[PATCH v6 2/4] drm/virtgpu api: add blob userptr resource

[Honglei Huang <honghuan@amd.com>]

From: Honglei Huang <Honglei1.Huang@amd.com>

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.

Signed-off-by: Honglei Huang <Honglei1.Huang@amd.com>
---
 include/uapi/drm/virtgpu_drm.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
index 95587e12ae..6171b4e230 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 +208,13 @@ 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.
+	 * The driver will pin the user pages and allow the host to access them.
+	 */
+	__u64 userptr;
 };
 
 #define VIRTGPU_CONTEXT_PARAM_CAPSET_ID       0x0001
-- 
2.34.1