Hi Stefano, > From: Stefano Garzarella <sgarzare@xxxxxxxxxx> > Sent: Wednesday, October 27, 2021 9:17 PM > To: Parav Pandit <parav@xxxxxxxxxx> > Cc: Jason Wang <jasowang@xxxxxxxxxx>; Michael Tsirkin <mst@xxxxxxxxxx>; > Linux Virtualization <virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx>; Eli Cohen > <elic@xxxxxxxxxx> > Subject: Re: vDPA bus driver selection > > Hi Parav, > > On Wed, Oct 27, 2021 at 03:21:15PM +0000, Parav Pandit wrote: > >Hi Stefano, > > > >> From: Stefano Garzarella <sgarzare@xxxxxxxxxx> > >> Sent: Wednesday, October 27, 2021 8:04 PM > >> > >> Hi folks, > >> I was trying to understand if we have a way to specify which vDPA bus > >> driver (e.g. vhost-vdpa, virtio-vdpa) a device should use. > >> IIUC we don't have it, and the first registered driver is used when a > >> new device is registered. > >> > >> I was thinking if it makes sense to extend the management API to > >> specify which bus driver to use for a device. A use case could be for > >> example a single host handling VMs and bare-metal containers, so we > >> would have both virtio-vdpa and vhost-vdpa loaded and we want to > >> attach some devices to VMs through vhost-vdpa and others to containers > through virtio-vdpa. > >> > >> What do you think? > >> > >One option is, user keeps the drivers_autoprobe disabled for the vdpa > >bus using, > > > >$ vdpa/vdpa dev add mgmtdev vdpasim_net name vdpa0 mac > >00:11:22:33:44:55 $ echo 0 > /sys/bus/vdpa/drivers_autoprobe > > > >And after vdpa device creation, it manually binds to the desired driver > >such as, > > > >$ echo vdpa0 > /sys/bus/vdpa/drivers/virtio_vdpa/bind > >Or > >$ echo vdpa0 > /sys/bus/vdpa/drivers/vhost_vdpa/bind > > Cool, I didn't know that. This is very useful, but do you think it might be better > to integrate it with the netlink API and specify at creation which bus driver to > use? I think it is useful; for vduse case we need the ability to say "none" as well and when nothing specified it should be default driver. More than netlink, I think we need the ability in the core kernel to make this choice. I haven't explored what is already available to make that happen. If/once its available, I am sure it has more users than just vdpa. > > > > >In an case of VDUSE, it makes more sense to bind to the one of the > >above driver after user space has connected the use space backend to > >the kernel device. > > Yep, make sense. > > Thanks, > Stefano _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
