Re: [RFC v3 06/29] virtio-net: Honor VIRTIO_CONFIG_S_DEVICE_STOPPED

[Jason Wang]

在 2021/5/26 上午9:06, Jason Wang 写道:
> 在 2021/5/20 上午12:28, Eugenio Pérez 写道:
> > So the guest can stop and start net device. It implements the RFC
> > https://lists.oasis-open.org/archives/virtio-comment/202012/msg00027.html 
> >
> >
> > To stop (as "pause") the device is required to migrate status and vring
> > addresses between device and SVQ.
> >
> > This is a WIP commit: as with VIRTIO_F_QUEUE_STATE, is introduced in
> > virtio_config.h before of even proposing for the kernel, with no feature
> > flag, and, with no checking in the device. It also needs a modified
> > vp_vdpa driver that supports to set and retrieve status.
> >
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > ---
> >   include/standard-headers/linux/virtio_config.h | 2 ++
> >   hw/net/virtio-net.c                            | 4 +++-
> >   2 files changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/standard-headers/linux/virtio_config.h 
> > b/include/standard-headers/linux/virtio_config.h
> > index 59fad3eb45..b3f6b1365d 100644
> > --- a/include/standard-headers/linux/virtio_config.h
> > +++ b/include/standard-headers/linux/virtio_config.h
> > @@ -40,6 +40,8 @@
> >   #define VIRTIO_CONFIG_S_DRIVER_OK    4
> >   /* Driver has finished configuring features */
> >   #define VIRTIO_CONFIG_S_FEATURES_OK    8
> > +/* Device is stopped */
> > +#define VIRTIO_CONFIG_S_DEVICE_STOPPED 32
> >   /* Device entered invalid state, driver must reset it */
> >   #define VIRTIO_CONFIG_S_NEEDS_RESET    0x40
> >   /* We've given up on this device. */
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index 96a3cc8357..2d3caea289 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -198,7 +198,9 @@ static bool virtio_net_started(VirtIONet *n, 
> > uint8_t status)
> >   {
> >       VirtIODevice *vdev = VIRTIO_DEVICE(n);
> >       return (status & VIRTIO_CONFIG_S_DRIVER_OK) &&
> > -        (n->status & VIRTIO_NET_S_LINK_UP) && vdev->vm_running;
> > +        (!(n->status & VIRTIO_CONFIG_S_DEVICE_STOPPED)) &&
> > +        (n->status & VIRTIO_NET_S_LINK_UP) &&
> > +        vdev->vm_running;
> >   }
> >     static void virtio_net_announce_notify(VirtIONet *net)
>
>
> It looks to me this is only the part of pause. 


And even for pause, I don't see anything that prevents rx/tx from being 
executed? (E.g virtio_net_handle_tx_bh or virtio_net_handle_rx).

Thanks


> We still need the resume?
>
> Thanks