An internal buffer is used when processing VIRTIO_BLK_T_ZONE_REPORT
requests. The buffer's size is controlled by the guest. A large value
can result in g_malloc() failure and the QEMU process aborts, resulting
in a Denial of Service (DoS) (most likely in cases where an untrusted
guest application or a nested guest with virtio-blk passthrough is able
to abort QEMU).