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authorStefan Hajnoczi <stefanha@redhat.com>2018-03-07 14:42:05 +0000
committerStefan Hajnoczi <stefanha@redhat.com>2018-03-08 17:38:51 +0000
commit4486e89c219c0d1b9bd8dfa0b1dd5b0d51ff2268 (patch)
tree629e62ffd260635269f0fdcedd392256639c09cc /include/sysemu/iothread.h
parent184b9623461e73ef79f5cebe68bdbcf2e4751e22 (diff)
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/sysemu/iothread.h')
-rw-r--r--include/sysemu/iothread.h1
1 files changed, 0 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);
/*