tree 74699f13536b3066785670735a67b6315dc7825e
parent 90488aaaf37f7cf3b49f834b4fd9a66bf773d7ec
author Michael S. Tsirkin <mst@redhat.com> 1524245063 +0300
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1525212785 -0700

virtio_console: free buffers after reset

commit a7a69ec0d8e4a58be7db88d33cbfa2912807bb2b upstream.

Console driver is out of spec. The spec says:
	A driver MUST NOT decrement the available idx on a live
	virtqueue (ie. there is no way to “unexpose” buffers).
and it does exactly that by trying to detach unused buffers
without doing a device reset first.

Defer detaching the buffers until device unplug.

Of course this means we might get an interrupt for
a vq without an attached port now. Handle that by
discarding the consumed buffer.

Reported-by: Tiwei Bie <tiwei.bie@intel.com>
Fixes: b3258ff1d6 ("virtio: Decrement avail idx on buffer detach")
Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>