Re: [PATCH] amdkfd: MTYPE_UC for ext-coherent system memory

[Felix Kuehling]

On 2025-06-19 14:40, David Yat Sin wrote:

Set memory mtype to UC host memory when ext-coherent
flag is set and memory is registered as a SVM allocation.

Signed-off-by: David Yat Sin <david.yat...@amd.com>

Reviewed-by: Felix Kuehling <felix.kuehl...@amd.com>

---
  drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 16fb19800f9e..9dba0e4ae4b3 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -1282,7 +1282,7 @@ svm_range_get_pte_flags(struct kfd_node *node,
                                mapping_flags |= ext_coherent ? 
AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
                /* system memory accessed by the dGPU */
                } else {
-                       if (gc_ip_version < IP_VERSION(9, 5, 0))
+                       if (gc_ip_version < IP_VERSION(9, 5, 0) || ext_coherent)
                                mapping_flags |= AMDGPU_VM_MTYPE_UC;
                        else
                                mapping_flags |= AMDGPU_VM_MTYPE_NC;