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Commit 85e04705 authored by Jon Bloomfield's avatar Jon Bloomfield Committed by Greg Kroah-Hartman
Browse files

drm/i915/gtt: Read-only pages for insert_entries on bdw+ 



commit 250f8c8140ac0a5e5acb91891d6813f12778b224 upstream.

Hook up the flags to allow read-only ppGTT mappings for gen8+

v2: Include a selftest to check that writes to a readonly PTE are
dropped
v3: Don't duplicate cpu_check() as we can just reuse it, and even worse
don't wholesale copy the theory-of-operation comment from igt_ctx_exec
without changing it to explain the intention behind the new test!
v4: Joonas really likes magic mystery values

Signed-off-by: default avatarJon Bloomfield <jon.bloomfield@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712185315.3288-2-chris@chris-wilson.co.uk


Signed-off-by: default avatarJon Bloomfield <jon.bloomfield@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bebb6a49

drivers/gpu/drm/i915/i915_gem_gtt.c

+20 −8
Original line number Diff line number Diff line
@@ -177,7 +177,7 @@ static int ppgtt_bind_vma(struct i915_vma *vma, 


	vma->pages = vma->obj->pages;



	/* Currently applicable only to VLV */

	/* Applicable to VLV, and gen8+ */

	if (vma->obj->gt_ro)

		pte_flags |= PTE_READ_ONLY;
@@ -793,7 +793,8 @@ gen8_ppgtt_insert_pte_entries(struct i915_address_space *vm, 
			      struct i915_page_directory_pointer *pdp,

			      struct sg_page_iter *sg_iter,

			      uint64_t start,

			      enum i915_cache_level cache_level)

			      enum i915_cache_level cache_level,

			      u32 flags)

{

	struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);

	gen8_pte_t *pt_vaddr;
@@ -812,7 +813,7 @@ gen8_ppgtt_insert_pte_entries(struct i915_address_space *vm, 


		pt_vaddr[pte] =

			gen8_pte_encode(sg_page_iter_dma_address(sg_iter),

					cache_level, true, 0);

					cache_level, true, flags);

		if (++pte == GEN8_PTES) {

			kunmap_px(ppgtt, pt_vaddr);

			pt_vaddr = NULL;
@@ -833,7 +834,7 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm, 
				      struct sg_table *pages,

				      uint64_t start,

				      enum i915_cache_level cache_level,

				      u32 unused)

				      u32 flags)

{

	struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);

	struct sg_page_iter sg_iter;
@@ -842,7 +843,7 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm, 


	if (!USES_FULL_48BIT_PPGTT(vm->dev)) {

		gen8_ppgtt_insert_pte_entries(vm, &ppgtt->pdp, &sg_iter, start,

					      cache_level);

					      cache_level, flags);

	} else {

		struct i915_page_directory_pointer *pdp;

		uint64_t pml4e;
@@ -850,7 +851,7 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm, 


		gen8_for_each_pml4e(pdp, &ppgtt->pml4, start, length, pml4e) {

			gen8_ppgtt_insert_pte_entries(vm, pdp, &sg_iter,

						      start, cache_level);

						      start, cache_level, flags);

		}

	}

}
@@ -1523,6 +1524,10 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt) 
	ppgtt->base.clear_range = gen8_ppgtt_clear_range;

	ppgtt->base.unbind_vma = ppgtt_unbind_vma;

	ppgtt->base.bind_vma = ppgtt_bind_vma;



	/* From bdw, there is support for read-only pages in the PPGTT */

	ppgtt->base.has_read_only = true;



	ppgtt->debug_dump = gen8_dump_ppgtt;



	if (USES_FULL_48BIT_PPGTT(ppgtt->base.dev)) {
@@ -2335,7 +2340,7 @@ static void gen8_ggtt_insert_page(struct i915_address_space *vm, 
static void gen8_ggtt_insert_entries(struct i915_address_space *vm,

				     struct sg_table *st,

				     uint64_t start,

				     enum i915_cache_level level, u32 unused)

				     enum i915_cache_level level, u32 flags)

{

	struct drm_i915_private *dev_priv = to_i915(vm->dev);

	struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm);
@@ -2346,6 +2351,9 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm, 
	int rpm_atomic_seq;

	int i = 0;



	/* The GTT does not support read-only mappings */

	GEM_BUG_ON(flags & PTE_READ_ONLY);



	rpm_atomic_seq = assert_rpm_atomic_begin(dev_priv);



	gtt_entries = (gen8_pte_t __iomem *)ggtt->gsm + (start >> PAGE_SHIFT);
@@ -2607,7 +2615,7 @@ static int ggtt_bind_vma(struct i915_vma *vma, 
	if (ret)

		return ret;



	/* Currently applicable only to VLV */

	/* Applicable to VLV (gen8+ do not support RO in the GGTT) */

	if (obj->gt_ro)

		pte_flags |= PTE_READ_ONLY;
@@ -3196,6 +3204,10 @@ int i915_ggtt_init_hw(struct drm_i915_private *dev_priv) 
	ggtt->base.total -= PAGE_SIZE;

	i915_address_space_init(&ggtt->base, dev_priv);

	ggtt->base.total += PAGE_SIZE;



	/* Only VLV supports read-only GGTT mappings */

	ggtt->base.has_read_only = IS_VALLEYVIEW(dev_priv);



	if (!HAS_LLC(dev_priv))

		ggtt->base.mm.color_adjust = i915_gtt_color_adjust;

drivers/gpu/drm/i915/i915_gem_gtt.h

+3 −0
Original line number Diff line number Diff line
@@ -392,6 +392,9 @@ struct i915_address_space { 
	 */

	struct list_head unbound_list;



	/* Some systems support read-only mappings for GGTT and/or PPGTT */

	bool has_read_only:1;



	/* FIXME: Need a more generic return type */

	gen6_pte_t (*pte_encode)(dma_addr_t addr,

				 enum i915_cache_level level,

drivers/gpu/drm/i915/intel_ringbuffer.c

+8 −3
Original line number Diff line number Diff line
@@ -1951,6 +1951,7 @@ void intel_ring_unpin(struct intel_ring *ring) 
static struct i915_vma *

intel_ring_create_vma(struct drm_i915_private *dev_priv, int size)

{

	struct i915_address_space *vm = &dev_priv->ggtt.base;

	struct drm_i915_gem_object *obj;

	struct i915_vma *vma;
@@ -1960,10 +1961,14 @@ intel_ring_create_vma(struct drm_i915_private *dev_priv, int size) 
	if (IS_ERR(obj))

		return ERR_CAST(obj);



	/* mark ring buffers as read-only from GPU side by default */

	/*

	 * Mark ring buffers as read-only from GPU side (so no stray overwrites)

	 * if supported by the platform's GGTT.

	 */

	if (vm->has_read_only)

		obj->gt_ro = 1;



	vma = i915_vma_create(obj, &dev_priv->ggtt.base, NULL);

	vma = i915_vma_create(obj, vm, NULL);

	if (IS_ERR(vma))

		goto err;