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author | Dima Stepanov <dimastep@yandex-team.ru> | 2020-05-28 12:11:19 +0300 |
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committer | Michael S. Tsirkin <mst@redhat.com> | 2020-06-09 14:18:04 -0400 |
commit | 4bcad76f4c390f798198a9a93fbaa1a20d06b73e (patch) | |
tree | 301dbda624ee6b8e1f81091c0b3ce54f1395391e /hw/block | |
parent | 271094474b65de1ad7aaf729938de3d9b9d0d36f (diff) | |
download | qemu-4bcad76f4c390f798198a9a93fbaa1a20d06b73e.zip qemu-4bcad76f4c390f798198a9a93fbaa1a20d06b73e.tar.gz qemu-4bcad76f4c390f798198a9a93fbaa1a20d06b73e.tar.bz2 |
vhost-user-blk: delay vhost_user_blk_disconnect
A socket write during vhost-user communication may trigger a disconnect
event, calling vhost_user_blk_disconnect() and clearing all the
vhost_dev structures holding data that vhost-user functions expect to
remain valid to roll back initialization correctly. Delay the cleanup to
keep vhost_dev structure valid.
There are two possible states to handle:
1. RUN_STATE_PRELAUNCH: skip bh oneshot call and perform disconnect in
the caller routine.
2. RUN_STATE_RUNNING: delay by using bh
BH changes are based on the similar changes for the vhost-user-net
device:
commit e7c83a885f865128ae3cf1946f8cb538b63cbfba
"vhost-user: delay vhost_user_stop"
Signed-off-by: Dima Stepanov <dimastep@yandex-team.ru>
Message-Id: <69b73b94dcd066065595266c852810e0863a0895.1590396396.git.dimastep@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Li Feng <fengli@smartx.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Diffstat (limited to 'hw/block')
-rw-r--r-- | hw/block/vhost-user-blk.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c index 9d8c0b3..76838e7 100644 --- a/hw/block/vhost-user-blk.c +++ b/hw/block/vhost-user-blk.c @@ -349,6 +349,19 @@ static void vhost_user_blk_disconnect(DeviceState *dev) vhost_dev_cleanup(&s->dev); } +static void vhost_user_blk_event(void *opaque, QEMUChrEvent event); + +static void vhost_user_blk_chr_closed_bh(void *opaque) +{ + DeviceState *dev = opaque; + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserBlk *s = VHOST_USER_BLK(vdev); + + vhost_user_blk_disconnect(dev); + qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event, + NULL, opaque, NULL, true); +} + static void vhost_user_blk_event(void *opaque, QEMUChrEvent event) { DeviceState *dev = opaque; @@ -363,7 +376,30 @@ static void vhost_user_blk_event(void *opaque, QEMUChrEvent event) } break; case CHR_EVENT_CLOSED: - vhost_user_blk_disconnect(dev); + /* + * A close event may happen during a read/write, but vhost + * code assumes the vhost_dev remains setup, so delay the + * stop & clear. There are two possible paths to hit this + * disconnect event: + * 1. When VM is in the RUN_STATE_PRELAUNCH state. The + * vhost_user_blk_device_realize() is a caller. + * 2. In tha main loop phase after VM start. + * + * For p2 the disconnect event will be delayed. We can't + * do the same for p1, because we are not running the loop + * at this moment. So just skip this step and perform + * disconnect in the caller function. + * + * TODO: maybe it is a good idea to make the same fix + * for other vhost-user devices. + */ + if (runstate_is_running()) { + AioContext *ctx = qemu_get_current_aio_context(); + + qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, NULL, NULL, + NULL, NULL, false); + aio_bh_schedule_oneshot(ctx, vhost_user_blk_chr_closed_bh, opaque); + } break; case CHR_EVENT_BREAK: case CHR_EVENT_MUX_IN: |