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[Qemu-devel] [PATCH] Revert "virtio: move common ioeventfd handling out
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH] Revert "virtio: move common ioeventfd handling out of virtio-pci" |
Date: |
Fri, 3 Aug 2012 15:58:26 +0100 |
This reverts commit b1f416aa8d870fab71030abc9401cfc77b948e8e.
The above commit 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!
Cc: Paolo Bonzini <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
hw/virtio-pci.c | 36 ++++++++++++++++++++++++++++++++++--
hw/virtio.c | 22 ----------------------
hw/virtio.h | 1 -
3 files changed, 34 insertions(+), 25 deletions(-)
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 3ab9747..34262cb 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -173,18 +173,46 @@ static int
virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,
__func__, r);
return r;
}
- virtio_queue_set_host_notifier_fd_handler(vq, true);
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);
+ /* Handle the race condition where the guest kicked and we deassigned
+ * before we got around to handling the kick.
+ */
+ if (event_notifier_test_and_clear(notifier)) {
+ virtio_queue_notify_vq(vq);
+ }
+
event_notifier_cleanup(notifier);
}
return r;
}
+static void virtio_pci_host_notifier_read(void *opaque)
+{
+ VirtQueue *vq = opaque;
+ EventNotifier *n = virtio_queue_get_host_notifier(vq);
+ if (event_notifier_test_and_clear(n)) {
+ virtio_queue_notify_vq(vq);
+ }
+}
+
+static void virtio_pci_set_host_notifier_fd_handler(VirtIOPCIProxy *proxy,
+ int n, bool assign)
+{
+ VirtQueue *vq = virtio_get_queue(proxy->vdev, n);
+ EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
+ if (assign) {
+ qemu_set_fd_handler(event_notifier_get_fd(notifier),
+ virtio_pci_host_notifier_read, NULL, vq);
+ } else {
+ qemu_set_fd_handler(event_notifier_get_fd(notifier),
+ NULL, NULL, NULL);
+ }
+}
+
static void virtio_pci_start_ioeventfd(VirtIOPCIProxy *proxy)
{
int n, r;
@@ -204,6 +232,8 @@ static void virtio_pci_start_ioeventfd(VirtIOPCIProxy
*proxy)
if (r < 0) {
goto assign_error;
}
+
+ virtio_pci_set_host_notifier_fd_handler(proxy, n, true);
}
proxy->ioeventfd_started = true;
return;
@@ -214,6 +244,7 @@ assign_error:
continue;
}
+ virtio_pci_set_host_notifier_fd_handler(proxy, n, false);
r = virtio_pci_set_host_notifier_internal(proxy, n, false);
assert(r >= 0);
}
@@ -235,6 +266,7 @@ static void virtio_pci_stop_ioeventfd(VirtIOPCIProxy *proxy)
continue;
}
+ virtio_pci_set_host_notifier_fd_handler(proxy, n, false);
r = virtio_pci_set_host_notifier_internal(proxy, n, false);
assert(r >= 0);
}
diff --git a/hw/virtio.c b/hw/virtio.c
index d146f86..1fab9bb 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -1012,28 +1012,6 @@ EventNotifier *virtio_queue_get_guest_notifier(VirtQueue
*vq)
{
return &vq->guest_notifier;
}
-
-static void virtio_queue_host_notifier_read(EventNotifier *n)
-{
- VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
- if (event_notifier_test_and_clear(n)) {
- virtio_queue_notify_vq(vq);
- }
-}
-
-void virtio_queue_set_host_notifier_fd_handler(VirtQueue *vq, bool assign)
-{
- if (assign) {
- event_notifier_set_handler(&vq->host_notifier,
- virtio_queue_host_notifier_read);
- } else {
- event_notifier_set_handler(&vq->host_notifier, NULL);
- /* 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);
- }
-}
-
EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
{
return &vq->host_notifier;
diff --git a/hw/virtio.h b/hw/virtio.h
index f8b5535..6ae5b6e 100644
--- a/hw/virtio.h
+++ b/hw/virtio.h
@@ -233,7 +233,6 @@ 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_notify_vq(VirtQueue *vq);
void virtio_irq(VirtQueue *vq);
#endif
--
1.7.10.4
- [Qemu-devel] [PATCH] Revert "virtio: move common ioeventfd handling out of virtio-pci",
Stefan Hajnoczi <=