On Wed, May 30, 2018 at 04:26:30PM +0000, Duyck, Alexander H wrote: > On Wed, 2018-05-30 at 19:22 +0300, Michael S. Tsirkin wrote: > > On Wed, May 30, 2018 at 09:10:57AM -0700, Alexander Duyck wrote: > > > On Wed, May 30, 2018 at 1:55 AM, Tiwei Bie <tiwei.bie@xxxxxxxxx> wrote: > > > > There is a new feature bit allocated in virtio spec to > > > > support SR-IOV (Single Root I/O Virtualization): > > > > > > > > https://github.com/oasis-tcs/virtio-spec/issues/11 > > > > > > > > This patch enables the support for this feature bit in > > > > virtio driver. > > > > > > > > Signed-off-by: Tiwei Bie <tiwei.bie@xxxxxxxxx> > > > > > > So from a quick glance it looks like we are leaving SR-IOV enabled if > > > the driver is removed. Do we want to have that behavior or should we > > > be adding the code to disable SR-IOV and free the VFs on driver > > > removal? > > > > Could pci core handle it for us somehow? > > Maybe, but it would require changes to the pci core to do it. > > The problem is some drivers want to leave the VFs there since the PF > doesn't really do anything, or they have the option of essentially > putting the VFs into a standby state when the PF is gone. > > My main concern is do we care if VFs are allocated and then somebody > removes the driver and binds a different driver to the interface? If > not then this code and be left as is, but I just wanted to be certain > since I know this isn't just enabling SR-IOV we are having to do a > number of other checks against the virtio device. Well the spec says features have to be negotiated, and since we reset the device when we unbind from it I think it's a given we should keep a driver bound to the PF. IOW until we are sure we need the capability to keep it enabled, let's disable it to be safe. -- MST
