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| author | Stefan Hajnoczi <stefanha@redhat.com> | 2018-03-07 14:42:05 +0000 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2018-03-08 17:38:51 +0000 |
| commit | 4486e89c219c0d1b9bd8dfa0b1dd5b0d51ff2268 (patch) | |
| tree | 629e62ffd260635269f0fdcedd392256639c09cc /include | |
| parent | 184b9623461e73ef79f5cebe68bdbcf2e4751e22 (diff) | |
| download | qemu-4486e89c219c0d1b9bd8dfa0b1dd5b0d51ff2268.zip | |
vl: introduce vm_shutdown()
Commit 00d09fdbbae5f7864ce754913efc84c12fdf9f1a ("vl: pause vcpus before
stopping iothreads") and commit dce8921b2baaf95974af8176406881872067adfa
("iothread: Stop threads before main() quits") tried to work around the
fact that emulation was still active during termination by stopping
iothreads. They suffer from race conditions:
1. virtio_scsi_handle_cmd_vq() racing with iothread_stop_all() hits the
virtio_scsi_ctx_check() assertion failure because the BDS AioContext
has been modified by iothread_stop_all().
2. Guest vq kick racing with main loop termination leaves a readable
ioeventfd that is handled by the next aio_poll() when external
clients are enabled again, resulting in unwanted emulation activity.
This patch obsoletes those commits by fully disabling emulation activity
when vcpus are stopped.
Use the new vm_shutdown() function instead of pause_all_vcpus() so that
vm change state handlers are invoked too. Virtio devices will now stop
their ioeventfds, preventing further emulation activity after vm_stop().
Note that vm_stop(RUN_STATE_SHUTDOWN) cannot be used because it emits a
QMP STOP event that may affect existing clients.
It is no longer necessary to call replay_disable_events() directly since
vm_shutdown() does so already.
Drop iothread_stop_all() since it is no longer used.
Cc: Fam Zheng <famz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20180307144205.20619-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/sysemu/iothread.h | 1 | ||||
| -rw-r--r-- | include/sysemu/sysemu.h | 1 |
2 files changed, 1 insertions, 1 deletions
diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h index 799614ffd2..8a7ac2c528 100644 --- a/include/sysemu/iothread.h +++ b/include/sysemu/iothread.h @@ -45,7 +45,6 @@ typedef struct { char *iothread_get_id(IOThread *iothread); IOThread *iothread_by_id(const char *id); AioContext *iothread_get_aio_context(IOThread *iothread); -void iothread_stop_all(void); GMainContext *iothread_get_g_main_context(IOThread *iothread); /* diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h index d24ad09f37..356bfdc1c1 100644 --- a/include/sysemu/sysemu.h +++ b/include/sysemu/sysemu.h @@ -56,6 +56,7 @@ void vm_start(void); int vm_prepare_start(void); int vm_stop(RunState state); int vm_stop_force_state(RunState state); +int vm_shutdown(void); typedef enum WakeupReason { /* Always keep QEMU_WAKEUP_REASON_NONE = 0 */ |