Pull virtio fixes from Michael Tsirkin:
"Some bugfixes that seem important and safe enough to merge at the last
minute"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
virtio_balloon: fix another race between migration and ballooning
tools/virtio: add kmalloc_array stub
tools/virtio: add dma barrier stubs