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| -rw-r--r-- | cpu-exec.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/cpu-exec.c b/cpu-exec.c index e74e55656a..aa8fa893d9 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -217,6 +217,14 @@ int cpu_exec(CPUArchState *env) cpu_single_env = env; + /* As long as cpu_single_env is null, up to the assignment just above, + * requests by other threads to exit the execution loop are expected to + * be issued using the exit_request global. We must make sure that our + * evaluation of the global value is performed past the cpu_single_env + * value transition point, which requires a memory barrier as well as + * an instruction scheduling constraint on modern architectures. */ + smp_mb(); + if (unlikely(exit_request)) { cpu->exit_request = 1; } |