On Sat, Nov 12, 2022 at 10:40 PM Longpeng(Mike) <longpeng2@huawei.com> wrote:
>
> From: Longpeng <longpeng2@huawei.com>
>
> Signed-off-by: Longpeng <longpeng2@huawei.com>
> ---
> .../devices/vhost-vdpa-generic-device.rst | 46 +++++++++++++++++++
> 1 file changed, 46 insertions(+)
> create mode 100644 docs/system/devices/vhost-vdpa-generic-device.rst
>
> diff --git a/docs/system/devices/vhost-vdpa-generic-device.rst b/docs/system/devices/vhost-vdpa-generic-device.rst
> new file mode 100644
> index 0000000000..d6db9af755
> --- /dev/null
> +++ b/docs/system/devices/vhost-vdpa-generic-device.rst
> @@ -0,0 +1,46 @@
> +
> +=========================
> +vhost-vDPA generic device
> +=========================
> +
> +This document explains the usage of the vhost-vDPA generic device.
> +
> +Description
> +-----------
> +
> +vDPA(virtio data path acceleration) device is a device that uses a datapath
> +which complies with the virtio specifications with vendor specific control
> +path.
> +
> +QEMU provides two types of vhost-vDPA devices to enable the vDPA device, one
> +is type sensitive which means QEMU needs to know the actual device type
> +(e.g. net, blk, scsi) and another is called "vhost-vDPA generic device" which
> +is type insensitive.
> +
> +The vhost-vDPA generic device builds on the vhost-vdpa subsystem and virtio
> +subsystem. It is quite small, but it can support any type of virtio device.
> +
> +Examples
> +--------
> +
> +Prepare the vhost-vDPA backends first:
Nit: here we'd better first say, it needs some vendor specific steps
to provision vDPA and bind it to vhost-vDPA driver. Then we can see
that in under dev directory.
Thanks
> +
> +::
> + host# ls -l /dev/vhost-vdpa-*
> + crw------- 1 root root 236, 0 Nov 2 00:49 /dev/vhost-vdpa-0
> +
> +Start QEMU with virtio-mmio bus:
> +
> +::
> + host# qemu-system \
> + -M microvm -m 512 -smp 2 -kernel ... -initrd ... \
> + -device vhost-vdpa-device,vhostdev=/dev/vhost-vdpa-0 \
> + ...
> +
> +Start QEMU with virtio-pci bus:
> +
> +::
> + host# qemu-system \
> + -M pc -m 512 -smp 2 \
> + -device vhost-vdpa-device-pci,vhostdev=/dev/vhost-vdpa-0 \
> + ...
> --
> 2.23.0
>