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drm/i915/gtt: Add read only pages to gen8_pte_encode

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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 <jon.bloomfield@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712185315.3288-1-chris@chris-wilson.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jon Bloomfield 2018-07-12 19:53:10 +01:00 • committed by Greg Kroah-Hartman
parent b575bf8be3
commit 6d0cfddc7a
1 changed files with 13 additions and 9 deletions
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22
drivers/gpu/drm/i915/i915_gem_gtt.c
View file

@ -172,11 +172,14 @@ static void ppgtt_unbind_vma(struct i915_vma *vma)
static gen8_pte_t gen8_pte_encode(dma_addr_t addr, static gen8_pte_t gen8_pte_encode(dma_addr_t addr,
enum i915_cache_level level, enum i915_cache_level level,
bool valid) bool valid, u32 flags)
{ {
gen8_pte_t pte = valid ? _PAGE_PRESENT | _PAGE_RW : 0; gen8_pte_t pte = valid ? _PAGE_PRESENT | _PAGE_RW : 0;
pte |= addr; pte |= addr;
if (unlikely(flags & PTE_READ_ONLY))
pte &= ~_PAGE_RW;
switch (level) { switch (level) {
case I915_CACHE_NONE: case I915_CACHE_NONE:
pte |= PPAT_UNCACHED_INDEX; pte |= PPAT_UNCACHED_INDEX;
@ -460,7 +463,7 @@ static void gen8_initialize_pt(struct i915_address_space *vm,
gen8_pte_t scratch_pte; gen8_pte_t scratch_pte;
scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page), scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page),
I915_CACHE_LLC, true); I915_CACHE_LLC, true, 0);
fill_px(vm->dev, pt, scratch_pte); fill_px(vm->dev, pt, scratch_pte);
} }
@ -757,8 +760,9 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
{ {
struct i915_hw_ppgtt *ppgtt = struct i915_hw_ppgtt *ppgtt =
container_of(vm, struct i915_hw_ppgtt, base); container_of(vm, struct i915_hw_ppgtt, base);
gen8_pte_t scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page), gen8_pte_t scratch_pte =
I915_CACHE_LLC, use_scratch); gen8_pte_encode(px_dma(vm->scratch_page),
I915_CACHE_LLC, use_scratch, 0);
if (!USES_FULL_48BIT_PPGTT(vm->dev)) { if (!USES_FULL_48BIT_PPGTT(vm->dev)) {
gen8_ppgtt_clear_pte_range(vm, &ppgtt->pdp, start, length, gen8_ppgtt_clear_pte_range(vm, &ppgtt->pdp, start, length,
@ -799,7 +803,7 @@ gen8_ppgtt_insert_pte_entries(struct i915_address_space *vm,
pt_vaddr[pte] = pt_vaddr[pte] =
gen8_pte_encode(sg_page_iter_dma_address(sg_iter), gen8_pte_encode(sg_page_iter_dma_address(sg_iter),
cache_level, true); cache_level, true, 0);
if (++pte == GEN8_PTES) { if (++pte == GEN8_PTES) {
kunmap_px(ppgtt, pt_vaddr); kunmap_px(ppgtt, pt_vaddr);
pt_vaddr = NULL; pt_vaddr = NULL;
@ -1447,7 +1451,7 @@ static void gen8_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
uint64_t start = ppgtt->base.start; uint64_t start = ppgtt->base.start;
uint64_t length = ppgtt->base.total; uint64_t length = ppgtt->base.total;
gen8_pte_t scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page), gen8_pte_t scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page),
I915_CACHE_LLC, true); I915_CACHE_LLC, true, 0);
if (!USES_FULL_48BIT_PPGTT(vm->dev)) { if (!USES_FULL_48BIT_PPGTT(vm->dev)) {
gen8_dump_pdp(&ppgtt->pdp, start, length, scratch_pte, m); gen8_dump_pdp(&ppgtt->pdp, start, length, scratch_pte, m);
@ -2357,7 +2361,7 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
addr = sg_dma_address(sg_iter.sg) + addr = sg_dma_address(sg_iter.sg) +
(sg_iter.sg_pgoffset << PAGE_SHIFT); (sg_iter.sg_pgoffset << PAGE_SHIFT);
gen8_set_pte(&gtt_entries[i], gen8_set_pte(&gtt_entries[i],
gen8_pte_encode(addr, level, true)); gen8_pte_encode(addr, level, true, 0));
i++; i++;
} }
@ -2370,7 +2374,7 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm,
*/ */
if (i != 0) if (i != 0)
WARN_ON(readq(&gtt_entries[i-1]) WARN_ON(readq(&gtt_entries[i-1])
!= gen8_pte_encode(addr, level, true)); != gen8_pte_encode(addr, level, true, 0));
/* This next bit makes the above posting read even more important. We /* This next bit makes the above posting read even more important. We
* want to flush the TLBs only after we're certain all the PTE updates * want to flush the TLBs only after we're certain all the PTE updates
@ -2444,7 +2448,7 @@ static void gen8_ggtt_clear_range(struct i915_address_space *vm,
scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page), scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page),
I915_CACHE_LLC, I915_CACHE_LLC,
use_scratch); use_scratch, 0);
for (i = 0; i < num_entries; i++) for (i = 0; i < num_entries; i++)
gen8_set_pte(&gtt_base[i], scratch_pte); gen8_set_pte(&gtt_base[i], scratch_pte);
readl(gtt_base); readl(gtt_base);