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virtio: fix vhost handling 

Commit b1f416aa8d 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 <stefanha@linux.vnet.ibm.com>
Tested-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Paolo Bonzini 2012-08-06 15:26:14 +02:00 committed by Anthony Liguori
parent 22d48de65c
commit 26b9b5fe17
3 changed files with 14 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
hw/virtio-pci.c
View File

@ -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)

7
hw/virtio.c
View File

@ -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);

3
hw/virtio.h
View File

@ -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