Re: [PATCHv2] qemu-kvm: fix crash on reboot with vhost-net

[Juan Quintela <quintela@redhat.com>]

"Michael S. Tsirkin" <mst@redhat.com> wrote:
> 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>
> ---
>
> Changes from v1:
> 	Separate APIs to set and unset notifiers
> 	Test and clear notifier before destroying it
>
>  hw/msix.c       |   40 +++++++++++++++++++++++++++++++++++-----
>  hw/msix.h       |    1 +
>  hw/virtio-pci.c |    7 +++++--
>  3 files changed, 41 insertions(+), 7 deletions(-)

Acked-by: Juan Quintela <quintela@redhat.com>

This patch addresses the issues that I pointed in previous mail and
fixes the problem at hand.

Creating a better API for interaction between virtio-pci <-> msix still
needs more work/thought, already discussed that with mst.

Later, Juan.