From: Xie Yongji Date: Wed, 20 Mar 2019 11:26:45 +0000 (+0800) Subject: vhost-user-blk: Add support to reconnect backend X-Git-Tag: v4.1.0~157^2~25 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=77542d431491788d1e8e79d93ce10172ef207775;p=mirror_qemu.git vhost-user-blk: Add support to reconnect backend 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 Signed-off-by: Ni Xun Signed-off-by: Zhang Yu Message-Id: <20190320112646.3712-7-xieyongji@baidu.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c index 6802c19d65..9cb61336a6 100644 --- a/hw/block/vhost-user-blk.c +++ b/hw/block/vhost-user-blk.c @@ -192,17 +192,27 @@ static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status) { VHostUserBlk *s = VHOST_USER_BLK(vdev); bool should_start = vdev->started; + int ret; if (!vdev->vm_running) { should_start = false; } + if (!s->connected) { + return; + } + if (s->dev.started == should_start) { return; } if (should_start) { - 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); + } } else { vhost_user_blk_stop(vdev); } @@ -238,12 +248,16 @@ 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 (!vdev->start_on_kick) { return; } + if (!s->connected) { + return; + } + if (s->dev.started) { return; } @@ -251,7 +265,13 @@ 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++) { @@ -271,11 +291,103 @@ static void vhost_user_blk_reset(VirtIODevice *vdev) vhost_dev_free_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 (vdev->started) { + 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); - struct vhost_virtqueue *vqs = NULL; + Error *err = NULL; int i, ret; if (!s->chardev.chr) { @@ -306,27 +418,29 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp) } s->inflight = g_new0(struct vhost_inflight, 1); + s->vqs = g_new(struct vhost_virtqueue, s->num_queues); + s->watch = 0; + s->connected = false; - 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; - vqs = s->dev.vqs; - - vhost_dev_set_config_notifier(&s->dev, &blk_ops); + qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event, + NULL, (void *)dev, NULL, true); - 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)); +reconnect: + if (qemu_chr_fe_wait_connected(&s->chardev, &err) < 0) { + error_report_err(err); goto virtio_err; } + /* check whether vhost_user_blk_connect() failed or not */ + if (!s->connected) { + goto reconnect; + } + 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) { @@ -335,10 +449,8 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp) return; -vhost_err: - vhost_dev_cleanup(&s->dev); virtio_err: - g_free(vqs); + g_free(s->vqs); g_free(s->inflight); virtio_cleanup(vdev); vhost_user_cleanup(&s->vhost_user); @@ -348,12 +460,13 @@ static void vhost_user_blk_device_unrealize(DeviceState *dev, Error **errp) { VirtIODevice *vdev = VIRTIO_DEVICE(dev); VHostUserBlk *s = VHOST_USER_BLK(dev); - struct vhost_virtqueue *vqs = s->dev.vqs; virtio_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(vqs); + g_free(s->vqs); g_free(s->inflight); virtio_cleanup(vdev); vhost_user_cleanup(&s->vhost_user); diff --git a/include/hw/virtio/vhost-user-blk.h b/include/hw/virtio/vhost-user-blk.h index 68634bee61..51457fb857 100644 --- a/include/hw/virtio/vhost-user-blk.h +++ b/include/hw/virtio/vhost-user-blk.h @@ -38,6 +38,9 @@ typedef struct VHostUserBlk { struct vhost_dev dev; struct vhost_inflight *inflight; VhostUserState vhost_user; + struct vhost_virtqueue *vqs; + guint watch; + bool connected; } VHostUserBlk; #endif