From: "Michael S. Tsirkin" <mst@redhat.com>
To: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Thomas Graf <tgraf@suug.ch>,
linux-kernel@vger.kernel.org,
Rusty Russell <rusty@rustcorp.com.au>,
virtualization@lists.linux-foundation.org,
linux-scsi@vger.kernel.org, linux-s390@vger.kernel.org,
v9fs-developer@lists.sourceforge.net, netdev@vger.kernel.org,
kvm@vger.kernel.org, Amit Shah <amit.shah@redhat.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
"David S. Miller" <davem@davemloft.net>,
Paolo Bonzini <pbonzini@redhat.com>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v4 13/25] virtio_console: enable VQs early
Date: Mon, 20 Oct 2014 17:04:11 +0300 [thread overview]
Message-ID: <20141020140410.GA10994@redhat.com> (raw)
In-Reply-To: <20141020133555.GA27111@redhat.com>
On Mon, Oct 20, 2014 at 04:35:55PM +0300, Michael S. Tsirkin wrote:
> On Mon, Oct 20, 2014 at 02:42:23PM +0200, Cornelia Huck wrote:
> > On Mon, 20 Oct 2014 13:07:50 +0100
> > Thomas Graf <tgraf@suug.ch> wrote:
> >
> > > On 10/13/14 at 10:50am, Michael S. Tsirkin wrote:
> > > > virtio spec requires drivers to set DRIVER_OK before using VQs.
> > > > This is set automatically after probe returns, virtio console violated this
> > > > rule by adding inbufs, which causes the VQ to be used directly within
> > > > probe.
> > > >
> > > > To fix, call virtio_device_ready before using VQs.
> > > >
> > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > > ---
> > > > drivers/char/virtio_console.c | 2 ++
> > > > 1 file changed, 2 insertions(+)
> > > >
> > > > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> > > > index b585b47..6ebe8f6 100644
> > > > --- a/drivers/char/virtio_console.c
> > > > +++ b/drivers/char/virtio_console.c
> > > > @@ -1449,6 +1449,8 @@ static int add_port(struct ports_device *portdev, u32 id)
> > > > spin_lock_init(&port->outvq_lock);
> > > > init_waitqueue_head(&port->waitqueue);
> > > >
> > > > + virtio_device_ready(portdev->vdev);
> > > > +
> > > > /* Fill the in_vq with buffers so the host can send us data. */
> > > > nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
> > > > if (!nr_added_bufs) {
> > >
> > > Seems like probe and add_port() now both set VIRTIO_CONFIG_S_DRIVER_OK
> >
> > I think we need to set this in the probe function instead, otherwise we
> > fail for multiqueue (which also wants to use the control queue early).
> >
> > Completely untested patch below; I can send this with proper s-o-b if
> > it helps.
> >
> > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> > index bfa6400..cf7a561 100644
> > --- a/drivers/char/virtio_console.c
> > +++ b/drivers/char/virtio_console.c
> > @@ -1449,8 +1449,6 @@ static int add_port(struct ports_device *portdev, u32 id)
> > spin_lock_init(&port->outvq_lock);
> > init_waitqueue_head(&port->waitqueue);
> >
> > - virtio_device_ready(portdev->vdev);
> > -
> > /* Fill the in_vq with buffers so the host can send us data. */
> > nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
> > if (!nr_added_bufs) {
> > @@ -2026,6 +2024,8 @@ static int virtcons_probe(struct virtio_device *vdev)
> > spin_lock_init(&portdev->ports_lock);
> > INIT_LIST_HEAD(&portdev->ports);
> >
> > + virtio_device_ready(portdev->vdev);
> > +
> > if (multiport) {
> > unsigned int nr_added_bufs;
> >
>
> I wanted to set DRIVER_OK as late as possible, to both reduce
> the chance it can fail after DRIVER_OK and to reduce the risk of
> introducing a regression since old qemu might only start sending
> interrupts after DRIVER_OK is set.
>
> So I wanted everything completely initialized before DRIVER_OK.
>
> You patch makes sense to me since nothing can fail,
> and we won't get interrupts before we add inbufs.
>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
>
> Testig will report shortly, pls send with sob line.
Sure enough, this helps:
Tested-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Pls repost as a top-level patch.
> --
> MST
next prev parent reply other threads:[~2014-10-20 14:01 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-13 7:48 [PATCH v4 00/25] virtio: fix spec compliance issues Michael S. Tsirkin
2014-10-13 7:48 ` [PATCH v4 01/25] virtio_pci: fix virtio spec compliance on restore Michael S. Tsirkin
2014-10-13 7:48 ` [PATCH v4 02/25] virtio: unify config_changed handling Michael S. Tsirkin
2014-10-13 7:48 ` [PATCH v4 03/25] virtio-pci: move freeze/restore to virtio core Michael S. Tsirkin
2014-10-15 7:05 ` Paul Bolle
2014-10-13 7:50 ` [PATCH v4 04/25] virtio: defer config changed notifications Michael S. Tsirkin
2014-10-14 0:31 ` Rusty Russell
2014-10-14 8:59 ` Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 05/25] virtio_blk: drop config_enable Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 06/25] virtio-blk: drop config_mutex Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 07/25] virtio_net: drop config_enable Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 08/25] virtio-net: drop config_mutex Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 09/25] virtio_net: minor cleanup Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 10/25] virtio: add API to enable VQs early Michael S. Tsirkin
2014-11-11 0:45 ` Andy Grover
2014-11-11 6:15 ` Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 11/25] virtio_net: " Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 12/25] virtio_blk: " Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 13/25] virtio_console: " Michael S. Tsirkin
2014-10-20 12:07 ` Thomas Graf
2014-10-20 12:42 ` Cornelia Huck
2014-10-20 13:10 ` Thomas Graf
2014-10-20 13:35 ` Michael S. Tsirkin
2014-10-20 13:58 ` [PATCH] virtio_console: move early VQ enablement Cornelia Huck
2014-10-20 14:05 ` Michael S. Tsirkin
2014-10-20 17:09 ` Josh Boyer
2014-11-11 2:24 ` Dave Airlie
2014-10-20 14:04 ` Michael S. Tsirkin [this message]
2014-10-20 13:10 ` [PATCH v4 13/25] virtio_console: enable VQs early Michael S. Tsirkin
2014-10-20 13:12 ` Thomas Graf
2014-10-20 13:14 ` Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 14/25] 9p/trans_virtio: " Michael S. Tsirkin
2014-10-13 7:50 ` [PATCH v4 15/25] virtio_net: fix use after free on allocation failure Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 16/25] virtio_scsi: move kick event out from virtscsi_init Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 17/25] virtio_blk: enable VQs early on restore Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 18/25] virtio_scsi: " Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 19/25] virtio_console: " Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 20/25] virtio_net: " Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 21/25] virito_scsi: use freezable WQ for events Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 22/25] virtio_scsi: fix race on device removal Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 23/25] virtio_balloon: enable VQs early on restore Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 24/25] virtio_scsi: drop scan callback Michael S. Tsirkin
2014-10-13 7:51 ` [PATCH v4 25/25] virtio-rng: refactor probe error handling Michael S. Tsirkin
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