On Thu, Aug 25, 2022 at 2:38 AM Si-Wei Liu <si-wei....@oracle.com> wrote: > > > > On 8/23/2022 9:27 PM, Jason Wang wrote: > > > > 在 2022/8/20 01:13, Eugenio Pérez 写道: > >> It was returned as error before. Instead of it, simply update the > >> corresponding field so qemu can send it in the migration data. > >> > >> Signed-off-by: Eugenio Pérez <epere...@redhat.com> > >> --- > > > > > > Looks correct. > > > > Adding Si Wei for double check. > Hmmm, I understand why this change is needed for live migration, but > this would easily cause userspace out of sync with the kernel for other > use cases, such as link down or userspace fallback due to vdpa ioctl > error. Yes, these are edge cases.
The link down case is not possible at this moment because that cvq command does not call virtio_net_handle_ctrl_iov. A similar treatment than mq would be needed when supported, and the call to virtio_net_set_status will be avoided. I'll double check device initialization ioctl failure with n->curr_queue_pairs > 1 in the destination, but I think we should be safe. > Not completely against it, but I > wonder if there's a way we can limit the change scope to live migration > case only? > The reason to update the device model is to send the curr_queue_pairs to the destination in a backend agnostic way. To send it otherwise would limit the live migration possibilities, but sure we can explore another way. Thanks!
