Similar to gen6, while setting up a page table, make all entries of the
pt point to the scratch page before mapping; this is to be safe in case
of out of bound access or proactive prefetch.
Systems without LLC require an explicit flush.
v2: Expanded commit text and fixed indentation (Mika)
Signed-off-by: Michel Thierry <michel.thierry@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 8e47caf..cd28e343 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -332,6 +332,24 @@ static void unmap_and_free_pt(struct i915_page_table *pt,
kfree(pt);
}
+static void gen8_initialize_pt(struct i915_address_space *vm,
+ struct i915_page_table *pt)
+{
+ gen8_pte_t *pt_vaddr, scratch_pte;
+ int i;
+
+ pt_vaddr = kmap_atomic(pt->page);
+ scratch_pte = gen8_pte_encode(vm->scratch.addr,
+ I915_CACHE_LLC, true);
+
+ for (i = 0; i < GEN8_PTES; i++)
+ pt_vaddr[i] = scratch_pte;
+
+ if (!HAS_LLC(vm->dev))
+ drm_clflush_virt_range(pt_vaddr, PAGE_SIZE);
+ kunmap_atomic(pt_vaddr);
+}
+
static struct i915_page_table *alloc_pt_single(struct drm_device *dev)
{
struct i915_page_table *pt;
@@ -429,7 +447,7 @@ static struct i915_page_directory *alloc_pd_single(void)
if (!pd)
return ERR_PTR(-ENOMEM);
- pd->page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ pd->page = alloc_page(GFP_KERNEL);
if (!pd->page) {
kfree(pd);
return ERR_PTR(-ENOMEM);
@@ -719,6 +737,8 @@ static int gen8_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt,
struct page *p = ptab->page;
int ret;
+ gen8_initialize_pt(&ppgtt->base, ptab);
+
pt_addr = pci_map_page(ppgtt->base.dev->pdev,
p, 0, PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, pt_addr);
--
2.1.1
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