From: Bob Beckett <robert.beckett@xxxxxxxxx>
Create a scratch page for the two unused PDPs and set all the PTEs
for them to point to it.
This patch addresses a page fault, and subsequent hang in pipe
control flush. In these cases, the Main Graphic Arbiter Error
register [0x40A0] showed a TLB Page Fault error, and a high memory
address (higher than the size of our PPGTT) was reported in the
Fault TLB RD Data0 register (0x4B10).
PDP2 & PDP3 were not set because, in theory, they aren't required
for our PPGTT size, but they should be mapped to a scratch page
anyway.
v2: Rebase on latest nightly.
Signed-off-by: Michel Thierry <michel.thierry@xxxxxxxxx> (v1)
Signed-off-by: Dave Gordon <david.s.gordon@xxxxxxxxx> (v2)
Signed-off-by: Oscar Mateo <oscar.mateo@xxxxxxxxx>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 79 +++++++++++++++++++++++++++++--------
drivers/gpu/drm/i915/i915_gem_gtt.h | 2 +
2 files changed, 65 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index b4b7cfd..7cb18e7 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -361,6 +361,11 @@ static void gen8_ppgtt_free(const struct i915_hw_ppgtt *ppgtt)
kfree(ppgtt->gen8_pt_dma_addr[i]);
}
+ /* Unused PDPs are always assigned to scratch page */
+ for (i = ppgtt->num_pd_pages; i < GEN8_LEGACY_PDPS; i++)
+ kfree(ppgtt->gen8_pt_dma_addr[i]);
+ __free_page(ppgtt->scratch_page);
+
__free_pages(ppgtt->pd_pages, get_order(ppgtt->num_pd_pages << PAGE_SHIFT));
}
@@ -385,6 +390,13 @@ static void gen8_ppgtt_unmap_pages(struct i915_hw_ppgtt *ppgtt)
PCI_DMA_BIDIRECTIONAL);
}
}
+
+ /* Unused PDPs are always assigned to scratch page */
+ for (i = ppgtt->num_pd_pages; i < GEN8_LEGACY_PDPS; i++) {
+ if (ppgtt->pd_dma_addr[i])
+ pci_unmap_page(hwdev, ppgtt->pd_dma_addr[i],
+ PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
+ }
}
static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
@@ -471,10 +483,21 @@ static int gen8_ppgtt_allocate_dma(struct i915_hw_ppgtt *ppgtt)
static int gen8_ppgtt_allocate_page_directories(struct i915_hw_ppgtt *ppgtt,
const int max_pdp)
{
- ppgtt->pd_pages = alloc_pages(GFP_KERNEL, get_order(max_pdp << PAGE_SHIFT));
- if (!ppgtt->pd_pages)
+ /* Scratch page for unmapped PDP's */
+ ppgtt->scratch_page = alloc_page(GFP_KERNEL);
+ if (!ppgtt->scratch_page)
return -ENOMEM;
+ /* Must allocate space for all 4 PDPs. HW has implemented cache which
+ * pre-fetches entries; that pre-fetch can attempt access for entries
+ * even if no resources are located in that range.
+ */
+ ppgtt->pd_pages = alloc_pages(GFP_KERNEL, GEN8_LEGACY_PDPS);
+ if (!ppgtt->pd_pages) {
+ __free_page(ppgtt->scratch_page);
+ return -ENOMEM;
+ }
+
ppgtt->num_pd_pages = 1 << get_order(max_pdp << PAGE_SHIFT);
BUG_ON(ppgtt->num_pd_pages > GEN8_LEGACY_PDPS);
@@ -492,6 +515,7 @@ static int gen8_ppgtt_alloc(struct i915_hw_ppgtt *ppgtt,
ret = gen8_ppgtt_allocate_page_tables(ppgtt, max_pdp);
if (ret) {
+ __free_page(ppgtt->scratch_page);
__free_pages(ppgtt->pd_pages, get_order(max_pdp << PAGE_SHIFT));
return ret;
}
@@ -526,18 +550,25 @@ static int gen8_ppgtt_setup_page_directories(struct i915_hw_ppgtt *ppgtt,
static int gen8_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt,
const int pd,
- const int pt)
+ const int pt,
+ const int max_pdp)
{
dma_addr_t pt_addr;
struct page *p;
int ret;
- p = ppgtt->gen8_pt_pages[pd][pt];
- 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);
- if (ret)
- return ret;
+ /* Unused PDPs need to have their ptes pointing to the
+ * existing scratch page.
