From: Xie Yongji <xieyon...@baidu.com>
Since we now support the message VHOST_USER_GET_INFLIGHT_FD
and VHOST_USER_SET_INFLIGHT_FD. The backend is able to restart
safely because it can track inflight I/O in shared memory.
This patch allows qemu to reconnect the backend after
connection closed.
Signed-off-by: Xie Yongji <xieyon...@baidu.com>
Signed-off-by: Ni Xun <ni...@baidu.com>
Signed-off-by: Zhang Yu <zhangy...@baidu.com>
---
hw/block/vhost-user-blk.c | 205 +++++++++++++++++++++++------
include/hw/virtio/vhost-user-blk.h | 4 +
2 files changed, 168 insertions(+), 41 deletions(-)
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index e1c48b938c..a551486151 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -101,7 +101,7 @@ const VhostDevConfigOps blk_ops = {
.vhost_dev_config_notifier = vhost_user_blk_handle_config_change,
};
-static void vhost_user_blk_start(VirtIODevice *vdev)
+static int vhost_user_blk_start(VirtIODevice *vdev)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
@@ -110,13 +110,13 @@ static void vhost_user_blk_start(VirtIODevice *vdev)
if (!k->set_guest_notifiers) {
error_report("binding does not support guest notifiers");
- return;
+ return -ENOSYS;
}
ret = vhost_dev_enable_notifiers(&s->dev, vdev);
if (ret < 0) {
error_report("Error enabling host notifiers: %d", -ret);
- return;
+ return ret;
}
ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
@@ -147,12 +147,13 @@ static void vhost_user_blk_start(VirtIODevice *vdev)
vhost_virtqueue_mask(&s->dev, vdev, i, false);
}
- return;
+ return ret;
err_guest_notifiers:
k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
err_host_notifiers:
vhost_dev_disable_notifiers(&s->dev, vdev);
+ return ret;
}
static void vhost_user_blk_stop(VirtIODevice *vdev)
@@ -171,7 +172,6 @@ static void vhost_user_blk_stop(VirtIODevice *vdev)
ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
if (ret < 0) {
error_report("vhost guest notifier cleanup failed: %d", ret);
- return;
}
vhost_dev_disable_notifiers(&s->dev, vdev);
@@ -181,21 +181,43 @@ static void vhost_user_blk_set_status(VirtIODevice *vdev,
uint8_t status)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
+ int ret;
if (!vdev->vm_running) {
should_start = false;
}
- if (s->dev.started == should_start) {
+ if (s->should_start == should_start) {
+ return;
+ }
+
+ if (!s->connected || s->dev.started == should_start) {
+ s->should_start = should_start;
return;
}
if (should_start) {
- vhost_user_blk_start(vdev);
+ s->should_start = true;
+ /*
+ * make sure vhost_user_blk_handle_output() ignores fake
+ * guest kick by vhost_dev_enable_notifiers()
+ */
+ barrier();
+ ret = vhost_user_blk_start(vdev);
+ if (ret < 0) {
+ error_report("vhost-user-blk: vhost start failed: %s",
+ strerror(-ret));
+ qemu_chr_fe_disconnect(&s->chardev);
+ }
} else {
vhost_user_blk_stop(vdev);
+ /*
+ * make sure vhost_user_blk_handle_output() ignore fake
+ * guest kick by vhost_dev_disable_notifiers()
+ */
+ barrier();
+ s->should_start = false;
}
-
}
static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
@@ -225,13 +247,22 @@ static uint64_t vhost_user_blk_get_features(VirtIODevice
*vdev,
static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
- int i;
+ int i, ret;
if (!(virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1) &&
!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1))) {
return;
}
+ if (s->should_start) {
+ return;
+ }
+ s->should_start = true;
+
+ if (!s->connected) {
+ return;
+ }
+
if (s->dev.started) {
return;
}
@@ -239,7 +270,13 @@ static void vhost_user_blk_handle_output(VirtIODevice
*vdev, VirtQueue *vq)
/* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
* vhost here instead of waiting for .set_status().
