[Qemu-devel] [RFC v2 0/9] virtio: avoid exit() when device enters invalid states

[Stefan Hajnoczi]

v2:
 * Add VIRTIO_CONFIG_S_NEEDS_RESET notification for VIRTIO 1.0 [Cornelia]
   (Note I've sent a Linux virtio_config.h patch to get the constant added to
   the headers.)
 * Split int -> unsigned int change into separate commit [Fam]
 * Fix double "index" typo in commit description [Fam]

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 (9):
  virtio: fix stray tab character
  include: update virtio_config.h Linux header
  virtio: stop virtqueue processing if device is broken
  virtio: handle virtqueue_map_desc() errors
  virtio: handle virtqueue_get_avail_bytes() errors
  virtio: use unsigned int for virtqueue_get_avail_bytes() index
  virtio: handle virtqueue_read_next_desc() errors
  virtio: handle virtqueue_num_heads() errors
  virtio: handle virtqueue_get_head() errors

 hw/virtio/virtio.c                             | 204 +++++++++++++++++++------
 include/hw/virtio/virtio.h                     |   3 +
 include/standard-headers/linux/virtio_config.h |   2 +
 3 files changed, 162 insertions(+), 47 deletions(-)

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2.5.5