Re: [Qemu-stable] [PATCH] virtio-bus: Plug devices after features are negotiated

[Cornelia Huck]

On Tue, 13 Sep 2016 09:08:04 +0200
Maxime Coquelin <address@hidden> wrote:

> On 09/12/2016 09:58 PM, Michael S. Tsirkin wrote:
> > On Mon, Sep 12, 2016 at 08:22:50PM +0200, Maxime Coquelin wrote:
> >>
> >>
> >> On 09/12/2016 10:51 AM, Cornelia Huck wrote:
> >>> On Sat, 10 Sep 2016 10:23:37 +0200
> >>> Maxime Coquelin <address@hidden> wrote:
> >>>
> >>>>> Currently, devices are plugged before features are negotiated.
> >>>>> If the backend doesn't support VIRTIO_F_VERSION_1, the transport
> >>>>> need to rewind some settings.
> >>>>>
> >>>>> This is the case for CCW, for which a post_plugged callback had
> >>>>> been introduced, where max_rev field is just updated if
> >>>>> VIRTIO_F_VERSION_1 is not supported by the backend.
> >>>>> For PCI, implementing the post_plugged would be much more
> >>> s/the//
> >>>
> >>>>> complicated, so it needs to know whether the backend supports
> >>>>> VIRTIO_F_VERSION_1 at plug time.
> >>>>>
> >>>>> Currently, nothing is done for PCI. Modern capabilitities get
> >>>>> exposed to the guest even if VIRTIO_F_VERSION_1 is not supported
> >>>>> by the backend, which confuses the guest.
> >>>>>
> >>>>> This patch proposes to replace existing post_plugged solution
> >>> Nit: The patch does not propose anything, it just does it :)
> >>>
> >> Michael,
> >>
> >> Should I send a v2 fixing the above comments, or you can handle them
> >> when applying the patch?
> >>
> >> Thanks,
> >> Maxime
> >
> >
> > It's easier if you post v2 including all acks.
> Ok, v2 is ready, waiting to collect some acks.

In the meanwhile, I've verified that everything works as expected as
well with an old host kernel (3.18) and your patch for ccw. Therefore,

Tested-by: Cornelia Huck <address@hidden> [ccw]
Reviewed-by: Cornelia Huck <address@hidden>