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virtio: update MemoryRegionCaches when guest negotiates features

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Because the cache is sized to include the rings and the event indices,
negotiating the VIRTIO_RING_F_EVENT_IDX feature will result in the size
of the cache changing.  And because MemoryRegionCache accesses are
range-checked, if we skip this we end up with an assertion failure.
This happens with OpenBSD 6.3.

Reported-by: Fam Zheng <famz@redhat.com>
Fixes: 97cd965c07
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Paolo Bonzini 2018-08-23 14:21:23 +02:00 committed by Michael S. Tsirkin
parent dbb6da8ba7
commit db812c4073
1 changed files with 13 additions and 2 deletions
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13
hw/virtio/virtio.c
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@ -2006,6 +2006,7 @@ static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val)
int virtio_set_features(VirtIODevice *vdev, uint64_t val)
{
int ret;
/*
* The driver must not attempt to set features after feature negotiation
* has finished.
@ -2013,7 +2014,17 @@ int virtio_set_features(VirtIODevice *vdev, uint64_t val)
if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) {
return -EINVAL;
}
return virtio_set_features_nocheck(vdev, val);
ret = virtio_set_features_nocheck(vdev, val);
if (!ret && virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
/* VIRTIO_RING_F_EVENT_IDX changes the size of the caches. */
int i;
for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
if (vdev->vq[i].vring.num != 0) {
virtio_init_region_cache(vdev, i);
}
}
}
return ret;
}
int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)