Paolo Bonzini <pbonz...@redhat.com> writes:
> Commit b1f416aa8d870fab71030abc9401cfc77b948e8e breaks vhost_net
> because it always registers the virtio_pci_host_notifier_read() handler
> function on the ioeventfd, even when vhost_net.ko is using the ioeventfd.
> The result is both QEMU and vhost_net.ko polling on the same eventfd
> and the virtio_net.ko guest driver seeing inconsistent results:
>
> # ifconfig eth0 192.168.0.1 netmask 255.255.255.0
> virtio_net virtio0: output:id 0 is not a head!
>
> To fix this, proceed the same as we do for irqfd: add a parameter to
> virtio_queue_set_host_notifier_fd_handler and in that case only set
> the notifier, not the handler.
>
> Cc: Stefan Hajnoczi <stefa...@linux.vnet.ibm.com>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Applied. Thanks.
Regards,
Anthony Liguori
> ---
> hw/virtio-pci.c | 14 +++++++-------
> hw/virtio.c | 7 +++++--
> hw/virtio.h | 3 ++-
> 3 file modificati, 14 inserzioni(+), 10 rimozioni(-)
>
> diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
> index 3ab9747..6133626 100644
> --- a/hw/virtio-pci.c
> +++ b/hw/virtio-pci.c
> @@ -160,7 +160,7 @@ static int virtio_pci_load_queue(void * opaque, int n,
> QEMUFile *f)
> }
>
> static int virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,
> - int n, bool assign)
> + int n, bool assign, bool
> set_handler)
> {
> VirtQueue *vq = virtio_get_queue(proxy->vdev, n);
> EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
> @@ -173,13 +173,13 @@ static int
> virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,
> __func__, r);
> return r;
> }
> - virtio_queue_set_host_notifier_fd_handler(vq, true);
> + virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
> memory_region_add_eventfd(&proxy->bar, VIRTIO_PCI_QUEUE_NOTIFY, 2,
> true, n, notifier);
> } else {
> memory_region_del_eventfd(&proxy->bar, VIRTIO_PCI_QUEUE_NOTIFY, 2,
> true, n, notifier);
> - virtio_queue_set_host_notifier_fd_handler(vq, false);
> + virtio_queue_set_host_notifier_fd_handler(vq, false, false);
> event_notifier_cleanup(notifier);
> }
> return r;
> @@ -200,7 +200,7 @@ static void virtio_pci_start_ioeventfd(VirtIOPCIProxy
> *proxy)
> continue;
> }
>
> - r = virtio_pci_set_host_notifier_internal(proxy, n, true);
> + r = virtio_pci_set_host_notifier_internal(proxy, n, true, true);
> if (r < 0) {
> goto assign_error;
> }
> @@ -214,7 +214,7 @@ assign_error:
> continue;
> }
>
> - r = virtio_pci_set_host_notifier_internal(proxy, n, false);
> + r = virtio_pci_set_host_notifier_internal(proxy, n, false, false);
> assert(r >= 0);
> }
> proxy->ioeventfd_started = false;
> @@ -235,7 +235,7 @@ static void virtio_pci_stop_ioeventfd(VirtIOPCIProxy
> *proxy)
> continue;
> }
>
> - r = virtio_pci_set_host_notifier_internal(proxy, n, false);
> + r = virtio_pci_set_host_notifier_internal(proxy, n, false, false);
> assert(r >= 0);
> }
> proxy->ioeventfd_started = false;
> @@ -683,7 +683,7 @@ static int virtio_pci_set_host_notifier(void *opaque, int
> n, bool assign)
> * currently only stops on status change away from ok,
> * reset, vmstop and such. If we do add code to start here,
> * need to check vmstate, device state etc. */
> - return virtio_pci_set_host_notifier_internal(proxy, n, assign);
> + return virtio_pci_set_host_notifier_internal(proxy, n, assign, false);
> }
>
> static void virtio_pci_vmstate_change(void *opaque, bool running)
> diff --git a/hw/virtio.c b/hw/virtio.c
> index d146f86..89e6d6f 100644
> --- a/hw/virtio.c
> +++ b/hw/virtio.c
> @@ -1021,13 +1021,16 @@ static void
> virtio_queue_host_notifier_read(EventNotifier *n)
> }
> }
>
> -void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign)
> +void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign,
> + bool set_handler)
> {
> - if (assign) {
> + if (assign && set_handler) {
> event_notifier_set_handler(&vq->host_notifier,
> virtio_queue_host_notifier_read);
> } else {
> event_notifier_set_handler(&vq->host_notifier, NULL);
> + }
> + if (!assign) {
> /* Test and clear notifier before after disabling event,
> * in case poll callback didn't have time to run. */
> virtio_queue_host_notifier_read(&vq->host_notifier);
> diff --git a/hw/virtio.h b/hw/virtio.h
> index f8b5535..d6a8ea3 100644
> --- a/hw/virtio.h
> +++ b/hw/virtio.h
> @@ -233,7 +233,8 @@ EventNotifier *virtio_queue_get_guest_notifier(VirtQueue
> *vq);
> void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
> bool with_irqfd);
> EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq);
> -void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign);
> +void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign,
> + bool set_handler);
> void virtio_queue_notify_vq(VirtQueue *vq);
> void virtio_irq(VirtQueue *vq);
> #endif
> --
> 1.7.11.2
