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Re: [Qemu-devel] [PATCH 2/5] virtio: Migrate the "start_on_kick" flag
From: |
Greg Kurz |
Subject: |
Re: [Qemu-devel] [PATCH 2/5] virtio: Migrate the "start_on_kick" flag |
Date: |
Mon, 3 Jun 2019 23:25:23 +0200 |
On Mon, 3 Jun 2019 17:03:06 -0400
"Michael S. Tsirkin" <address@hidden> wrote:
> On Mon, Jun 03, 2019 at 10:16:39PM +0200, Greg Kurz wrote:
> > On Wed, 29 May 2019 15:09:52 +0800
> > address@hidden wrote:
> >
> > > From: Xie Yongji <address@hidden>
> > >
> > > We should migrate the "start_on_kick" flag so that we
> > > would not miss starting device on kicking at startup
> > > after migration.
> > >
> >
> > Hmm... IIUC "start_on_kick" means "virtio 1.0 transitional device that has
> > not been started yet", ie:
> >
> > !vdev->started &&
> > (virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1) &&
> > !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1))
>
> Or a legacy device I guess?
>
Do you mean "start_on_kick" should be set for both legacy
and virtio 1.0 transitional devices ?
> > If so, not sure why you need this extra field in the first place, but
> > you probably don't need to migrate it. Just recalculate in a post load
> > callback.
> >
> > > Signed-off-by: Xie Yongji <address@hidden>
> > > ---
> > > hw/virtio/virtio.c | 19 +++++++++++++++++++
> > > 1 file changed, 19 insertions(+)
> > >
> > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> > > index fc8fca81ad..4d4ff67791 100644
> > > --- a/hw/virtio/virtio.c
> > > +++ b/hw/virtio/virtio.c
> > > @@ -1802,6 +1802,13 @@ static bool virtio_started_needed(void *opaque)
> > > return vdev->started;
> > > }
> > >
> > > +static bool virtio_start_on_kick_needed(void *opaque)
> > > +{
> > > + VirtIODevice *vdev = opaque;
> > > +
> > > + return vdev->start_on_kick;
> > > +}
> > > +
> > > static const VMStateDescription vmstate_virtqueue = {
> > > .name = "virtqueue_state",
> > > .version_id = 1,
> > > @@ -1941,6 +1948,17 @@ static const VMStateDescription
> > > vmstate_virtio_started = {
> > > }
> > > };
> > >
> > > +static const VMStateDescription vmstate_virtio_start_on_kick = {
> > > + .name = "virtio/start_on_kick",
> > > + .version_id = 1,
> > > + .minimum_version_id = 1,
> > > + .needed = &virtio_start_on_kick_needed,
> > > + .fields = (VMStateField[]) {
> > > + VMSTATE_BOOL(start_on_kick, VirtIODevice),
> > > + VMSTATE_END_OF_LIST()
> > > + }
> > > +};
> > > +
> > > static const VMStateDescription vmstate_virtio = {
> > > .name = "virtio",
> > > .version_id = 1,
> > > @@ -1957,6 +1975,7 @@ static const VMStateDescription vmstate_virtio = {
> > > &vmstate_virtio_broken,
> > > &vmstate_virtio_extra_state,
> > > &vmstate_virtio_started,
> > > + &vmstate_virtio_start_on_kick,
> > > NULL
> > > }
> > > };