From bebb6a49fd662b312448c152ccf162e9f283e221 Mon Sep 17 00:00:00 2001 From: Jon Bloomfield Date: Thu, 12 Jul 2018 19:53:10 +0100 Subject: [PATCH] drm/i915/gtt: Add read only pages to gen8_pte_encode commit 25dda4dabeeb12af5209b0183c788ef2a88dabbe upstream. We can set a bit inside the ppGTT PTE to indicate a page is read-only; writes from the GPU will be discarded. We can use this to protect pages and in particular support read-only userptr mappings (necessary for importing PROT_READ vma). Signed-off-by: Jon Bloomfield Signed-off-by: Chris Wilson Cc: Joonas Lahtinen Cc: Matthew Auld Reviewed-by: Joonas Lahtinen Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20180712185315.3288-1-chris@chris-wilson.co.uk Reviewed-by: Jon Bloomfield Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/i915_gem_gtt.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index 0bb4232f66bc..088f9c03cbb4 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -197,11 +197,14 @@ static void ppgtt_unbind_vma(struct i915_vma *vma) static gen8_pte_t gen8_pte_encode(dma_addr_t addr, enum i915_cache_level level, - bool valid) + bool valid, u32 flags) { gen8_pte_t pte = valid ? _PAGE_PRESENT | _PAGE_RW : 0; pte |= addr; + if (unlikely(flags & PTE_READ_ONLY)) + pte &= ~_PAGE_RW; + switch (level) { case I915_CACHE_NONE: pte |= PPAT_UNCACHED_INDEX; @@ -472,7 +475,7 @@ static void gen8_initialize_pt(struct i915_address_space *vm, gen8_pte_t scratch_pte; scratch_pte = gen8_pte_encode(vm->scratch_page.daddr, - I915_CACHE_LLC, true); + I915_CACHE_LLC, true, 0); fill_px(vm->dev, pt, scratch_pte); } @@ -769,7 +772,7 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm, { struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm); gen8_pte_t scratch_pte = gen8_pte_encode(vm->scratch_page.daddr, - I915_CACHE_LLC, use_scratch); + I915_CACHE_LLC, use_scratch, 0); if (!USES_FULL_48BIT_PPGTT(vm->dev)) { gen8_ppgtt_clear_pte_range(vm, &ppgtt->pdp, start, length, @@ -809,7 +812,7 @@ 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); + cache_level, true, 0); if (++pte == GEN8_PTES) { kunmap_px(ppgtt, pt_vaddr); pt_vaddr = NULL; @@ -1452,7 +1455,7 @@ static void gen8_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m) uint64_t start = ppgtt->base.start; uint64_t length = ppgtt->base.total; gen8_pte_t scratch_pte = gen8_pte_encode(vm->scratch_page.daddr, - I915_CACHE_LLC, true); + I915_CACHE_LLC, true, 0); if (!USES_FULL_48BIT_PPGTT(vm->dev)) { gen8_dump_pdp(&ppgtt->pdp, start, length, scratch_pte, m); @@ -2321,7 +2324,7 @@ static void gen8_ggtt_insert_page(struct i915_address_space *vm, rpm_atomic_seq = assert_rpm_atomic_begin(dev_priv); - gen8_set_pte(pte, gen8_pte_encode(addr, level, true)); + gen8_set_pte(pte, gen8_pte_encode(addr, level, true, 0)); I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN); POSTING_READ(GFX_FLSH_CNTL_GEN6); @@ -2348,7 +2351,7 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm, gtt_entries = (gen8_pte_t __iomem *)ggtt->gsm + (start >> PAGE_SHIFT); for_each_sgt_dma(addr, sgt_iter, st) { - gtt_entry = gen8_pte_encode(addr, level, true); + gtt_entry = gen8_pte_encode(addr, level, true, 0); gen8_set_pte(>t_entries[i++], gtt_entry); } @@ -2499,7 +2502,7 @@ static void gen8_ggtt_clear_range(struct i915_address_space *vm, scratch_pte = gen8_pte_encode(vm->scratch_page.daddr, I915_CACHE_LLC, - use_scratch); + use_scratch, 0); for (i = 0; i < num_entries; i++) gen8_set_pte(>t_base[i], scratch_pte); readl(gtt_base); -- 2.43.0