[RFC,v3,2/2] virtio-gpu: add the ability to export resources

Commit Message

David Stevens Feb. 7, 2020, 7:40 a.m. UTC

Signed-off-by: David Stevens <[e-mail]>
---
 virtio-gpu.tex | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

Comments

Gerd Hoffmann Feb. 12, 2020, 11:50 a.m. UTC | #1

On Fri, Feb 07, 2020 at 04:40:33PM +0900, David Stevens wrote:
> Signed-off-by: David Stevens <[e-mail]>
> ---
>  virtio-gpu.tex | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/virtio-gpu.tex b/virtio-gpu.tex
> index af4ca61..e950ad3 100644
> --- a/virtio-gpu.tex
> +++ b/virtio-gpu.tex
> @@ -186,12 +186,16 @@ \subsubsection{Device Operation: Request header}\label{sec:Device Types / GPU De
>          VIRTIO_GPU_CMD_UPDATE_CURSOR = 0x0300,
>          VIRTIO_GPU_CMD_MOVE_CURSOR,
>  
> +        /* misc commands */
> +        VIRTIO_GPU_CMD_RESOURCE_ASSIGN_UUID = 0x0400,

I'd suggest to move that to the "2d commands" section (which isn't
really "2d" but more "not 3d").

We also need a feature flag signaling support for the new command.

Otherwise this looks ok to me.

Are there any patches and/or attempts to merge/discuss upstream?
Specifically for handling the uuids for dma-bufs in linux (guest side)?
I suspect there will be some discussions on this and having at least
some plan upstream can agree on would be good.

cheers,
  Gerd

Patch

diff --git a/virtio-gpu.tex b/virtio-gpu.tex
index af4ca61..e950ad3 100644
--- a/virtio-gpu.tex
+++ b/virtio-gpu.tex
@@ -186,12 +186,16 @@  \subsubsection{Device Operation: Request header}\label{sec:Device Types / GPU De
         VIRTIO_GPU_CMD_UPDATE_CURSOR = 0x0300,
         VIRTIO_GPU_CMD_MOVE_CURSOR,
 
+        /* misc commands */
+        VIRTIO_GPU_CMD_RESOURCE_ASSIGN_UUID = 0x0400,
+
         /* success responses */
         VIRTIO_GPU_RESP_OK_NODATA = 0x1100,
         VIRTIO_GPU_RESP_OK_DISPLAY_INFO,
         VIRTIO_GPU_RESP_OK_CAPSET_INFO,
         VIRTIO_GPU_RESP_OK_CAPSET,
         VIRTIO_GPU_RESP_OK_EDID,
+        VIRTIO_GPU_RESP_OK_RESOURCE_ASSIGN_UUID,
 
         /* error responses */
         VIRTIO_GPU_RESP_ERR_UNSPEC = 0x1200,
@@ -454,6 +458,31 @@  \subsubsection{Device Operation: controlq}\label{sec:Device Types / GPU Device /
 This detaches any backing pages from a resource, to be used in case of
 guest swapping or object destruction.
 
+\item[VIRTIO_GPU_CMD_RESOURCE_ASSIGN_UUID] Creates an exported object from
+  a resource. Request data is \field{struct
+    virtio_gpu_resource_assign_uuid}.  Response type is
+  VIRTIO_GPU_RESP_OK_RESOURCE_ASSIGN_UUID, response data is \field{struct
+    virtio_gpu_resp_resource_assign_uuid}.
+
+\begin{lstlisting}
+struct virtio_gpu_resource_assign_uuid {
+        struct virtio_gpu_ctrl_hdr hdr;
+        le32 resource_id;
+        le32 padding;
+};
+
+struct virtio_gpu_resp_resource_assign_uuid {
+        struct virtio_gpu_ctrl_hdr hdr;
+        u8 uuid[16];
+};
+\end{lstlisting}
+
+The response contains a UUID which identifies the exported object created from
+the host private resource. Note that if the resource has an attached backing,
+modifications made to the host private resource through the exported object by
+other devices are not visible in the attached backing until they are transferred
+into the backing.
+
 \end{description}
 
 \subsubsection{Device Operation: cursorq}\label{sec:Device Types / GPU Device / Device Operation / Device Operation: cursorq}