[PATCH v7 2/4] drm/virtgpu api: add blob userptr resource

[Honglei Huang]

Add DRM ioctl flags and a userptr address field so userspace can
request a blob backed by an existing process mapping.

UAPI changes:
- Add guest-only VIRTGPU_BLOB_FLAG_USE_USERPTR and
  VIRTGPU_BLOB_FLAG_USERPTR_RDONLY flags
- Add a userptr field to drm_virtgpu_resource_create_blob

These flags select guest pin behavior in the ioctl. They are not
part of the virtio CREATE_BLOB wire ABI, so mask them out in
virtio_gpu_cmd_resource_create_blob().

Signed-off-by: Honglei Huang <honghuan@xxxxxxx>
---
 drivers/gpu/drm/virtio/virtgpu_vq.c | 6 +++++-
 include/uapi/drm/virtgpu_drm.h      | 9 +++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index c02c03c10d..6830673309 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -1494,7 +1494,11 @@ virtio_gpu_cmd_resource_create_blob(struct virtio_gpu_device *vgdev,
 	cmd_p->hdr.ctx_id = cpu_to_le32(params->ctx_id);
 	cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
 	cmd_p->blob_mem = cpu_to_le32(params->blob_mem);
-	cmd_p->blob_flags = cpu_to_le32(params->blob_flags);
+	/* Guest-only flags stay off the wire. */
+	cmd_p->blob_flags = cpu_to_le32(params->blob_flags &
+			(VIRTIO_GPU_BLOB_FLAG_USE_MAPPABLE |
+			 VIRTIO_GPU_BLOB_FLAG_USE_SHAREABLE |
+			 VIRTIO_GPU_BLOB_FLAG_USE_CROSS_DEVICE));
 	cmd_p->blob_id = cpu_to_le64(params->blob_id);
 	cmd_p->size = cpu_to_le64(params->size);
 	cmd_p->nr_entries = cpu_to_le32(nents);
diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
index 95587e12ae..62c4b8f19b 100644
--- a/include/uapi/drm/virtgpu_drm.h
+++ b/include/uapi/drm/virtgpu_drm.h
@@ -186,6 +186,9 @@ struct drm_virtgpu_resource_create_blob {
 #define VIRTGPU_BLOB_FLAG_USE_MAPPABLE     0x0001
 #define VIRTGPU_BLOB_FLAG_USE_SHAREABLE    0x0002
 #define VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE 0x0004
+/* Guest-only flags */
+#define VIRTGPU_BLOB_FLAG_USE_USERPTR      0x0008
+#define VIRTGPU_BLOB_FLAG_USERPTR_RDONLY   0x0010
 	/* zero is invalid blob_mem */
 	__u32 blob_mem;
 	__u32 blob_flags;
@@ -205,6 +208,12 @@ struct drm_virtgpu_resource_create_blob {
 #define DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING        0x0001
 	__u32 blob_hints;
 	__u32 pad2;
+
+	/*
+	 * userptr: guest userspace memory address for VIRTGPU_BLOB_FLAG_USE_USERPTR.
+	 * Must be 0 if VIRTGPU_BLOB_FLAG_USE_USERPTR is not set.
+	 */
+	__u64 userptr;
 };
 
 #define VIRTGPU_CONTEXT_PARAM_CAPSET_ID       0x0001
-- 
2.34.1