Re: [virtio-comment] [PATCH 1/2] virtio-gpu: add resource create blob

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Apr 21, 2020 at 05:55:30PM -0700, Gurchetan Singh wrote:
> Blob resources are size-based containers for host, guest, or
> host+guest allocations.  These resources are designed with
> mulit-process 3D support in mind, but also usable in virtio-gpu 2d
> with system memory allocation (also known as dumb allocation, but
> since that's reserved in a DRM/KMS world, went with system).
> 
> Many hypercalls are reused, since a image view into the blob resource
> is possible.
> 
> Blob resources are both forward and backward looking.
> 
> Co-authored-by: Gerd Hoffman <kraxel@redhat.com>
> Co-authored-by: Chia-I-Wu <olvaffe@gmail.com>

Pls just use standard Signed-off-by.


> Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
> ---
>  virtio-gpu.tex | 101 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 101 insertions(+)
> 
> diff --git a/virtio-gpu.tex b/virtio-gpu.tex
> index e70532f..6f374bd 100644
> --- a/virtio-gpu.tex
> +++ b/virtio-gpu.tex
> @@ -36,6 +36,7 @@ \subsection{Feature bits}\label{sec:Device Types / GPU Device / Feature bits}
>  \item[VIRTIO_GPU_F_VIRGL (0)] virgl 3D mode is supported.
>  \item[VIRTIO_GPU_F_EDID  (1)] EDID is supported.
>  \item[VIRTIO_GPU_F_RESOURCE_UUID (2)] assigning resources UUIDs for export to other virtio devices is supported.
> +\item[VIRTIO_GPU_F_RESOURCE_BLOB (3)] creating size-based blob resources is supported.
>  \end{description}
>  
>  \subsection{Device configuration layout}\label{sec:Device Types / GPU Device / Device configuration layout}
> @@ -188,6 +189,7 @@ \subsubsection{Device Operation: Request header}\label{sec:Device Types / GPU De
>          VIRTIO_GPU_CMD_GET_CAPSET,
>          VIRTIO_GPU_CMD_GET_EDID,
>          VIRTIO_GPU_CMD_RESOURCE_ASSIGN_UUID,
> +        VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB,
>  
>          /* 3d commands (OpenGL) */
>          VIRTIO_GPU_CMD_CTX_CREATE = 0x0200,
> @@ -498,6 +500,105 @@ \subsubsection{Device Operation: controlq}\label{sec:Device Types / GPU Device /
>  other devices are not visible in the attached backing until they are transferred
>  into the backing.
>  
> +\item[VIRTIO_GPU_CMD_RESOURCE_CREATE_BLOB] Creates a virtio-gpu blob
> +  resource. Request data is \field{struct
> +  virtio_gpu_resource_create_blob}, followed by \field{struct
> +  virtio_gpu_mem_entry} entries. Response type is
> +  VIRTIO_GPU_RESP_OK_NODATA. Support is optional and negotiated
> +  using the VIRTIO_GPU_F_RESOURCE_BLOB feature flag.
> +
> +\begin{lstlisting}
> +#define VIRTIO_GPU_BLOB_MEM_GUEST             0x0001
> +#define VIRTIO_GPU_BLOB_MEM_HOST3D            0x0002
> +#define VIRTIO_GPU_BLOB_MEM_HOST3D_GUEST      0x0003
> +#define VIRTIO_GPU_BLOB_MEM_HOSTSYS           0x0004
> +#define VIRTIO_GPU_BLOB_MEM_HOSTSYS_GUEST     0x0005
> +
> +#define VIRTIO_GPU_BLOB_FLAG_USE_MAPPABLE     0x0001
> +#define VIRTIO_GPU_BLOB_FLAG_USE_SHAREABLE    0x0002
> +#define VIRTIO_GPU_BLOB_FLAG_USE_CROSS_DEVICE 0x0004
> +
> +struct virtio_gpu_resource_create_blob {
> +       struct virtio_gpu_ctrl_hdr hdr;
> +       le32 resource_id;
> +       le32 blob_mem;
> +       le32 blob_flags;
> +       le32 nr_entries;
> +       le64 blob_id;
> +       le64 size;
> +};
> +
> +\end{lstlisting}
> +
> +A blob resource is a container for:
> +
> +  \begin{itemize*}
> +  \item a guest memory allocation (referred to as a
> +  "guest-only blob resource").
> +  \item a host memory allocation (referred to as a
> +  "host-only blob resource").
> +  \item a guest memory and host memory allocation (referred
> +  to as a "default blob resource").
> +  \end{itemize*}
> +
> +The memory properties of the blob resource MUST be described by
> +\field{blob_mem}, which MUST be non-zero.
> +
> +For default and guest-only blob resources, \field{nents} guest
> +system pages are assigned to the resource.  For default blob
> +resources, these guest pages are used for transfer operations.
> +
> +Host allocations depend on whether VIRTIO_GPU_F_VIRGL is supported.
> +If VIRTIO_GPU_F_VIRGL is not supported, then:
> +
> +  \begin{itemize*}
> +  \item \field{blob_mem} MUST be VIRTIO_GPU_BLOB_MEM_HOSTSYS for host-only
> +  blob resources
> +  \item \field{blob_mem} MUST be VIRTIO_GPU_BLOB_MEM_HOSTSYS_GUEST for
> +  default blob resources
> +  \end{itemize*}
> +
> +For the above above cases, host system memory is allocated by the device.
> +
> +If VIRTIO_GPU_F_VIRGL is supported, then:
> +
> +  \begin{itemize*}
> +  \item \field{blob_mem} MUST be VIRTIO_GPU_BLOB_MEM_HOST3D for host-only
> +  blob resources
> +  \item \field{blob_mem} MUST be VIRTIO_GPU_BLOB_MEM_HOST3D_GUEST for
> +  default resources
> +  \end{itemize*}
> +
> +For the above cases, the virtio-gpu resource MUST be created from the
> +rendering context local object identified by the \field{blob_id}. The
> +actual allocation is done via VIRTIO_GPU_CMD_SUBMIT_3D.
> +
> +VIRTIO_GPU_BLOB_MEM_GUEST is valid regardless whether VIRTIO_GPU_F_VIRGL
> +is supported or not.
> +
> +The driver MUST inform the device if the blob resource is used for
> +memory access, sharing between driver instances and/or sharing with
> +other devices. This is done via the \field{blob_flags} field.
> +
> +If VIRTIO_GPU_F_VIRGL is set, both VIRTIO_GPU_CMD_TRANSFER_TO_HOST_3D
> +and VIRTIO_GPU_CMD_TRANSFER_FROM_HOST_3D may be used to update the
> +resource. There is no restriction on the image/buffer view the driver
> +has on the blob resource.
> +
> +VIRTIO_GPU_CMD_TRANSFER_TO_HOST_2D, VIRTIO_GPU_CMD_SET_SCANOUT and
> +VIRTIO_GPU_CMD_RESOURCE_FLUSH MAY be used with blob resources as well,
> +subject to the following restrictions:
> +
> +  \begin{itemize*}
> +  \item the driver MUST have a 4-byte per pixel 2D image view of the
> +        blob resource.
> +  \item the device MUST have a 4-byte per pixel 2D image view of the
> +        blob resource, or create one if does not exist.
> +  \end{itemize*}
> +
> +For host-only blob resources, transfer operations MAY synchronize
> +caches.
> +
>  \end{description}
>  
>  \subsubsection{Device Operation: controlq (3d)}\label{sec:Device Types / GPU Device / Device Operation / Device Operation: controlq (3d)}
> -- 
> 2.24.1
> 
> 
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