[PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

From: Honglei Huang

Date: Fri Sep 18 2026 - 06:05:14 EST


Integrate userptr into the blob resource creation ioctl.

- A non-zero userptr selects virtio_gpu_userptr_create()
- Reject userptr unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
- Reject VIRTGPU_BLOB_FLAG_USE_READONLY unless the device
advertised VIRTIO_GPU_F_BLOB_READONLY
- Advertise VIRTGPU_PARAM_USERPTR and VIRTGPU_PARAM_BLOB_READONLY

Signed-off-by: Honglei Huang <honghuan@xxxxxxx>
---
drivers/gpu/drm/virtio/virtgpu_debugfs.c | 1 +
drivers/gpu/drm/virtio/virtgpu_ioctl.c | 35 ++++++++++++++++++++----
drivers/gpu/drm/virtio/virtgpu_kms.c | 8 ++++--
3 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_debugfs.c b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
index 3a68a16b58..b8b9b40584 100644
--- a/drivers/gpu/drm/virtio/virtgpu_debugfs.c
+++ b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
@@ -55,6 +55,7 @@ static int virtio_gpu_features(struct seq_file *m, void *data)
vgdev->has_resource_assign_uuid);

virtio_gpu_add_bool(m, "blob resources", vgdev->has_resource_blob);
+ virtio_gpu_add_bool(m, "blob readonly", vgdev->has_blob_readonly);
virtio_gpu_add_bool(m, "context init", vgdev->has_context_init);
virtio_gpu_add_int(m, "cap sets", vgdev->num_capsets);
virtio_gpu_add_int(m, "scanouts", vgdev->num_scanouts);
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 3d8e4ccdb7..3dc058e50e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -36,7 +36,10 @@

#define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
- VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
+ VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
+ VIRTGPU_BLOB_FLAG_USE_READONLY)
+
+#define VIRTGPU_BLOB_HINT_MASK DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING

/* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
static void virtio_gpu_create_context_locked(struct virtio_gpu_device *vgdev,
@@ -122,6 +125,12 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data,
return -ENOENT;
value = vgdev->blob_alignment;
break;
+ case VIRTGPU_PARAM_USERPTR:
+ value = 1;
+ break;
+ case VIRTGPU_PARAM_BLOB_READONLY:
+ value = vgdev->has_blob_readonly ? 1 : 0;
+ break;
default:
return -EINVAL;
}
@@ -453,11 +462,23 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
return -EINVAL;

+ if (rc_blob->blob_hints & ~VIRTGPU_BLOB_HINT_MASK)
+ return -EINVAL;
+
if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
if (!vgdev->has_resource_assign_uuid)
return -EINVAL;
}

+ if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_READONLY) {
+ if (!vgdev->has_blob_readonly)
+ return -EINVAL;
+ }
+
+ if (rc_blob->userptr &&
+ rc_blob->blob_mem != VIRTGPU_BLOB_MEM_GUEST)
+ return -EINVAL;
+
switch (rc_blob->blob_mem) {
case VIRTGPU_BLOB_MEM_GUEST:
*guest_blob = true;
@@ -495,6 +516,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
params->blob = true;
params->blob_flags = rc_blob->blob_flags;
params->blob_hints = rc_blob->blob_hints;
+ params->userptr = rc_blob->userptr;

if (vgdev->has_blob_alignment &&
!IS_ALIGNED(params->size, vgdev->blob_alignment))
@@ -518,9 +540,10 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
struct drm_virtgpu_resource_create_blob *rc_blob = data;

- if (verify_blob(vgdev, vfpriv, &params, rc_blob,
- &guest_blob, &host3d_blob))
- return -EINVAL;
+ ret = verify_blob(vgdev, vfpriv, &params, rc_blob,
+ &guest_blob, &host3d_blob);
+ if (ret)
+ return ret;

if (vgdev->has_virgl_3d)
virtio_gpu_create_context(dev, file);
@@ -538,7 +561,9 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
vfpriv->ctx_id, NULL, NULL);
}

- if (guest_blob)
+ if (guest_blob && params.userptr)
+ ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
+ else if (guest_blob)
ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
else if (!guest_blob && host3d_blob)
ret = virtio_gpu_vram_create(vgdev, &params, &bo);
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 1d4d3bf46a..06c2bded49 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -249,15 +249,19 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
vgdev->blob_alignment = blob_alignment;
}

+ if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_BLOB_READONLY))
+ vgdev->has_blob_readonly = true;
+
DRM_INFO("features: %cvirgl %cedid %cresource_blob %chost_visible",
vgdev->has_virgl_3d ? '+' : '-',
vgdev->has_edid ? '+' : '-',
vgdev->has_resource_blob ? '+' : '-',
vgdev->has_host_visible ? '+' : '-');

- DRM_INFO("features: %ccontext_init %cblob_alignment\n",
+ DRM_INFO("features: %ccontext_init %cblob_alignment %cblob_readonly\n",
vgdev->has_context_init ? '+' : '-',
- vgdev->has_blob_alignment ? '+' : '-');
+ vgdev->has_blob_alignment ? '+' : '-',
+ vgdev->has_blob_readonly ? '+' : '-');

ret = virtio_gpu_find_vqs(vgdev);
if (ret) {
--
2.34.1