On Fri, Dec 16, 2022 at 11:33:49AM +0800, Jason Wang wrote: > 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
Sounds minor enough, I'll queue, pls fix with a patch on top. > > + 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 > >
