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From: Stefan Hajnoczi <stefanha@redhat.com>
To: qemu-devel@nongnu.org
Cc: Fam Zheng <famz@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>
Subject: [Qemu-devel] [RFC 0/7] virtio: avoid exit() when device enters invalid states
Date: Thu, 24 Mar 2016 17:56:47 +0000	[thread overview]
Message-ID: <1458842214-11450-1-git-send-email-stefanha@redhat.com> (raw)

The virtio code calls exit() when the device enters an invalid state.  This
means invalid vring indices and descriptor chains kill the VM.  See the patch
descriptions for why this is a bad thing.

When the virtio device is in the broken state calls to virtqueue_pop() and
friends will pretend the virtqueue is empty.  This means the device will become
isolated from guest activity until it is reset again.

RFC because two things are missing:
1. Live migration support (subsection for broken flag?)
2. Auditing devices and replacing exit() calls there too

Stefan Hajnoczi (7):
  virtio: fix stray tab character
  virtio: stop virtqueue processing if device is broken
  virtio: handle virtqueue_map_desc() errors
  virtio: handle virtqueue_get_avail_bytes() errors
  virtio: handle virtqueue_read_next_desc() errors
  virtio: handle virtqueue_num_heads() errors
  virtio: handle virtqueue_get_head() errors

 hw/virtio/virtio.c         | 199 ++++++++++++++++++++++++++++++++++-----------
 include/hw/virtio/virtio.h |   3 +
 2 files changed, 155 insertions(+), 47 deletions(-)

-- 
2.5.5

             reply	other threads:[~2016-03-24 17:57 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-24 17:56 Stefan Hajnoczi [this message]
2016-03-24 17:56 ` [Qemu-devel] [RFC 1/7] virtio: fix stray tab character Stefan Hajnoczi
2016-03-25  6:45   ` Fam Zheng
2016-03-24 17:56 ` [Qemu-devel] [RFC 2/7] virtio: stop virtqueue processing if device is broken Stefan Hajnoczi
2016-03-25  6:48   ` Fam Zheng
2016-03-29 11:12     ` Stefan Hajnoczi
2016-03-29  7:52   ` Cornelia Huck
2016-03-29 11:14     ` Stefan Hajnoczi
2016-03-24 17:56 ` [Qemu-devel] [RFC 3/7] virtio: handle virtqueue_map_desc() errors Stefan Hajnoczi
2016-03-24 17:56 ` [Qemu-devel] [RFC 4/7] virtio: handle virtqueue_get_avail_bytes() errors Stefan Hajnoczi
2016-03-24 17:56 ` [Qemu-devel] [RFC 5/7] virtio: handle virtqueue_read_next_desc() errors Stefan Hajnoczi
2016-03-25  7:01   ` Fam Zheng
2016-03-29 11:14     ` Stefan Hajnoczi
2016-03-24 17:56 ` [Qemu-devel] [RFC 6/7] virtio: handle virtqueue_num_heads() errors Stefan Hajnoczi
2016-03-25  7:03   ` Fam Zheng
2016-03-24 17:56 ` [Qemu-devel] [RFC 7/7] virtio: handle virtqueue_get_head() errors Stefan Hajnoczi

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