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Re: [Qemu-devel] [RFC v2 3/9] virtio: stop virtqueue processing if devic
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [RFC v2 3/9] virtio: stop virtqueue processing if device is broken |
Date: |
Wed, 30 Mar 2016 13:21:53 +0100 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Tue, Mar 29, 2016 at 06:58:03PM +0200, Cornelia Huck wrote:
> On Tue, 29 Mar 2016 17:12:55 +0100
> Stefan Hajnoczi <address@hidden> wrote:
>
> > QEMU prints an error message and exits when the device enters an invalid
> > state. Terminating the process is heavy-handed. The guest may still be
> > able to function even if there is a bug in a virtio guest driver.
> >
> > Moreover, exiting is a bug in nested virtualization where a nested guest
> > could DoS other nested guests by killing a pass-through virtio device.
> > I don't think this configuration is possible today but it is likely in
> > the future.
> >
> > If the broken flag is set, do not process virtqueues or write back used
> > descriptors. The broken flag can be cleared again by resetting the
> > device.
> >
> > Signed-off-by: Stefan Hajnoczi <address@hidden>
> > ---
> > hw/virtio/virtio.c | 39 +++++++++++++++++++++++++++++++++++++++
> > include/hw/virtio/virtio.h | 3 +++
> > 2 files changed, 42 insertions(+)
>
> > +void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt,
> > ...)
> > +{
> > + va_list ap;
> > +
> > + va_start(ap, fmt);
> > + error_vreport(fmt, ap);
> > + va_end(ap);
> > +
> > + vdev->broken = true;
> > +
> > + if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
> > + vdev->status |= VIRTIO_CONFIG_S_NEEDS_RESET;
>
> virtio_set_status()?
Will fix in next revision
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- [Qemu-devel] [RFC v2 0/9] virtio: avoid exit() when device enters invalid states, Stefan Hajnoczi, 2016/03/29
- [Qemu-devel] [RFC v2 1/9] virtio: fix stray tab character, Stefan Hajnoczi, 2016/03/29
- [Qemu-devel] [RFC v2 2/9] include: update virtio_config.h Linux header, Stefan Hajnoczi, 2016/03/29
- [Qemu-devel] [RFC v2 3/9] virtio: stop virtqueue processing if device is broken, Stefan Hajnoczi, 2016/03/29
- [Qemu-devel] [RFC v2 6/9] virtio: use unsigned int for virtqueue_get_avail_bytes() index, Stefan Hajnoczi, 2016/03/29
- [Qemu-devel] [RFC v2 4/9] virtio: handle virtqueue_map_desc() errors, Stefan Hajnoczi, 2016/03/29
- [Qemu-devel] [RFC v2 5/9] virtio: handle virtqueue_get_avail_bytes() errors, Stefan Hajnoczi, 2016/03/29
- [Qemu-devel] [RFC v2 9/9] virtio: handle virtqueue_get_head() errors, Stefan Hajnoczi, 2016/03/29
- [Qemu-devel] [RFC v2 7/9] virtio: handle virtqueue_read_next_desc() errors, Stefan Hajnoczi, 2016/03/29
- [Qemu-devel] [RFC v2 8/9] virtio: handle virtqueue_num_heads() errors, Stefan Hajnoczi, 2016/03/29