drm/amdgpu: fix user fence handling once more

Same problem as with the VM page tables. The user fence address must be
determined before the job is scheduled, not when the IB is executed.

This fixes a security problem where user fences could be used to overwrite
any part of VRAM.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

4 files changed, 9 insertions, 14 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index cd7d15941a83..4fc879e594aa 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1278,8 +1278,7 @@ struct amdgpu_job {
         uint32_t                oa_base, oa_size;
 
         /* user fence handling */
-        struct amdgpu_bo        *uf_bo;
-        uint32_t                uf_offset;
+        uint64_t                uf_addr;
         uint64_t                uf_sequence;
 
 };
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 95b248159947..475c95f670f8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -216,11 +216,8 @@ int amdgpu_cs_parser_init(struct amdgpu_cs_parser *p, void *data)
         if (ret)
                 goto free_all_kdata;
 
-        if (p->uf_entry.robj) {
-                p->job->uf_bo = amdgpu_bo_ref(p->uf_entry.robj);
-                p->job->uf_offset = uf_offset;
-        }
-
+        if (p->uf_entry.robj)
+                p->job->uf_addr = uf_offset;
         kfree(chunk_array);
         return 0;
 
@@ -502,6 +499,9 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
                 }
         }
 
+        if (p->uf_entry.robj)
+                p->job->uf_addr += amdgpu_bo_gpu_offset(p->uf_entry.robj);
+
 error_validate:
         if (r) {
                 amdgpu_vm_move_pt_bos_in_lru(p->adev, &fpriv->vm);
@@ -767,7 +767,7 @@ static int amdgpu_cs_ib_fill(struct amdgpu_device *adev,
         }
 
         /* UVD & VCE fw doesn't support user fences */
-        if (parser->job->uf_bo && (
+        if (parser->job->uf_addr && (
             parser->job->ring->type == AMDGPU_RING_TYPE_UVD ||
             parser->job->ring->type == AMDGPU_RING_TYPE_VCE))
                 return -EINVAL;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
index 34e35423b78e..0bf6c1b330be 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
@@ -203,11 +203,8 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
         }
 
         /* wrap the last IB with fence */
-        if (job && job->uf_bo) {
-                uint64_t addr = amdgpu_bo_gpu_offset(job->uf_bo);
-
-                addr += job->uf_offset;
-                amdgpu_ring_emit_fence(ring, addr, job->uf_sequence,
+        if (job && job->uf_addr) {
+                amdgpu_ring_emit_fence(ring, job->uf_addr, job->uf_sequence,
                                        AMDGPU_FENCE_FLAG_64BIT);
         }
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index b50a8450fcae..87b75d726ae8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -91,7 +91,6 @@ static void amdgpu_job_free_resources(struct amdgpu_job *job)
                 amdgpu_ib_free(job->adev, &job->ibs[i], f);
         fence_put(job->fence);
 
-        amdgpu_bo_unref(&job->uf_bo);
         amdgpu_sync_free(&job->sync);
 }