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drm/i915: Use batch length instead of object size in command parser

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Previously we couldn't trust the user-supplied batch length because
it came directly from userspace (i.e. untrusted code). It would have
affected what commands software parsed without regard to what hardware
would actually execute, leaving a potential hole.

With the parser now copying the user supplied batch buffer and writing
MI_NOP commands to any space after the copied region, we can safely use
the batch length input. This should be a performance win as the actual
batch length is frequently much smaller than the allocated object size.

v2: Fix handling of non-zero batch_start_offset

Issue: VIZ-4719
Signed-off-by: Brad Volkin <bradley.d.volkin@intel.com>
Reviewed-By: Jon Bloomfield <jon.bloomfield@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Brad Volkin 2014-12-11 12:13:10 -08:00 committed by Daniel Vetter
parent 78a423772d
commit b9ffd80ed6
3 changed files with 34 additions and 16 deletions
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48
drivers/gpu/drm/i915/i915_cmd_parser.c
View File

@ -850,11 +850,19 @@ finish:
/* Returns a vmap'd pointer to dest_obj, which the caller must unmap */
static u32 *copy_batch(struct drm_i915_gem_object *dest_obj,
struct drm_i915_gem_object *src_obj)
struct drm_i915_gem_object *src_obj,
u32 batch_start_offset,
u32 batch_len)
{
int ret = 0;
int needs_clflush = 0;
u32 *src_addr, *dest_addr = NULL;
u32 *src_base, *dest_base = NULL;
u32 *src_addr, *dest_addr;
u32 offset = batch_start_offset / sizeof(*dest_addr);
u32 end = batch_start_offset + batch_len;
if (end > dest_obj->base.size || end > src_obj->base.size)
return ERR_PTR(-E2BIG);
ret = i915_gem_obj_prepare_shmem_read(src_obj, &needs_clflush);
if (ret) {
@ -862,15 +870,17 @@ static u32 *copy_batch(struct drm_i915_gem_object *dest_obj,
return ERR_PTR(ret);
}
src_addr = vmap_batch(src_obj);
if (!src_addr) {
src_base = vmap_batch(src_obj);
if (!src_base) {
DRM_DEBUG_DRIVER("CMD: Failed to vmap batch\n");
ret = -ENOMEM;
goto unpin_src;
}
src_addr = src_base + offset;
if (needs_clflush)
drm_clflush_virt_range((char *)src_addr, src_obj->base.size);
drm_clflush_virt_range((char *)src_addr, batch_len);
ret = i915_gem_object_set_to_cpu_domain(dest_obj, true);
if (ret) {
@ -878,24 +888,27 @@ static u32 *copy_batch(struct drm_i915_gem_object *dest_obj,
goto unmap_src;
}
dest_addr = vmap_batch(dest_obj);
if (!dest_addr) {
dest_base = vmap_batch(dest_obj);
if (!dest_base) {
DRM_DEBUG_DRIVER("CMD: Failed to vmap shadow batch\n");
ret = -ENOMEM;
goto unmap_src;
}
memcpy(dest_addr, src_addr, src_obj->base.size);
if (dest_obj->base.size > src_obj->base.size)
memset((u8 *)dest_addr + src_obj->base.size, 0,
dest_obj->base.size - src_obj->base.size);
dest_addr = dest_base + offset;
if (batch_start_offset != 0)
memset((u8 *)dest_base, 0, batch_start_offset);
memcpy(dest_addr, src_addr, batch_len);
memset((u8 *)dest_addr + batch_len, 0, dest_obj->base.size - end);
unmap_src:
vunmap(src_addr);
vunmap(src_base);
unpin_src:
i915_gem_object_unpin_pages(src_obj);
return ret ? ERR_PTR(ret) : dest_addr;
return ret ? ERR_PTR(ret) : dest_base;
}
/**
@ -1016,6 +1029,7 @@ static bool check_cmd(const struct intel_engine_cs *ring,
* @batch_obj: the batch buffer in question
* @shadow_batch_obj: copy of the batch buffer in question
* @batch_start_offset: byte offset in the batch at which execution starts
* @batch_len: length of the commands in batch_obj
* @is_master: is the submitting process the drm master?
*
* Parses the specified batch buffer looking for privilege violations as
@ -1028,6 +1042,7 @@ int i915_parse_cmds(struct intel_engine_cs *ring,
struct drm_i915_gem_object *batch_obj,
struct drm_i915_gem_object *shadow_batch_obj,
u32 batch_start_offset,
u32 batch_len,
bool is_master)
{
int ret = 0;
@ -1035,7 +1050,8 @@ int i915_parse_cmds(struct intel_engine_cs *ring,
struct drm_i915_cmd_descriptor default_desc = { 0 };
bool oacontrol_set = false; /* OACONTROL tracking. See check_cmd() */
batch_base = copy_batch(shadow_batch_obj, batch_obj);
batch_base = copy_batch(shadow_batch_obj, batch_obj,
batch_start_offset, batch_len);
if (IS_ERR(batch_base)) {
DRM_DEBUG_DRIVER("CMD: Failed to copy batch\n");
return PTR_ERR(batch_base);
@ -1044,11 +1060,11 @@ int i915_parse_cmds(struct intel_engine_cs *ring,
cmd = batch_base + (batch_start_offset / sizeof(*cmd));
/*
* We use the source object's size because the shadow object is as
* We use the batch length as size because the shadow object is as
* large or larger and copy_batch() will write MI_NOPs to the extra
* space. Parsing should be faster in some cases this way.
*/
batch_end = cmd + (batch_obj->base.size / sizeof(*batch_end));
batch_end = cmd + (batch_len / sizeof(*batch_end));
while (cmd < batch_end) {
const struct drm_i915_cmd_descriptor *desc;

1
drivers/gpu/drm/i915/i915_drv.h
View File

@ -2965,6 +2965,7 @@ int i915_parse_cmds(struct intel_engine_cs *ring,
struct drm_i915_gem_object *batch_obj,
struct drm_i915_gem_object *shadow_batch_obj,
u32 batch_start_offset,
u32 batch_len,
bool is_master);
/* i915_suspend.c */

1
drivers/gpu/drm/i915/i915_gem_execbuffer.c
View File

@ -1421,6 +1421,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
batch_obj,
shadow_batch_obj,
args->batch_start_offset,
args->batch_len,
file->is_master);
i915_gem_object_ggtt_unpin(shadow_batch_obj);