[PATCH 2/3] drm/amdgpu: fix a bug for flag table_freed

[Eric Huang]

table_freed will be always true when mapping a memory with size
bigger than 2MB. Using a check of turnning valid PDE into PTE
will resolve the issue.

Signed-off-by: Eric Huang <jinhuieric.huang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 0dee2e8797c7..b1bdc89cb5d1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1553,6 +1553,21 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
 			 */
 			nptes = max(nptes, 1u);
 
+			/* Fix a page fault in a corner case of
+			 * turning valid PDE entry to PTE entry
+			 * for huge page mapping
+			 */
+			if (cursor.level < AMDGPU_VM_PTB) {
+				int i;
+				for (i = 0; i < nptes; i++) {
+					uint64_t value = 0;
+					vm->update_funcs->get_pt_entry(pt,
+							pe_start + (i * 8), &value);
+					if (value & AMDGPU_PTE_VALID)
+						params->table_freed = true;
+				}
+			}
+
 			trace_amdgpu_vm_update_ptes(params, frag_start, upd_end,
 						    nptes, dst, incr, upd_flags,
 						    vm->task_info.pid,
@@ -1584,7 +1599,6 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
 			while (cursor.pfn < frag_start) {
 				amdgpu_vm_free_pts(adev, params->vm, &cursor);
 				amdgpu_vm_pt_next(adev, &cursor);
-				params->table_freed = true;
 			}
 
 		} else if (frag >= shift) {
-- 
2.25.1