From: "Michael S. Tsirkin" <mst@redhat.com>
To: Ben Hutchings <ben@decadent.org.uk>
Cc: Amit Shah <amit.shah@redhat.com>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH RFC] virtio_pci: fix virtio spec compliance on restore
Date: Wed, 24 Sep 2014 14:59:13 +0300 [thread overview]
Message-ID: <20140924115913.GA32179@redhat.com> (raw)
In-Reply-To: <1411522047.3659.10.camel@decadent.org.uk>
On Wed, Sep 24, 2014 at 02:27:27AM +0100, Ben Hutchings wrote:
> On Tue, 2014-09-23 at 13:32 +0300, Michael S. Tsirkin wrote:
> > On restore, virtio pci does the following:
> > + set features
> > + init vqs etc - device can be used at this point!
> > + set ACKNOWLEDGE,DRIVER and DRIVER_OK status bits
> >
> > This is in violation of the virtio spec, which
> > requires the following order:
> > - ACKNOWLEDGE
> > - DRIVER
> > - init vqs
> > - DRIVER_OK
> >
> > Cc: stable@vger.kernel.org
> > Cc: Amit Shah <amit.shah@redhat.com>
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> [...]
>
> What concrete problem does this fix, such that it should be applied to
> stable branches?
>
> Ben.
It will break with hypervisors that assume spec compliant behaviour.
I would like this applied to stable branches so hypervisors don't
need to support broken behaviour forever.
--
MST
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Ben Hutchings <ben@decadent.org.uk>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Amit Shah <amit.shah@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH RFC] virtio_pci: fix virtio spec compliance on restore
Date: Wed, 24 Sep 2014 14:59:13 +0300 [thread overview]
Message-ID: <20140924115913.GA32179@redhat.com> (raw)
In-Reply-To: <1411522047.3659.10.camel@decadent.org.uk>
On Wed, Sep 24, 2014 at 02:27:27AM +0100, Ben Hutchings wrote:
> On Tue, 2014-09-23 at 13:32 +0300, Michael S. Tsirkin wrote:
> > On restore, virtio pci does the following:
> > + set features
> > + init vqs etc - device can be used at this point!
> > + set ACKNOWLEDGE,DRIVER and DRIVER_OK status bits
> >
> > This is in violation of the virtio spec, which
> > requires the following order:
> > - ACKNOWLEDGE
> > - DRIVER
> > - init vqs
> > - DRIVER_OK
> >
> > Cc: stable@vger.kernel.org
> > Cc: Amit Shah <amit.shah@redhat.com>
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> [...]
>
> What concrete problem does this fix, such that it should be applied to
> stable branches?
>
> Ben.
It will break with hypervisors that assume spec compliant behaviour.
I would like this applied to stable branches so hypervisors don't
need to support broken behaviour forever.
--
MST
next prev parent reply other threads:[~2014-09-24 11:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-23 10:32 [PATCH RFC] virtio_pci: fix virtio spec compliance on restore Michael S. Tsirkin
2014-09-23 10:32 ` Michael S. Tsirkin
2014-09-23 16:06 ` Eric Northup
2014-09-23 16:06 ` Eric Northup
2014-09-23 18:02 ` Michael S. Tsirkin
2014-09-23 18:02 ` Michael S. Tsirkin
2014-09-24 1:27 ` Ben Hutchings
2014-09-24 11:59 ` Michael S. Tsirkin [this message]
2014-09-24 11:59 ` Michael S. Tsirkin
2014-09-24 1:27 ` Ben Hutchings
2014-09-24 12:27 ` Amit Shah
2014-09-24 12:27 ` Amit Shah
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