no real object is created. It just has to look real enough.

Also kill pin_mutex, it's not compatible with ww locking,
and we can use the vm lock instead.

v2:
  - Drop IS_SHRINKABLE and shorten overly long line
v3:
  - Checkpatch fix for alignment

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117142024.1043017-2-matthew.auld@intel.com
Stable-dep-of: 20e377e7b2e7 ("drm/i915/gt: Use i915_vm_put on ppgtt_create error paths")
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/gpu/drm/i915/gem/i915_gem_internal.c
drivers/gpu/drm/i915/gt/gen6_ppgtt.c
drivers/gpu/drm/i915/gt/gen6_ppgtt.h
drivers/gpu/drm/i915/i915_drv.h

index e5ae9c0..3c8de65 100644 (file)
@@ -143,24 +143,10 @@ static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
        .put_pages = i915_gem_object_put_pages_internal,
 };
 
-/**
- * i915_gem_object_create_internal: create an object with volatile pages
- * @i915: the i915 device
- * @size: the size in bytes of backing storage to allocate for the object
- *
- * Creates a new object that wraps some internal memory for private use.
- * This object is not backed by swappable storage, and as such its contents
- * are volatile and only valid whilst pinned. If the object is reaped by the
- * shrinker, its pages and data will be discarded. Equally, it is not a full
- * GEM object and so not valid for access from userspace. This makes it useful
- * for hardware interfaces like ringbuffers (which are pinned from the time
- * the request is written to the time the hardware stops accessing it), but
- * not for contexts (which need to be preserved when not active for later
- * reuse). Note that it is not cleared upon allocation.
- */
 struct drm_i915_gem_object *
-i915_gem_object_create_internal(struct drm_i915_private *i915,
-                               phys_addr_t size)
+__i915_gem_object_create_internal(struct drm_i915_private *i915,
+                                 const struct drm_i915_gem_object_ops *ops,
+                                 phys_addr_t size)
 {
        static struct lock_class_key lock_class;
        struct drm_i915_gem_object *obj;
@@ -177,7 +163,7 @@ i915_gem_object_create_internal(struct drm_i915_private *i915,
                return ERR_PTR(-ENOMEM);
 
        drm_gem_private_object_init(&i915->drm, &obj->base, size);
-       i915_gem_object_init(obj, &i915_gem_object_internal_ops, &lock_class, 0);
+       i915_gem_object_init(obj, ops, &lock_class, 0);
        obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE;
 
        /*
@@ -197,3 +183,25 @@ i915_gem_object_create_internal(struct drm_i915_private *i915,
 
        return obj;
 }
+
+/**
+ * i915_gem_object_create_internal: create an object with volatile pages
+ * @i915: the i915 device
+ * @size: the size in bytes of backing storage to allocate for the object
+ *
+ * Creates a new object that wraps some internal memory for private use.
+ * This object is not backed by swappable storage, and as such its contents
+ * are volatile and only valid whilst pinned. If the object is reaped by the
+ * shrinker, its pages and data will be discarded. Equally, it is not a full
+ * GEM object and so not valid for access from userspace. This makes it useful
+ * for hardware interfaces like ringbuffers (which are pinned from the time
+ * the request is written to the time the hardware stops accessing it), but
+ * not for contexts (which need to be preserved when not active for later
+ * reuse). Note that it is not cleared upon allocation.
+ */
+struct drm_i915_gem_object *
+i915_gem_object_create_internal(struct drm_i915_private *i915,
+                               phys_addr_t size)
+{
+       return __i915_gem_object_create_internal(i915, &i915_gem_object_internal_ops, size);
+}
index 1aee5e6..557ef25 100644 (file)
@@ -262,13 +262,10 @@ static void gen6_ppgtt_cleanup(struct i915_address_space *vm)
 {
        struct gen6_ppgtt *ppgtt = to_gen6_ppgtt(i915_vm_to_ppgtt(vm));
 
-       __i915_vma_put(ppgtt->vma);
-
        gen6_ppgtt_free_pd(ppgtt);
        free_scratch(vm);
 
        mutex_destroy(&ppgtt->flush);
-       mutex_destroy(&ppgtt->pin_mutex);
 
        free_pd(&ppgtt->base.vm, ppgtt->base.pd);
 }
@@ -331,37 +328,6 @@ static const struct i915_vma_ops pd_vma_ops = {
        .unbind_vma = pd_vma_unbind,
 };
 