*/
- vhost_user_blk_start(vdev);
+ ret = vhost_user_blk_start(vdev);
+ if (ret < 0) {
+ error_report("vhost-user-blk: vhost start failed: %s",
+ strerror(-ret));
+ qemu_chr_fe_disconnect(&s->chardev);
+ return;
+ }
/* Kick right away to begin processing requests already in vring */
for (i = 0; i < s->dev.nvqs; i++) {
@@ -259,12 +296,105 @@ static void vhost_user_blk_reset(VirtIODevice *vdev)
vhost_dev_reset_inflight(s->inflight);
}
+static int vhost_user_blk_connect(DeviceState *dev)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VHostUserBlk *s = VHOST_USER_BLK(vdev);
+ int ret = 0;
+
+ if (s->connected) {
+ return 0;
+ }
+ s->connected = true;
+
+ s->dev.nvqs = s->num_queues;
+ s->dev.vqs = s->vqs;
+ s->dev.vq_index = 0;
+ s->dev.backend_features = 0;
+
+ vhost_dev_set_config_notifier(&s->dev, &blk_ops);
+
+ ret = vhost_dev_init(&s->dev, s->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
+ if (ret < 0) {
+ error_report("vhost-user-blk: vhost initialization failed: %s",
+ strerror(-ret));
+ return ret;
+ }
+
+ /* restore vhost state */
+ if (s->should_start) {
+ ret = vhost_user_blk_start(vdev);
+ if (ret < 0) {
+ error_report("vhost-user-blk: vhost start failed: %s",
+ strerror(-ret));
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static void vhost_user_blk_disconnect(DeviceState *dev)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VHostUserBlk *s = VHOST_USER_BLK(vdev);
+
+ if (!s->connected) {
+ return;
+ }
+ s->connected = false;
+
+ if (s->dev.started) {
+ vhost_user_blk_stop(vdev);
+ }
+
+ vhost_dev_cleanup(&s->dev);
+}
+
+static gboolean vhost_user_blk_watch(GIOChannel *chan, GIOCondition cond,
+ void *opaque)
+{
+ DeviceState *dev = opaque;
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VHostUserBlk *s = VHOST_USER_BLK(vdev);
+
+ qemu_chr_fe_disconnect(&s->chardev);
+
+ return true;
+}
+
+static void vhost_user_blk_event(void *opaque, int event)
+{
+ DeviceState *dev = opaque;
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VHostUserBlk *s = VHOST_USER_BLK(vdev);
+
+ switch (event) {
+ case CHR_EVENT_OPENED:
+ if (vhost_user_blk_connect(dev) < 0) {
+ qemu_chr_fe_disconnect(&s->chardev);
+ return;
+ }
+ s->watch = qemu_chr_fe_add_watch(&s->chardev, G_IO_HUP,
+ vhost_user_blk_watch, dev);
+ break;
+ case CHR_EVENT_CLOSED:
+ vhost_user_blk_disconnect(dev);
+ if (s->watch) {
+ g_source_remove(s->watch);
+ s->watch = 0;
+ }
+ break;
+ }
+}
+
static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBlk *s = VHOST_USER_BLK(vdev);
VhostUserState *user;
int i, ret;
+ Error *err = NULL;
if (!s->chardev.chr) {
error_setg(errp, "vhost-user-blk: chardev is mandatory");
@@ -299,26 +429,28 @@ static void vhost_user_blk_device_realize(DeviceState
*dev, Error **errp)
}
s->inflight = g_new0(struct vhost_inflight, 1);
-
- s->dev.nvqs = s->num_queues;
- s->dev.vqs = g_new(struct vhost_virtqueue, s->dev.nvqs);
- s->dev.vq_index = 0;
- s->dev.backend_features = 0;
-
- vhost_dev_set_config_notifier(&s->dev, &blk_ops);
-
- ret = vhost_dev_init(&s->dev, s->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
- if (ret < 0) {
- error_setg(errp, "vhost-user-blk: vhost initialization failed: %s",
- strerror(-ret));
- goto virtio_err;
- }
+ s->vqs = g_new(struct vhost_virtqueue, s->num_queues);
+ s->watch = 0;
+ s->should_start = false;
+ s->connected = false;
+
+ qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event,
+ NULL, (void *)dev, NULL, true);
+
+reconnect:
+ do {
+ if (qemu_chr_fe_wait_connected(&s->chardev, &err) < 0) {
+ error_report_err(err);
+ err = NULL;
+ sleep(1);
+ }
+ } while (!s->connected);
ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
- sizeof(struct virtio_blk_config));
+ sizeof(struct virtio_blk_config));
if (ret < 0) {
- error_setg(errp, "vhost-user-blk: get block config failed");
- goto vhost_err;
+ error_report("vhost-user-blk: get block config failed");
+ goto reconnect;
}
if (s->blkcfg.num_queues != s->num_queues) {
@@ -327,22 +459,11 @@ static void vhost_user_blk_device_realize(DeviceState
*dev, Error **errp)
ret = vhost_dev_get_inflight(&s->dev, s->inflight);
if (ret < 0) {
- error_setg(errp, "vhost-user-blk: get inflight failed");
- goto vhost_err;
+ error_report("vhost-user-blk: get inflight failed");
+ goto reconnect;
}
return;
-
-vhost_err:
- vhost_dev_cleanup(&s->dev);
-virtio_err:
- g_free(s->dev.vqs);
- g_free(s->inflight);
- virtio_cleanup(vdev);
-
- vhost_user_cleanup(user);
- g_free(user);
- s->vhost_user = NULL;
}
static void vhost_user_blk_device_unrealize(DeviceState *dev, Error **errp)
@@ -351,9 +472,11 @@ static void vhost_user_blk_device_unrealize(DeviceState
*dev, Error **errp)
VHostUserBlk *s = VHOST_USER_BLK(dev);
vhost_user_blk_set_status(vdev, 0);
+ qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, NULL,
+ NULL, NULL, NULL, false);
vhost_dev_cleanup(&s->dev);
vhost_dev_free_inflight(s->inflight);
- g_free(s->dev.vqs);
+ g_free(s->vqs);
g_free(s->inflight);
virtio_cleanup(vdev);
diff --git a/include/hw/virtio/vhost-user-blk.h
b/include/hw/virtio/vhost-user-blk.h
index 445516604a..4849aa5eb5 100644
--- a/include/hw/virtio/vhost-user-blk.h
+++ b/include/hw/virtio/vhost-user-blk.h
@@ -38,6 +38,10 @@ typedef struct VHostUserBlk {
struct vhost_dev dev;
struct vhost_inflight *inflight;
VhostUserState *vhost_user;
+ struct vhost_virtqueue *vqs;
+ guint watch;
+ bool should_start;
+ bool connected;
} VHostUserBlk;
#endif
--
2.17.1
