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Subject: [PATCH 1/2] virtio-gpu: add resource create blob
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 guest memory. Many hypercalls are reused, since a image view into the blob resource is possible. Blob resources are both forward and backward looking. v2: Add TRANSFER_BLOB, SET_SCANOUT_BLOB, SCANOUT_FLUSH v3: Remove SCANOUT_FLUSH and add notes v4: Remove TRANSFER_BLOB for now. v5: clarify interactions with ATTACH_BACKING / DETACH_BACKING. This is to preserve the possibility of guest swap-in and guest swap-out, while acknowledging this feature may never be implemented and may not be applicable for all future planned values of `blob_mem` or context types. Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org> Acked-by: Chia-I Wu <olvaffe@gmail.com> --- virtio-gpu.tex | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) diff --git a/virtio-gpu.tex b/virtio-gpu.tex index e70532f..1c435cb 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 and using size-based blob resources is supported. \end{description} \subsection{Device configuration layout}\label{sec:Device Types / GPU Device / Device configuration layout} @@ -188,6 +189,8 @@ \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, + VIRTIO_GPU_CMD_SET_SCANOUT_BLOB, /* 3d commands (OpenGL) */ VIRTIO_GPU_CMD_CTX_CREATE = 0x0200, @@ -498,6 +501,101 @@ \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_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{nr_entries} guest +memory entries may be assigned to the resource. For default blob resources +(i.e, when \field{blob_mem} is VIRTIO_GPU_BLOB_MEM_HOST3D_GUEST), these +memory entries are used as a shadow buffer for the host memory. To +facilitate drivers that support swap-in and swap-out, \field{nr_entries} may +be zero and VIRTIO_GPU_CMD_RESOURCE_ATTACH_BACKING may be subsequently used. +VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING may be used to unassign memory entries. + +\field{blob_mem} can only be VIRTIO_GPU_BLOB_MEM_HOST3D and +VIRTIO_GPU_BLOB_MEM_HOST3D_GUEST if VIRTIO_GPU_F_VIRGL is supported. +VIRTIO_GPU_BLOB_MEM_GUEST is valid regardless whether VIRTIO_GPU_F_VIRGL +is supported or not. + +For VIRTIO_GPU_BLOB_MEM_HOST3D and VIRTIO_GPU_BLOB_MEM_HOST3D_GUEST, 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. + +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. + +\item[VIRTIO_GPU_CMD_SET_SCANOUT_BLOB] sets scanout parameters for a + blob resource. Request data is + \field{struct virtio_gpu_set_scanout_blob}. Response type is + VIRTIO_GPU_RESP_OK_NODATA. Support is optional and negotiated + using the VIRTIO_GPU_F_RESOURCE_BLOB feature flag. + +\begin{lstlisting} +struct virtio_gpu_set_scanout_blob { + struct virtio_gpu_ctrl_hdr hdr; + struct virtio_gpu_rect r; + le32 scanout_id; + le32 resource_id; + le32 width; + le32 height; + le32 format; + le32 padding; + le32 strides[4]; + le32 offsets[4]; +}; +\end{lstlisting} + +The rectangle \field{r} represents the portion of the blob resource being +displayed. The rest is the metadata associated with the blob resource. The +format MUST be one of \field{enum virtio_gpu_formats}. The format MAY be +compressed with header and data planes. + \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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