On Wed, Nov 17, 2010 at 08:38:25PM +0000, Stefan Hajnoczi wrote: > On Wed, Nov 17, 2010 at 6:01 PM, Michael S. Tsirkin <m...@redhat.com> wrote: > > On Wed, Nov 17, 2010 at 04:19:25PM +0000, Stefan Hajnoczi wrote: > >> The v4 version includes: > >> * Simpler start/stop ioeventfd mechanism using bool ioeventfd_started > >> state > >> * Support for migration > >> * Handle deassign race condition to avoid dropping a virtqueue kick > >> * Add missing kvm_enabled() check to kvm_has_many_ioeventfds() > >> * Documentation updates for qdev -device with ioeventfd=on|off > > > > Anthony, could you pls remind me what did you say > > about need to stop these threads on migration vmstop? > > Or am I confusing this with something else? > > Two points about the VM change state: > 1. It is used to bring up virtio-ioeventfd on the destination host > after migration. > 2. It handles the race condition where a virtqueue kick is dropped > because we deassign the ioeventfd on the source host. > > So I've implemented the VM change state to get correct migration behavior. > > The discussion you had with Anthony was more about events happening > while the VM is paused and how that could interfere with guest state > for migration IIRC. > > Stefan
Exactly. Could your patches cause a situation where block virtio ring is used after migration stopped a VM? -- MST
