On 11/09/2016 01:44 PM, Felipe Franciosi wrote: > Following the recent refactor of virtio notfiers [1], more specifically > the patch that uses virtio_bus_set_host_notifier [2] by default, core > virtio code requires 'ioeventfd_started' to be set to true/false when > the host notifiers are configured. Because not all vhost devices were > update (eg. vhost-scsi) to use the new interface, this value is always > set to false. > > When booting a guest with a vhost-scsi backend controller, SeaBIOS will > initially configure the device which sets all notifiers. The guest will > continue to boot fine until the kernel virtio-scsi driver reinitialises > the device causing a stop followed by another start. Since > ioeventfd_started was never set to true, the 'stop' operation triggered > by virtio_bus_set_host_notifier() will not result in a call to > virtio_pci_ioeventfd_assign(assign=false). This leaves the memory > regions with stale notifiers and results on the next start triggering > the following assertion: > > kvm_mem_ioeventfd_add: error adding ioeventfd: File exists > Aborted > > This patch updates ioeventfd_started whenever the notifiers are set or > cleared, fixing this issue. > > Signed-off-by: Felipe Franciosi <fel...@nutanix.com>
This also fixes vhost-net after reboot on s390/kvm for me Tested-by: Christian Borntraeger <borntrae...@de.ibm.com> > > [1] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07748.html > [2] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07760.html > --- > v1->v2: > - Update ioeventfd_started in vhost_dev_enable/disable_notifiers() > instead of vhost_scsi_start/stop(). > - Reword the commit message accordingly. > --- > hw/virtio/vhost.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c > index 131f164..1290963 100644 > --- a/hw/virtio/vhost.c > +++ b/hw/virtio/vhost.c > @@ -1205,6 +1205,7 @@ int vhost_dev_enable_notifiers(struct vhost_dev *hdev, > VirtIODevice *vdev) > goto fail_vq; > } > } > + VIRTIO_BUS(qbus)->ioeventfd_started = true; > > return 0; > fail_vq: > @@ -1239,6 +1240,7 @@ void vhost_dev_disable_notifiers(struct vhost_dev > *hdev, VirtIODevice *vdev) > } > assert (r >= 0); > } > + VIRTIO_BUS(qbus)->ioeventfd_started = false; > virtio_device_start_ioeventfd(vdev); > } >
