drm/amdgpu: add new INFO ioctl query for the last GPU page fault

Add a interface to query the last GPU page fault for the process.
Useful for debugging context lost errors.

v2: split vmhub representation between kernel and userspace
v3: add locking when fetching fault info in INFO IOCTL

Mesa MR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23238
libdrm MR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23238

Cc: samuel.pitoiset@gmail.com
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Guchun Chen <guchun.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -113,9 +113,10 @@
  *            gl1c_cache_size, gl2c_cache_size, mall_size, enabled_rb_pipes_mask_hi
  *   3.53.0 - Support for GFX11 CP GFX shadowing
  *   3.54.0 - Add AMDGPU_CTX_QUERY2_FLAGS_RESET_IN_PROGRESS support
+ * - 3.55.0 - Add AMDGPU_INFO_GPUVM_FAULT query
  */
 #define KMS_DRIVER_MAJOR	3
-#define KMS_DRIVER_MINOR	54
+#define KMS_DRIVER_MINOR	55
 #define KMS_DRIVER_PATCHLEVEL	0
 
 /*

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

@@ -1224,6 +1224,26 @@ int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 		return copy_to_user(out, max_ibs,
 				    min((size_t)size, sizeof(max_ibs))) ? -EFAULT : 0;
 	}
+	case AMDGPU_INFO_GPUVM_FAULT: {
+		struct amdgpu_fpriv *fpriv = filp->driver_priv;
+		struct amdgpu_vm *vm = &fpriv->vm;
+		struct drm_amdgpu_info_gpuvm_fault gpuvm_fault;
+		unsigned long flags;
+
+		if (!vm)
+			return -EINVAL;
+
+		memset(&gpuvm_fault, 0, sizeof(gpuvm_fault));
+
+		xa_lock_irqsave(&adev->vm_manager.pasids, flags);
+		gpuvm_fault.addr = vm->fault_info.addr;
+		gpuvm_fault.status = vm->fault_info.status;
+		gpuvm_fault.vmhub = vm->fault_info.vmhub;
+		xa_unlock_irqrestore(&adev->vm_manager.pasids, flags);
+
+		return copy_to_user(out, &gpuvm_fault,
+				    min((size_t)size, sizeof(gpuvm_fault))) ? -EFAULT : 0;
+	}
 	default:
 		DRM_DEBUG_KMS("Invalid request %d\n", info->query);
 		return -EINVAL;

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

@@ -2756,7 +2756,21 @@ void amdgpu_vm_update_fault_cache(struct amdgpu_device *adev,
 	if (vm) {
 		vm->fault_info.addr = addr;
 		vm->fault_info.status = status;
-		vm->fault_info.vmhub = vmhub;
+		if (AMDGPU_IS_GFXHUB(vmhub)) {
+			vm->fault_info.vmhub = AMDGPU_VMHUB_TYPE_GFX;
+			vm->fault_info.vmhub |=
+				(vmhub - AMDGPU_GFXHUB_START) << AMDGPU_VMHUB_IDX_SHIFT;
+		} else if (AMDGPU_IS_MMHUB0(vmhub)) {
+			vm->fault_info.vmhub = AMDGPU_VMHUB_TYPE_MM0;
+			vm->fault_info.vmhub |=
+				(vmhub - AMDGPU_MMHUB0_START) << AMDGPU_VMHUB_IDX_SHIFT;
+		} else if (AMDGPU_IS_MMHUB1(vmhub)) {
+			vm->fault_info.vmhub = AMDGPU_VMHUB_TYPE_MM1;
+			vm->fault_info.vmhub |=
+				(vmhub - AMDGPU_MMHUB1_START) << AMDGPU_VMHUB_IDX_SHIFT;
+		} else {
+			WARN_ONCE(1, "Invalid vmhub %u\n", vmhub);
+		}
 	}
 	xa_unlock_irqrestore(&adev->vm_manager.pasids, flags);
 }

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h

@@ -124,9 +124,16 @@ struct amdgpu_mem_stats;
  * layout: max 8 GFXHUB + 4 MMHUB0 + 1 MMHUB1
  */
 #define AMDGPU_MAX_VMHUBS			13
-#define AMDGPU_GFXHUB(x)			(x)
-#define AMDGPU_MMHUB0(x)			(8 + x)
-#define AMDGPU_MMHUB1(x)			(8 + 4 + x)
+#define AMDGPU_GFXHUB_START			0
+#define AMDGPU_MMHUB0_START			8
+#define AMDGPU_MMHUB1_START			12
+#define AMDGPU_GFXHUB(x)			(AMDGPU_GFXHUB_START + (x))
+#define AMDGPU_MMHUB0(x)			(AMDGPU_MMHUB0_START + (x))
+#define AMDGPU_MMHUB1(x)			(AMDGPU_MMHUB1_START + (x))
+
+#define AMDGPU_IS_GFXHUB(x) ((x) >= AMDGPU_GFXHUB_START && (x) < AMDGPU_MMHUB0_START)
+#define AMDGPU_IS_MMHUB0(x) ((x) >= AMDGPU_MMHUB0_START && (x) < AMDGPU_MMHUB1_START)
+#define AMDGPU_IS_MMHUB1(x) ((x) >= AMDGPU_MMHUB1_START && (x) < AMDGPU_MAX_VMHUBS)
 
 /* Reserve 2MB at top/bottom of address space for kernel use */
 #define AMDGPU_VA_RESERVED_SIZE			(2ULL << 20)

include/uapi/drm/amdgpu_drm.h

@@ -906,6 +906,8 @@ struct drm_amdgpu_cs_chunk_cp_gfx_shadow {
 	#define AMDGPU_INFO_VIDEO_CAPS_ENCODE		1
 /* Query the max number of IBs per gang per submission */
 #define AMDGPU_INFO_MAX_IBS			0x22
+/* query last page fault info */
+#define AMDGPU_INFO_GPUVM_FAULT			0x23
 
 #define AMDGPU_INFO_MMR_SE_INDEX_SHIFT	0
 #define AMDGPU_INFO_MMR_SE_INDEX_MASK	0xff
@@ -1231,6 +1233,20 @@ struct drm_amdgpu_info_video_caps {
 	struct drm_amdgpu_info_video_codec_info codec_info[AMDGPU_INFO_VIDEO_CAPS_CODEC_IDX_COUNT];
 };
 
+#define AMDGPU_VMHUB_TYPE_MASK			0xff
+#define AMDGPU_VMHUB_TYPE_SHIFT			0
+#define AMDGPU_VMHUB_TYPE_GFX			0
+#define AMDGPU_VMHUB_TYPE_MM0			1
+#define AMDGPU_VMHUB_TYPE_MM1			2
+#define AMDGPU_VMHUB_IDX_MASK			0xff00
+#define AMDGPU_VMHUB_IDX_SHIFT			8
+
+struct drm_amdgpu_info_gpuvm_fault {
+	__u64 addr;
+	__u32 status;
+	__u32 vmhub;
+};
+
 /*
  * Supported GPU families
  */