Wipe VRAM memory containing sensitive data when moving or releasing
BOs. Clearing the memory is pipelined to minimize any impact on
subsequent memory allocation latency. Use of a poison value should
help debug future use-after-free bugs.
When moving BOs, the existing ttm_bo_pipelined_move ensures that the
memory won't be reused before being wiped.
When releasing BOs, the BO is fenced with the memory fill operation,
which results in queuing the BO for a delayed delete.
Signed-off-by: Felix Kuehling <felix.kuehl...@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 33 ++++++++++++++++++++++
drivers/gpu/drm/amd/amdgpu/amdgpu_object.h | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 17 +++++++++++
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 2 ++
4 files changed, 53 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 989b7b55cb2e..06494cbc2349 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -1211,6 +1211,39 @@ void amdgpu_bo_move_notify(struct ttm_buffer_object *bo,
trace_amdgpu_bo_move(abo, new_mem->mem_type, old_mem->mem_type);
}
+/**
+ * amdgpu_bo_move_notify - notification about a BO being released
+ * @bo: pointer to a buffer object
+ *
+ * Wipes VRAM buffers whose contents should not be leaked before the
+ * memory is released.
+ */
+void amdgpu_bo_release_notify(struct ttm_buffer_object *bo)
+{
+ struct dma_fence *fence = NULL;
+ struct amdgpu_bo *abo;
+ int r;
+
+ if (!amdgpu_bo_is_amdgpu_bo(bo))
+ return;
+
+ abo = ttm_to_amdgpu_bo(bo);
+
+ if (bo->mem.mem_type != TTM_PL_VRAM || !bo->mem.mm_node ||
+ !(abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE))
+ return;
+
+ reservation_object_lock(bo->resv, NULL);
+
+ r = amdgpu_fill_buffer(abo, AMDGPU_POISON, bo->resv, &fence);
+ if (!WARN_ON(r)) {
+ amdgpu_bo_fence(abo, fence, false);
+ dma_fence_put(fence);
+ }
+
+ reservation_object_unlock(bo->resv);
+}
+
/**
* amdgpu_bo_fault_reserve_notify - notification about a memory fault
* @bo: pointer to a buffer object
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
index d60593cc436e..e302384fe003 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
@@ -265,6 +265,7 @@ int amdgpu_bo_get_metadata(struct amdgpu_bo *bo, void
*buffer,
void amdgpu_bo_move_notify(struct ttm_buffer_object *bo,
bool evict,
struct ttm_mem_reg *new_mem);
+void amdgpu_bo_release_notify(struct ttm_buffer_object *bo);
int amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo);
void amdgpu_bo_fence(struct amdgpu_bo *bo, struct dma_fence *fence,
bool shared);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 5d85617886b3..ae0eb64e734b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -437,6 +437,22 @@ static int amdgpu_move_blit(struct ttm_buffer_object *bo,
if (r)
goto error;
+ /* clear the space being freed */
+ if (old_mem->mem_type == TTM_PL_VRAM &&
+ (ttm_to_amdgpu_bo(bo)->flags &
+ AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE)) {
+ struct dma_fence *wipe_fence = NULL;
+
+ r = amdgpu_fill_buffer(ttm_to_amdgpu_bo(bo), AMDGPU_POISON,
+ NULL, &wipe_fence);
+ if (r) {
+ goto error;
+ } else if (wipe_fence) {
+ dma_fence_put(fence);
+ fence = wipe_fence;
+ }
+ }
+
/* Always block for VM page tables before committing the new location */
if (bo->type == ttm_bo_type_kernel)
r = ttm_bo_move_accel_cleanup(bo, fence, true, new_mem);
@@ -1558,6 +1574,7 @@ static struct ttm_bo_driver amdgpu_bo_driver = {
.move = &amdgpu_bo_move,
.verify_access = &amdgpu_verify_access,
.move_notify = &amdgpu_bo_move_notify,
+ .release_notify = &amdgpu_bo_release_notify,
.fault_reserve_notify = &amdgpu_bo_fault_reserve_notify,
.io_mem_reserve = &amdgpu_ttm_io_mem_reserve,
.io_mem_free = &amdgpu_ttm_io_mem_free,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
index caa76c693700..bccb8c49e597 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
@@ -38,6 +38,8 @@
#define AMDGPU_GTT_MAX_TRANSFER_SIZE 512
#define AMDGPU_GTT_NUM_TRANSFER_WINDOWS 2
+#define AMDGPU_POISON 0xd0bed0be
+
struct amdgpu_mman {
struct ttm_bo_device bdev;
bool mem_global_referenced;
--
2.17.1
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