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>
  *            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
 
 /*
 
                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;
 
        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);
 }
 
  * 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)
 
        #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
        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
  */