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[RFC 10/10] vhost: Route host->guest notification through shadow virtque
From: |
Eugenio Pérez |
Subject: |
[RFC 10/10] vhost: Route host->guest notification through shadow virtqueue |
Date: |
Fri, 29 Jan 2021 21:54:15 +0100 |
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
hw/virtio/vhost-shadow-virtqueue.h | 2 ++
hw/virtio/vhost-shadow-virtqueue.c | 55 ++++++++++++++++++++++++++++++
hw/virtio/vhost.c | 5 ++-
3 files changed, 61 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/vhost-shadow-virtqueue.h
b/hw/virtio/vhost-shadow-virtqueue.h
index 466f8ae595..99a4e011fd 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -17,6 +17,8 @@
typedef struct VhostShadowVirtqueue VhostShadowVirtqueue;
+EventNotifier *vhost_shadow_vq_get_call_notifier(VhostShadowVirtqueue *vq);
+
bool vhost_shadow_vq_start_rcu(struct vhost_dev *dev,
VhostShadowVirtqueue *svq);
void vhost_shadow_vq_stop_rcu(struct vhost_dev *dev,
diff --git a/hw/virtio/vhost-shadow-virtqueue.c
b/hw/virtio/vhost-shadow-virtqueue.c
index 908c36c66d..e2e0bfe325 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -53,6 +53,34 @@ static void handle_shadow_vq(VirtIODevice *vdev, VirtQueue
*vq)
vhost_shadow_vring_kick(svq);
}
+static void vhost_handle_call(EventNotifier *n)
+{
+ VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue,
+ call_notifier);
+
+ if (event_notifier_test_and_clear(n)) {
+ unsigned idx = virtio_queue_get_idx(svq->vdev, svq->vq);
+
+ /*
+ * Since QEMU has not add any descriptors, virtqueue code thinks its
+ * not needed to signal used. QEMU shadow virtqueue will take
+ * descriptor forwarding soon, so just invalidate used cache for now.
+ */
+ virtio_queue_invalidate_signalled_used(svq->vdev, idx);
+ virtio_notify_irqfd(svq->vdev, svq->vq);
+ }
+}
+
+/*
+ * Get the vhost call notifier of the shadow vq
+ * @vq Shadow virtqueue
+ */
+EventNotifier *vhost_shadow_vq_get_call_notifier(VhostShadowVirtqueue *vq)
+{
+ return &vq->call_notifier;
+}
+
+
/*
* Start shadow virtqueue operation.
* @dev vhost device
@@ -70,6 +98,10 @@ bool vhost_shadow_vq_start_rcu(struct vhost_dev *dev,
.index = idx,
.fd = event_notifier_get_fd(&svq->kick_notifier),
};
+ struct vhost_vring_file call_file = {
+ .index = idx,
+ .fd = event_notifier_get_fd(&svq->call_notifier),
+ };
int r;
bool ok;
@@ -88,6 +120,12 @@ bool vhost_shadow_vq_start_rcu(struct vhost_dev *dev,
goto err_set_vring_kick;
}
+ r = dev->vhost_ops->vhost_set_vring_call(dev, &call_file);
+ if (r != 0) {
+ error_report("Couldn't set call fd: %s", strerror(errno));
+ goto err_set_vring_call;
+ }
+
event_notifier_set_handler(vq_host_notifier,
virtio_queue_host_notifier_read);
virtio_queue_set_host_notifier_enabled(svq->vq, false);
@@ -95,6 +133,11 @@ bool vhost_shadow_vq_start_rcu(struct vhost_dev *dev,
return true;
+err_set_vring_call:
+ kick_file.fd = event_notifier_get_fd(vq_host_notifier);
+ r = dev->vhost_ops->vhost_set_vring_kick(dev, &kick_file);
+ assert(r == 0);
+
err_set_vring_kick:
k->set_vq_handler(dev->vdev, idx, NULL);
@@ -129,6 +172,17 @@ void vhost_shadow_vq_stop_rcu(struct vhost_dev *dev,
event_notifier_set_handler(vq_host_notifier, NULL);
virtio_queue_set_host_notifier_enabled(svq->vq, true);
k->set_vq_handler(svq->vdev, idx, NULL);
+
+ if (!dev->vqs[idx].notifier_is_masked) {
+ EventNotifier *e = vhost_shadow_vq_get_call_notifier(svq);
+
+ /* Restore vhost call */
+ vhost_virtqueue_mask(dev, svq->vdev, idx, false);
+ if (event_notifier_test_and_clear(e)) {
+ virtio_queue_invalidate_signalled_used(svq->vdev, idx);
+ virtio_notify_irqfd(svq->vdev, svq->vq);
+ }
+ }
}
/*
@@ -159,6 +213,7 @@ VhostShadowVirtqueue *vhost_shadow_vq_new(struct vhost_dev
*dev, int idx)
goto err_init_call_notifier;
}
+ event_notifier_set_handler(&svq->call_notifier, vhost_handle_call);
return g_steal_pointer(&svq);
err_init_call_notifier:
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index bde688f278..5ad0990509 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -984,7 +984,6 @@ static int vhost_sw_live_migration_start(struct vhost_dev
*dev)
int stop_idx = idx;
bool ok = vhost_shadow_vq_start_rcu(dev,
dev->shadow_vqs[idx]);
-
if (!ok) {
while (--stop_idx >= 0) {
vhost_shadow_vq_stop_rcu(dev, dev->shadow_vqs[stop_idx]);
@@ -1610,6 +1609,10 @@ void vhost_virtqueue_mask(struct vhost_dev *hdev,
VirtIODevice *vdev, int n,
if (mask) {
assert(vdev->use_guest_notifier_mask);
file.fd = event_notifier_get_fd(&hdev->vqs[index].masked_notifier);
+ } else if (hdev->sw_lm_enabled) {
+ VhostShadowVirtqueue *svq = hdev->shadow_vqs[n];
+ EventNotifier *e = vhost_shadow_vq_get_call_notifier(svq);
+ file.fd = event_notifier_get_fd(e);
} else {
file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
}
--
2.27.0
- [RFC 00/10] vDPA shadow virtqueue - notifications forwarding, Eugenio Pérez, 2021/01/29
- [RFC 01/10] virtio: Add virtqueue_set_handler, Eugenio Pérez, 2021/01/29
- [RFC 02/10] virtio: Add set_vq_handler, Eugenio Pérez, 2021/01/29
- [RFC 03/10] virtio: Add virtio_queue_get_idx, Eugenio Pérez, 2021/01/29
- [RFC 04/10] virtio: Add virtio_queue_host_notifier_status, Eugenio Pérez, 2021/01/29
- [RFC 05/10] vhost: Add vhost_dev_from_virtio, Eugenio Pérez, 2021/01/29
- [RFC 07/10] vhost: Add VhostShadowVirtqueue, Eugenio Pérez, 2021/01/29
- [RFC 06/10] vhost: Save masked_notifier state, Eugenio Pérez, 2021/01/29
- [RFC 08/10] vhost: Add x-vhost-enable-shadow-vq qmp, Eugenio Pérez, 2021/01/29
- [RFC 10/10] vhost: Route host->guest notification through shadow virtqueue,
Eugenio Pérez <=
- [RFC 09/10] vhost: Route guest->host notification through shadow virtqueue, Eugenio Pérez, 2021/01/29