From: Felix Kuehling <Felix.Kuehling@xxxxxxx> [ Upstream commit 90ca78deb004abe75b5024968a199acb96bb70f9 ] This fixes an intermittent bug where a root PD clear operation still in progress could overwrite a PDE update done by the CPU, resulting in a VM fault. Fixes: 108b4d928c03 ("drm/amd/amdgpu: Update VM function pointer") Reported-by: Jay Cornwall <Jay.Cornwall@xxxxxxx> Tested-by: Jay Cornwall <Jay.Cornwall@xxxxxxx> Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx> Reviewed-by: Christian König <christian.koenig@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index 6d9252a27916..06242096973c 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -2996,10 +2996,17 @@ int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm, !amdgpu_gmc_vram_full_visible(&adev->gmc)), "CPU update of VM recommended only for large BAR system\n"); - if (vm->use_cpu_for_update) + if (vm->use_cpu_for_update) { + /* Sync with last SDMA update/clear before switching to CPU */ + r = amdgpu_bo_sync_wait(vm->root.base.bo, + AMDGPU_FENCE_OWNER_UNDEFINED, true); + if (r) + goto free_idr; + vm->update_funcs = &amdgpu_vm_cpu_funcs; - else + } else { vm->update_funcs = &amdgpu_vm_sdma_funcs; + } dma_fence_put(vm->last_update); vm->last_update = NULL; vm->is_compute_context = true; -- 2.25.1