Am 01.12.2010 06:59, schrieb Michael S. Tsirkin: > On Wed, Dec 01, 2010 at 01:45:09PM +0800, Jason Wang wrote: >> Michael S. Tsirkin writes: >> > Avoid sending out packets, and modifying >> > device state, when VM is stopped. >> > Add assert statements to verify this does not happen. >> > >> > Avoid scheduling bh when vhost-net is started. >> > >> > Stop bh when driver disabled bus mastering >> > (we must not access memory after this). >> > >> > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> >> > >> >> There's no need to disable it bh we call qemu_aio_flush() after >> vm_state_notify() in do_vm_stop(). > > Yes, but bh can resubmit itself, so flush is not enough. > Note that vm stop is not the only reason to avoid > running bh: when vhost-net is enabled we should avoid it too. > Makes sense?
If I understand correctly, qemu_aio_flush() is supposed to also execute the resubmitted BH, so that you really end up with an empty BH list. Kevin
