diff options
Diffstat (limited to 'drivers/gpu/drm/i915/gem/i915_gem_shmem.c')
| -rw-r--r-- | drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 29 |
1 files changed, 13 insertions, 16 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c index 11f072193f3b..d77da59fae04 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c @@ -182,22 +182,7 @@ rebuild_st: if (i915_gem_object_needs_bit17_swizzle(obj)) i915_gem_object_do_bit_17_swizzle(obj, st); - /* - * EHL and JSL add the 'Bypass LLC' MOCS entry, which should make it - * possible for userspace to bypass the GTT caching bits set by the - * kernel, as per the given object cache_level. This is troublesome - * since the heavy flush we apply when first gathering the pages is - * skipped if the kernel thinks the object is coherent with the GPU. As - * a result it might be possible to bypass the cache and read the - * contents of the page directly, which could be stale data. If it's - * just a case of userspace shooting themselves in the foot then so be - * it, but since i915 takes the stance of always zeroing memory before - * handing it to userspace, we need to prevent this. - * - * By setting cache_dirty here we make the clflush in set_pages - * unconditional on such platforms. - */ - if (IS_JSL_EHL(i915) && obj->flags & I915_BO_ALLOC_USER) + if (i915_gem_object_can_bypass_llc(obj)) obj->cache_dirty = true; __i915_gem_object_set_pages(obj, st, sg_page_sizes); @@ -301,6 +286,8 @@ __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj, struct sg_table *pages, bool needs_clflush) { + struct drm_i915_private *i915 = to_i915(obj->base.dev); + GEM_BUG_ON(obj->mm.madv == __I915_MADV_PURGED); if (obj->mm.madv == I915_MADV_DONTNEED) @@ -312,6 +299,16 @@ __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj, drm_clflush_sg(pages); __start_cpu_write(obj); + /* + * On non-LLC platforms, force the flush-on-acquire if this is ever + * swapped-in. Our async flush path is not trust worthy enough yet(and + * happens in the wrong order), and with some tricks it's conceivable + * for userspace to change the cache-level to I915_CACHE_NONE after the + * pages are swapped-in, and since execbuf binds the object before doing + * the async flush, we have a race window. + */ + if (!HAS_LLC(i915)) + obj->cache_dirty = true; } void i915_gem_object_put_pages_shmem(struct drm_i915_gem_object *obj, struct sg_table *pages) |