accel: use atomic accesses for exit_request

CPU threads write exit_request as a "note to self" that they need to
go out to a slow path.  This write happens out of the BQL and can be
a data race with another threads' cpu_exit(); use atomic accesses
consistently.

While at it, change the source argument from int ("1") to bool ("true").

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/accel/tcg/tcg-accel-ops-rr.c b/accel/tcg/tcg-accel-ops-rr.c
index e8b0e370a8..d13e0d8b44 100644
--- a/accel/tcg/tcg-accel-ops-rr.c
+++ b/accel/tcg/tcg-accel-ops-rr.c
@@ -212,7 +212,7 @@ static void *rr_cpu_thread_fn(void *arg)
     cpu = first_cpu;
 
     /* process any pending work */
-    cpu->exit_request = 1;
+    qatomic_set(&cpu->exit_request, true);
 
     while (1) {
         /* Only used for icount_enabled() */
@@ -293,7 +293,7 @@ static void *rr_cpu_thread_fn(void *arg)
         /* Does not need a memory barrier because a spurious wakeup is okay.  */
         qatomic_set(&rr_current_cpu, NULL);
 
-        if (cpu && cpu->exit_request) {
+        if (cpu && qatomic_read(&cpu->exit_request)) {
             qatomic_set_mb(&cpu->exit_request, 0);
         }