[PATCH 2/2] drm/amdgpu: allow higher level PD invalidations

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Allow partial invalidation on unallocated PDs. This is useful when we
need to silence faults to stop interrupt floods on Vega.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 8119f32ca94d..0f79c17118bf 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1467,9 +1467,8 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
 			 * smaller than the address shift. Go to the next
 			 * child entry and try again.
 			 */
-			if (!amdgpu_vm_pt_descendant(adev, &cursor))
-				return -ENOENT;
-			continue;
+			if (amdgpu_vm_pt_descendant(adev, &cursor))
+				continue;
 		} else if (frag >= parent_shift) {
 			/* If the fragment size is even larger than the parent
 			 * shift we should go up one level and check it again.
@@ -1480,8 +1479,19 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
 		}
 
 		pt = cursor.entry->base.bo;
-		if (!pt)
-			return -ENOENT;
+		if (!pt) {
+			/* We need all PDs and PTs for mapping something, */
+			if (flags & AMDGPU_PTE_VALID)
+				return -ENOENT;
+
+			/* but unmapping something can happen at a higher
+			 * level. */
+			if (!amdgpu_vm_pt_ancestor(&cursor))
+				return -EINVAL;
+
+			pt = cursor.entry->base.bo;
+			shift = parent_shift;
+		}
 
 		/* Looks good so far, calculate parameters for the update */
 		incr = (uint64_t)AMDGPU_GPU_PAGE_SIZE << shift;
@@ -1495,6 +1505,9 @@ static int amdgpu_vm_update_ptes(struct amdgpu_vm_update_params *params,
 			uint64_t upd_end = min(entry_end, frag_end);
 			unsigned nptes = (upd_end - frag_start) >> shift;
 
+			/* This can happen when we set higher level PDs to
+			 * silent to stop fault floods. */
+			nptes = max(nptes, 1u);
 			amdgpu_vm_update_flags(params, pt, cursor.level,
 					       pe_start, dst, nptes, incr,
 					       flags | AMDGPU_PTE_FRAG(frag));
-- 
2.14.1

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