From: Li Qiang Date: Sat, 19 Sep 2020 08:27:06 +0000 (-0700) Subject: virtio: update MemoryRegionCaches when guest set bad features X-Git-Tag: pull-nvme-20201102~84^2~28 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=2d69eba5fe52045b2c8b0d04fd3806414352afc1;p=qemu-nvme.git virtio: update MemoryRegionCaches when guest set bad features Current the 'virtio_set_features' only update the 'MemorRegionCaches' when the 'virtio_set_features_nocheck' return '0' which means it is not bad features. However the guest can still trigger the access of the used vring after set bad features. In this situation it will cause assert failure in 'ADDRESS_SPACE_ST_CACHED'. Buglink: https://bugs.launchpad.net/qemu/+bug/1890333 Fixes: db812c4073c7 ("virtio: update MemoryRegionCaches when guest negotiates features") Reported-by: Alexander Bulekov Signed-off-by: Li Qiang Message-Id: <20200919082706.6703-1-liq3ea@163.com> Reviewed-by: Paolo Bonzini Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index a2edb4f386..6f8f865aff 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2963,17 +2963,16 @@ int virtio_set_features(VirtIODevice *vdev, uint64_t val) return -EINVAL; } ret = virtio_set_features_nocheck(vdev, val); - if (!ret) { - if (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); - } + if (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); } } - + } + if (!ret) { if (!virtio_device_started(vdev, vdev->status) && !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { vdev->start_on_kick = true;