qemu-kvm: fix crash on reboot with vhost-netqemu-kvm-0.12.4-gentoo-2qemu-kvm-0.12.4-gentoo

When vhost-net is disabled on reboot, we set msix mask notifier
to NULL to disable further mask/unmask notifications.
Code currently tries to pass this NULL to notifier,
leading to a crash.  The right thing to do is
to add explicit APIs to enable/disable notifications.
Now when disabling notifications:
- if vector is masked, we don't need to notify backend,
  just disable future notifications
- if vector is unmasked, invoke callback to unassign backend,
  then disable future notifications

This patch also polls notifier before closing it,
to make sure we don't lose events if poll callback
didn't have time to run.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

0 files changed, 0 insertions, 0 deletions