drm/amdgpu: add VRAM lost query

Allows userspace to figure out if VRAM was lost.
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NNicolai Hähnle <nicolai.haehnle@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c

@@ -763,6 +763,9 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
 		}
 		return copy_to_user(out, &ui32, min(size, 4u)) ? -EFAULT : 0;
 	}
+	case AMDGPU_INFO_VRAM_LOST_COUNTER:
+		ui32 = atomic_read(&adev->vram_lost_counter);
+		return copy_to_user(out, &ui32, min(size, 4u)) ? -EFAULT : 0;
 	default:
 		DRM_DEBUG_KMS("Invalid request %d\n", info->query);
 		return -EINVAL;

include/uapi/drm/amdgpu_drm.h

@@ -657,6 +657,7 @@ struct drm_amdgpu_cs_chunk_data {
 	#define AMDGPU_INFO_SENSOR_VDDGFX		0x7
 /* Number of VRAM page faults on CPU access. */
 #define AMDGPU_INFO_NUM_VRAM_CPU_PAGE_FAULTS	0x1E
+#define AMDGPU_INFO_VRAM_LOST_COUNTER		0x1F
 
 #define AMDGPU_INFO_MMR_SE_INDEX_SHIFT	0
 #define AMDGPU_INFO_MMR_SE_INDEX_MASK	0xff