On Thu, Dec 15, 2022 at 9:50 PM Longpeng(Mike) <longpe...@huawei.com> wrote: > > From: Longpeng <longpe...@huawei.com> > > Signed-off-by: Longpeng <longpe...@huawei.com> > --- > .../devices/vhost-vdpa-generic-device.rst | 68 +++++++++++++++++++ > 1 file changed, 68 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..24c825ef1a > --- /dev/null > +++ b/docs/system/devices/vhost-vdpa-generic-device.rst > @@ -0,0 +1,68 @@ > + > +========================= > +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. > + > + > +Requirements > +------------ > +Linux 5.18+ > +iproute2/vdpa 5.12.0+ > + > + > +Examples > +-------- > + > +1. Prepare the vhost-vDPA backends, here is an example using vdpa_sim_blk > + device: > + > +:: > + host# modprobe vhost_vdpa > + host# modprobe vdpa_sim_blk
Nit: it's probably better to add driver binding steps here. > + host# vdpa dev add mgmtdev vdpasim_blk name blk0 > + (...you can see the vhost-vDPA device under /dev directory now...) And then the vhost char dev name could be fetch via ls /sys/bus/vdpa/device/blk0/vhost-vdpa* With the above changes. Acked-by: Jason Wang <jasow...@redhat.com> Thanks > + host# ls -l /dev/vhost-vdpa-* > + crw------- 1 root root 236, 0 Nov 2 00:49 /dev/vhost-vdpa-0 > + > +Note: > +It needs some vendor-specific steps to provision the vDPA device if you're > +using real HW devices, such as loading the vendor-specific vDPA driver and > +binding the device to the driver. > + > + > +2. Start the virtual machine: > + > +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 >
