drm/amdgpu: expose the VA above the hole to userspace

Let userspace know how much area we have above the 48bit VA hole on
Vega10.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -550,6 +550,7 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
 	}
 	case AMDGPU_INFO_DEV_INFO: {
 		struct drm_amdgpu_info_device dev_info = {};
+		uint64_t vm_size;
 
 		dev_info.device_id = dev->pdev->device;
 		dev_info.chip_rev = adev->rev_id;
@@ -577,10 +578,17 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
 			dev_info.ids_flags |= AMDGPU_IDS_FLAGS_FUSION;
 		if (amdgpu_sriov_vf(adev))
 			dev_info.ids_flags |= AMDGPU_IDS_FLAGS_PREEMPTION;
+
+		vm_size = adev->vm_manager.max_pfn * AMDGPU_GPU_PAGE_SIZE;
 		dev_info.virtual_address_offset = AMDGPU_VA_RESERVED_SIZE;
 		dev_info.virtual_address_max =
-			min(adev->vm_manager.max_pfn * AMDGPU_GPU_PAGE_SIZE,
-			    AMDGPU_VA_HOLE_START);
+			min(vm_size, AMDGPU_VA_HOLE_START);
+
+		vm_size -= AMDGPU_VA_RESERVED_SIZE;
+		if (vm_size > AMDGPU_VA_HOLE_START) {
+			dev_info.high_va_offset = AMDGPU_VA_HOLE_END;
+			dev_info.high_va_max = AMDGPU_VA_HOLE_END | vm_size;
+		}
 		dev_info.virtual_address_alignment = max((int)PAGE_SIZE, AMDGPU_GPU_PAGE_SIZE);
 		dev_info.pte_fragment_size = (1 << adev->vm_manager.fragment_size) * AMDGPU_GPU_PAGE_SIZE;
 		dev_info.gart_page_size = AMDGPU_GPU_PAGE_SIZE;

include/uapi/drm/amdgpu_drm.h

@@ -877,6 +877,10 @@ struct drm_amdgpu_info_device {
 	__u32 _pad1;
 	/* always on cu bitmap */
 	__u32 cu_ao_bitmap[4][4];
+	/** Starting high virtual address for UMDs. */
+	__u64 high_va_offset;
+	/** The maximum high virtual address */
+	__u64 high_va_max;
 };
 
 struct drm_amdgpu_info_hw_ip {