From: Didier Pallard <didier.pall...@6wind.com>
Since guest_mask_notifier can not be used in vhost-user mode due
to buffering implied by unix control socket, force
use_mask_notifier on virtio devices of vhost-user interfaces, and
send correct callfd to the guest at vhost start.
Using guest_notifier_mask function in vhost-user case may
break interrupt mask paradigm, because mask/unmask is not
really done when returning from guest_notifier_mask call, instead
message is posted in a unix socket, and processed later.
Add an option boolean flag 'use_mask_notifier' to disable the use
of guest_notifier_mask in virtio pci.
v3 changes:
In respond to Michael S. Tsirkin comments:
- vhost_net.c: removed dependency on virtio-pci.h
- vhost.c: simplified the check for vhost-user backend,
replaced by checking use_mask_notifier; added comment
explaining why vring for vhost-user initialized in
unmasked state;
- cosmetic fixes.
v2 changes:
- a new boolean field is added to all virtio devices instead
of defining a property in some virtio-pci devices.
Signed-off-by: Victor Kaplansky <vict...@redhat.com>
---
include/hw/virtio/virtio.h | 1 +
hw/net/vhost_net.c | 16 ++++++++++++++--
hw/virtio/vhost.c | 13 +++++++++++++
hw/virtio/virtio-pci.c | 14 ++++++++------
hw/virtio/virtio.c | 1 +
5 files changed, 37 insertions(+), 8 deletions(-)
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 108cdb0f..3acbf999 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -90,6 +90,7 @@ struct VirtIODevice
VMChangeStateEntry *vmstate;
char *bus_name;
uint8_t device_endian;
+ bool use_mask_notifier;
QLIST_HEAD(, VirtQueue) *vector_queues;
};
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 3940a04b..8c1ccadb 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -306,13 +306,25 @@ int vhost_net_start(VirtIODevice *dev, NetClientState
*ncs,
}
for (j = 0; j < total_queues; j++) {
+ struct vhost_net *net;
+
r = vhost_net_set_vnet_endian(dev, ncs[j].peer, true);
if (r < 0) {
goto err_endian;
}
- vhost_net_set_vq_index(get_vhost_net(ncs[j].peer), j * 2);
- }
+ net = get_vhost_net(ncs[j].peer);
+ vhost_net_set_vq_index(net, j * 2);
+
+ /* Force use_mask_notifier reset in vhost user case
+ * Must be done before set_guest_notifier call
+ */
+ if (net->nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER) {
+ /* Force virtual device not use mask notifier */
+ dev->use_mask_notifier = false;
+ }
+ }
+
r = k->set_guest_notifiers(qbus->parent, total_queues * 2, true);
if (r < 0) {
error_report("Error binding guest notifier: %d", -r);
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 7dff7554..f8031fae 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -855,8 +855,21 @@ static int vhost_virtqueue_start(struct vhost_dev *dev,
/* Clear and discard previous events if any. */
event_notifier_test_and_clear(&vq->masked_notifier);
+ /* For vhost user we set vring in unmasked state, since by the
+ * default it masked, and guest_notifier_mask is not used anymore.
+ */
+ if (vdev->use_mask_notifier == false) {
+ file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
+ r = dev->vhost_ops->vhost_set_vring_call(dev, &file);
+ if (r) {
+ r = -errno;
+ goto fail_call;
+ }
+ }
+
return 0;
+fail_call:
fail_kick:
fail_alloc:
cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 5494ff4a..64d263ae 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -806,7 +806,7 @@ static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy,
int nvqs)
/* If guest supports masking, set up irqfd now.
* Otherwise, delay until unmasked in the frontend.
*/
- if (k->guest_notifier_mask) {
+ if (vdev->use_mask_notifier && k->guest_notifier_mask) {
ret = kvm_virtio_pci_irqfd_use(proxy, queue_no, vector);
if (ret < 0) {
kvm_virtio_pci_vq_vector_release(proxy, vector);
@@ -822,7 +822,7 @@ undo:
if (vector >= msix_nr_vectors_allocated(dev)) {
continue;
}
- if (k->guest_notifier_mask) {
+ if (vdev->use_mask_notifier && k->guest_notifier_mask) {
kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
}
kvm_virtio_pci_vq_vector_release(proxy, vector);
@@ -849,7 +849,7 @@ static void kvm_virtio_pci_vector_release(VirtIOPCIProxy
*proxy, int nvqs)
/* If guest supports masking, clean up irqfd now.
* Otherwise, it was cleaned when masked in the frontend.
*/
- if (k->guest_notifier_mask) {
+ if (vdev->use_mask_notifier && k->guest_notifier_mask) {
kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
}
kvm_virtio_pci_vq_vector_release(proxy, vector);
@@ -882,7 +882,7 @@ static int virtio_pci_vq_vector_unmask(VirtIOPCIProxy
*proxy,
/* If guest supports masking, irqfd is already setup, unmask it.
* Otherwise, set it up now.
*/
- if (k->guest_notifier_mask) {
+ if (vdev->use_mask_notifier && k->guest_notifier_mask) {
k->guest_notifier_mask(vdev, queue_no, false);
/* Test after unmasking to avoid losing events. */
if (k->guest_notifier_pending &&
@@ -905,7 +905,7 @@ static void virtio_pci_vq_vector_mask(VirtIOPCIProxy *proxy,
/* If guest supports masking, keep irqfd but mask it.
* Otherwise, clean it up now.
*/
- if (k->guest_notifier_mask) {
+ if (vdev->use_mask_notifier && k->guest_notifier_mask) {
k->guest_notifier_mask(vdev, queue_no, true);
} else {
kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
@@ -1022,7 +1022,9 @@ static int virtio_pci_set_guest_notifier(DeviceState *d,
int n, bool assign,
event_notifier_cleanup(notifier);
}
- if (!msix_enabled(&proxy->pci_dev) && vdc->guest_notifier_mask) {
+ if (!msix_enabled(&proxy->pci_dev) &&
+ vdev->use_mask_notifier &&
+ vdc->guest_notifier_mask) {
vdc->guest_notifier_mask(vdev, n, !assign);
}
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 90f25451..c0238b39 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -792,6 +792,7 @@ void virtio_reset(void *opaque)
vdev->queue_sel = 0;
vdev->status = 0;
vdev->isr = 0;
+ vdev->use_mask_notifier = true;
vdev->config_vector = VIRTIO_NO_VECTOR;
virtio_notify_vector(vdev, vdev->config_vector);
--
Victor