-static struct i915_vma *pd_vma_create(struct gen6_ppgtt *ppgtt, int size)
-{
-       struct i915_ggtt *ggtt = ppgtt->base.vm.gt->ggtt;
-       struct i915_vma *vma;
-
-       GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_PAGE_SIZE));
-       GEM_BUG_ON(size > ggtt->vm.total);
-
-       vma = i915_vma_alloc();
-       if (!vma)
-               return ERR_PTR(-ENOMEM);
-
-       i915_active_init(&vma->active, NULL, NULL, 0);
-
-       kref_init(&vma->ref);
-       mutex_init(&vma->pages_mutex);
-       vma->vm = i915_vm_get(&ggtt->vm);
-       vma->ops = &pd_vma_ops;
-       vma->private = ppgtt;
-
-       vma->size = size;
-       vma->fence_size = size;
-       atomic_set(&vma->flags, I915_VMA_GGTT);
-       vma->ggtt_view.type = I915_GGTT_VIEW_ROTATED; /* prevent fencing */
-
-       INIT_LIST_HEAD(&vma->obj_link);
-       INIT_LIST_HEAD(&vma->closed_link);
-
-       return vma;
-}
-
 int gen6_ppgtt_pin(struct i915_ppgtt *base, struct i915_gem_ww_ctx *ww)
 {
        struct gen6_ppgtt *ppgtt = to_gen6_ppgtt(base);
@@ -378,24 +344,85 @@ int gen6_ppgtt_pin(struct i915_ppgtt *base, struct i915_gem_ww_ctx *ww)
        if (atomic_add_unless(&ppgtt->pin_count, 1, 0))
                return 0;
 
-       if (mutex_lock_interruptible(&ppgtt->pin_mutex))
-               return -EINTR;
+       /* grab the ppgtt resv to pin the object */
+       err = i915_vm_lock_objects(&ppgtt->base.vm, ww);
+       if (err)
+               return err;
 
        /*
         * PPGTT PDEs reside in the GGTT and consists of 512 entries. The
         * allocator works in address space sizes, so it's multiplied by page
         * size. We allocate at the top of the GTT to avoid fragmentation.
         */
-       err = 0;
-       if (!atomic_read(&ppgtt->pin_count))
+       if (!atomic_read(&ppgtt->pin_count)) {
                err = i915_ggtt_pin(ppgtt->vma, ww, GEN6_PD_ALIGN, PIN_HIGH);
+
+               GEM_BUG_ON(ppgtt->vma->fence);
+               clear_bit(I915_VMA_CAN_FENCE_BIT, __i915_vma_flags(ppgtt->vma));
+       }
        if (!err)
                atomic_inc(&ppgtt->pin_count);
-       mutex_unlock(&ppgtt->pin_mutex);
 
