Add logic to transfer virtio notifiers through migration channel
for vhost backend migration case.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
---
hw/virtio/virtio-bus.c | 2 +-
hw/virtio/virtio.c | 74 ++++++++++++++++++++++++++++++++++++--
include/hw/virtio/virtio.h | 2 ++
3 files changed, 75 insertions(+), 3 deletions(-)
diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
index c7e3941b1e..c1848144a2 100644
--- a/hw/virtio/virtio-bus.c
+++ b/hw/virtio/virtio-bus.c
@@ -286,7 +286,7 @@ int virtio_bus_set_host_notifier(VirtioBusState *bus, int
n, bool assign)
return -ENOSYS;
}
- if (assign) {
+ if (assign && !virtio_is_vhost_migrating_backend(vdev)) {
r = event_notifier_init(notifier, 1);
if (r < 0) {
error_report("%s: unable to init event notifier: %s (%d)",
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 10891f0e0c..87c243edad 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -26,6 +26,7 @@
#include "hw/virtio/virtio.h"
#include "hw/virtio/vhost.h"
#include "migration/qemu-file-types.h"
+#include "migration/qemu-file.h"
#include "qemu/atomic.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/qdev-properties.h"
@@ -2992,6 +2993,7 @@ int virtio_save(VirtIODevice *vdev, QEMUFile *f)
VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff);
int i;
+ bool migrating_backend = virtio_is_vhost_migrating_backend(vdev);
if (k->save_config) {
k->save_config(qbus->parent, f);
@@ -3025,11 +3027,23 @@ int virtio_save(VirtIODevice *vdev, QEMUFile *f)
*/
qemu_put_be64(f, vdev->vq[i].vring.desc);
qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
+
+ if (migrating_backend) {
+ qemu_file_put_fd(f,
+
event_notifier_get_fd(&vdev->vq[i].host_notifier));
+ qemu_file_put_fd(
+ f, event_notifier_get_fd(&vdev->vq[i].guest_notifier));
+ }
+
if (k->save_queue) {
k->save_queue(qbus->parent, i, f);
}
}
+ if (migrating_backend) {
+ qemu_file_put_fd(f, event_notifier_get_fd(&vdev->config_notifier));
+ }
+
if (vdc->save != NULL) {
vdc->save(vdev, f);
}
@@ -3235,6 +3249,8 @@ virtio_load(VirtIODevice *vdev, QEMUFile *f, int
version_id)
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
+ Error *local_err = NULL;
+ bool migrating_backend = virtio_is_vhost_migrating_backend(vdev);
/*
* We poison the endianness to ensure it does not get used before
@@ -3304,6 +3320,13 @@ virtio_load(VirtIODevice *vdev, QEMUFile *f, int
version_id)
vdev->vq[i].signalled_used_valid = false;
vdev->vq[i].notification = true;
+ if (migrating_backend) {
+ event_notifier_init_fd(&vdev->vq[i].host_notifier,
+ qemu_file_get_fd(f));
+ event_notifier_init_fd(&vdev->vq[i].guest_notifier,
+ qemu_file_get_fd(f));
+ }
+
if (!vdev->vq[i].vring.desc && vdev->vq[i].last_avail_idx) {
error_report("VQ %d address 0x0 "
"inconsistent with Host index 0x%x",
@@ -3317,6 +3340,10 @@ virtio_load(VirtIODevice *vdev, QEMUFile *f, int
version_id)
}
}
+ if (migrating_backend) {
+ event_notifier_init_fd(&vdev->config_notifier , qemu_file_get_fd(f));
+ }
+
virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
if (vdc->load != NULL) {
@@ -3333,6 +3360,19 @@ virtio_load(VirtIODevice *vdev, QEMUFile *f, int
version_id)
}
}
+ if (migrating_backend) {
+ /*
+ * On vhost backend migration, device do load host_features from
+ * migration stream. So update host_features.
+ */
+ vdev->host_features = vdc->get_features(vdev, vdev->host_features,
+ &local_err);
+ if (local_err) {
+ error_report_err(local_err);
+ return -EINVAL;
+ }
+ }
+
/* Subsections */
ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
if (ret) {
@@ -3394,6 +3434,18 @@ virtio_load(VirtIODevice *vdev, QEMUFile *f, int
version_id)
continue;
}
+ if (migrating_backend) {
+ /*
+ * Indices are not synced prior backend migration (as we don't
+ * stop vrings by GET_VRING_BASE). No reason to sync them now,
+ * and do any checks.
+ */
+ vdev->vq[i].used_idx = 0;
+ vdev->vq[i].shadow_avail_idx = 0;
+ vdev->vq[i].inuse = 0;
+ continue;
+ }
+
nheads = vring_avail_idx(&vdev->vq[i]) -
vdev->vq[i].last_avail_idx;
/* Check it isn't doing strange things with descriptor numbers. */
if (nheads > vdev->vq[i].vring.num) {
@@ -3762,8 +3814,9 @@ int virtio_queue_set_guest_notifier(VirtIODevice *vdev,
int n, bool assign,
EventNotifierHandler *read_fn = is_config ?
virtio_config_guest_notifier_read :
virtio_queue_guest_notifier_read;
+ bool migrating_backend = virtio_is_vhost_migrating_backend(vdev);
- if (assign) {
+ if (assign && !migrating_backend) {
int r = event_notifier_init(notifier, 0);
if (r < 0) {
return r;
@@ -3773,7 +3826,7 @@ int virtio_queue_set_guest_notifier(VirtIODevice *vdev,
int n, bool assign,
event_notifier_set_handler(notifier,
(assign && !with_irqfd) ? read_fn : NULL);
- if (!assign) {
+ if (!assign && !migrating_backend) {
/* Test and clear notifier before closing it,*/
/* in case poll callback didn't have time to run. */
read_fn(notifier);
@@ -4392,6 +4445,23 @@ done:
return element;
}
+bool virtio_is_vhost_migrating_backend(VirtIODevice *vdev)
+{
+ VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
+ struct vhost_dev *hdev;
+
+ if (!vdc->get_vhost) {
+ return false;
+ }
+
+ hdev = vdc->get_vhost(vdev);
+ if (!hdev) {
+ return false;
+ }
+
+ return hdev->migrating_backend;
+}
+
static const TypeInfo virtio_device_info = {
.name = TYPE_VIRTIO_DEVICE,
.parent = TYPE_DEVICE,
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 9a4a0a94aa..f94a7e5895 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -238,6 +238,8 @@ struct VirtioDeviceClass {
bool (*skip_vhost_migration_log)(VirtIODevice *vdev);
};
+bool virtio_is_vhost_migrating_backend(VirtIODevice *vdev);
+
void virtio_instance_init_common(Object *proxy_obj, void *data,
size_t vdev_size, const char *vdev_name);
--
2.48.1