+ */
+ if (pd < max_pdp) {
+ p = ppgtt->gen8_pt_pages[pd][pt];
+ 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);
+ if (ret)
+ return ret;
+ } else
+ pt_addr = ppgtt->scratch_dma_addr;
ppgtt->gen8_pt_dma_addr[pd][pt] = pt_addr;
@@ -559,6 +590,7 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
const int max_pdp = DIV_ROUND_UP(size, 1 << 30);
const int min_pt_pages = GEN8_PDES_PER_PAGE * max_pdp;
int i, j, ret;
+ gen8_gtt_pte_t *pt_vaddr, scratch_pte;
if (size % (1<<30))
DRM_INFO("Pages will be wasted unless GTT size (%llu) is divisible by 1GB\n", size);
@@ -568,30 +600,38 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
if (ret)
return ret;
- /*
- * 2. Create DMA mappings for the page directories and page tables.
- */
- for (i = 0; i < max_pdp; i++) {
+ /* 2. Map the scratch page */
+ ppgtt->scratch_dma_addr =
+ pci_map_page(ppgtt->base.dev->pdev,
+ ppgtt->scratch_page, 0, PAGE_SIZE,
+ PCI_DMA_BIDIRECTIONAL);
+
+ ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, ppgtt->scratch_dma_addr);
+ if (ret)
+ goto bail;
+
+ /* 3. Create DMA mappings for the page directories and page tables. */
+ for (i = 0; i < GEN8_LEGACY_PDPS; i++) {
ret = gen8_ppgtt_setup_page_directories(ppgtt, i);
if (ret)
goto bail;
for (j = 0; j < GEN8_PDES_PER_PAGE; j++) {
- ret = gen8_ppgtt_setup_page_tables(ppgtt, i, j);
+ ret = gen8_ppgtt_setup_page_tables(ppgtt, i, j, max_pdp);
if (ret)
goto bail;
}
}
/*
- * 3. Map all the page directory entires to point to the page tables
+ * 4. Map all the page directory entries to point to the page tables
* we've allocated.
*
* For now, the PPGTT helper functions all require that the PDEs are
* plugged in correctly. So we do that now/here. For aliasing PPGTT, we
* will never need to touch the PDEs again.
*/
- for (i = 0; i < max_pdp; i++) {
+ for (i = 0; i < GEN8_LEGACY_PDPS; i++) {
gen8_ppgtt_pde_t *pd_vaddr;
pd_vaddr = kmap_atomic(&ppgtt->pd_pages[i]);
for (j = 0; j < GEN8_PDES_PER_PAGE; j++) {
@@ -614,6 +654,13 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
ppgtt->base.clear_range(&ppgtt->base, 0, ppgtt->base.total, true);
+ scratch_pte = gen8_pte_encode(ppgtt->base.scratch.addr,
+ I915_CACHE_LLC, true);
+ pt_vaddr = kmap_atomic(ppgtt->scratch_page);
+ for (i = 0; i < GEN8_PTES_PER_PAGE; i++)
+ pt_vaddr[i] = scratch_pte;
+ kunmap_atomic(pt_vaddr);
+
DRM_DEBUG_DRIVER("Allocated %d pages for page directories (%d wasted)\n",
ppgtt->num_pd_pages, ppgtt->num_pd_pages - max_pdp);
DRM_DEBUG_DRIVER("Allocated %d pages for page tables (%lld wasted)\n",
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index 666c938..02032b3 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -249,6 +249,7 @@ struct i915_hw_ppgtt {
struct page **gen8_pt_pages[GEN8_LEGACY_PDPS];
};
struct page *pd_pages;
+ struct page *scratch_page;
union {
uint32_t pd_offset;
dma_addr_t pd_dma_addr[GEN8_LEGACY_PDPS];
@@ -258,6 +259,7 @@ struct i915_hw_ppgtt {
dma_addr_t *gen8_pt_dma_addr[4];
};
+ dma_addr_t scratch_dma_addr;
struct intel_context *ctx;
int (*enable)(struct i915_hw_ppgtt *ppgtt);
--
1.9.3
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