        return err;
 }
 
+static int pd_dummy_obj_get_pages(struct drm_i915_gem_object *obj)
+{
+       obj->mm.pages = ZERO_SIZE_PTR;
+       return 0;
+}
+
+static void pd_dummy_obj_put_pages(struct drm_i915_gem_object *obj,
+                                  struct sg_table *pages)
+{
+}
+
+static const struct drm_i915_gem_object_ops pd_dummy_obj_ops = {
+       .name = "pd_dummy_obj",
+       .get_pages = pd_dummy_obj_get_pages,
+       .put_pages = pd_dummy_obj_put_pages,
+};
+
+static struct i915_page_directory *
+gen6_alloc_top_pd(struct gen6_ppgtt *ppgtt)
+{
+       struct i915_ggtt * const ggtt = ppgtt->base.vm.gt->ggtt;
+       struct i915_page_directory *pd;
+       int err;
+
+       pd = __alloc_pd(I915_PDES);
+       if (unlikely(!pd))
+               return ERR_PTR(-ENOMEM);
+
+       pd->pt.base = __i915_gem_object_create_internal(ppgtt->base.vm.gt->i915,
+                                                       &pd_dummy_obj_ops,
+                                                       I915_PDES * SZ_4K);
+       if (IS_ERR(pd->pt.base)) {
+               err = PTR_ERR(pd->pt.base);
+               pd->pt.base = NULL;
+               goto err_pd;
+       }
+
+       pd->pt.base->base.resv = i915_vm_resv_get(&ppgtt->base.vm);
+       pd->pt.base->shares_resv_from = &ppgtt->base.vm;
+
+       ppgtt->vma = i915_vma_instance(pd->pt.base, &ggtt->vm, NULL);
+       if (IS_ERR(ppgtt->vma)) {
+               err = PTR_ERR(ppgtt->vma);
+               ppgtt->vma = NULL;
+               goto err_pd;
+       }
+
+       /* The dummy object we create is special, override ops.. */
+       ppgtt->vma->ops = &pd_vma_ops;
+       ppgtt->vma->private = ppgtt;
+       return pd;
+
+err_pd:
+       free_pd(&ppgtt->base.vm, pd);
+       return ERR_PTR(err);
+}
+
 void gen6_ppgtt_unpin(struct i915_ppgtt *base)
 {
        struct gen6_ppgtt *ppgtt = to_gen6_ppgtt(base);
@@ -427,7 +454,6 @@ struct i915_ppgtt *gen6_ppgtt_create(struct intel_gt *gt)
                return ERR_PTR(-ENOMEM);
 
        mutex_init(&ppgtt->flush);
-       mutex_init(&ppgtt->pin_mutex);
 
        ppgtt_init(&ppgtt->base, gt);
        ppgtt->base.vm.pd_shift = ilog2(SZ_4K * SZ_4K / sizeof(gen6_pte_t));
@@ -442,19 +468,13 @@ struct i915_ppgtt *gen6_ppgtt_create(struct intel_gt *gt)
        ppgtt->base.vm.alloc_pt_dma = alloc_pt_dma;
        ppgtt->base.vm.pte_encode = ggtt->vm.pte_encode;
 
-       ppgtt->base.pd = __alloc_pd(I915_PDES);
-       if (!ppgtt->base.pd) {
-               err = -ENOMEM;
-               goto err_free;
-       }
-
        err = gen6_ppgtt_init_scratch(ppgtt);
        if (err)
-               goto err_pd;
+               goto err_free;
 
-       ppgtt->vma = pd_vma_create(ppgtt, GEN6_PD_SIZE);
-       if (IS_ERR(ppgtt->vma)) {
-               err = PTR_ERR(ppgtt->vma);
+       ppgtt->base.pd = gen6_alloc_top_pd(ppgtt);
+       if (IS_ERR(ppgtt->base.pd)) {
+               err = PTR_ERR(ppgtt->base.pd);
                goto err_scratch;
        }
 
@@ -462,10 +482,7 @@ struct i915_ppgtt *gen6_ppgtt_create(struct intel_gt *gt)
 
 err_scratch:
        free_scratch(&ppgtt->base.vm);
-err_pd:
-       free_pd(&ppgtt->base.vm, ppgtt->base.pd);
 err_free:
-       mutex_destroy(&ppgtt->pin_mutex);
        kfree(ppgtt);
        return ERR_PTR(err);
 }
index 6a61a5c..9b498ca 100644 (file)
@@ -19,7 +19,6 @@ struct gen6_ppgtt {
        u32 pp_dir;
 
        atomic_t pin_count;
-       struct mutex pin_mutex;
 
        bool scan_for_unused_pt;
 };
index 005b1ce..236cfee 100644 (file)
@@ -1905,6 +1905,10 @@ int i915_gem_evict_vm(struct i915_address_space *vm);
 struct drm_i915_gem_object *
 i915_gem_object_create_internal(struct drm_i915_private *dev_priv,
                                phys_addr_t size);
+struct drm_i915_gem_object *
+__i915_gem_object_create_internal(struct drm_i915_private *dev_priv,
+                                 const struct drm_i915_gem_object_ops *ops,
+                                 phys_addr_t size);
 
 /* i915_gem_tiling.c */
 static inline bool i915_gem_object_needs_bit17_swizzle(struct drm_i915_gem_object *obj)