physmem: add missing memory barrier
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 47143ed..a6efd8e 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -2927,6 +2927,8 @@
qemu_mutex_lock(&map_client_list_lock);
client->bh = bh;
QLIST_INSERT_HEAD(&map_client_list, client, link);
+ /* Write map_client_list before reading in_use. */
+ smp_mb();
if (!qatomic_read(&bounce.in_use)) {
cpu_notify_map_clients_locked();
}
@@ -3116,6 +3118,7 @@
qemu_vfree(bounce.buffer);
bounce.buffer = NULL;
memory_region_unref(bounce.mr);
+ /* Clear in_use before reading map_client_list. */
qatomic_mb_set(&bounce.in_use, false);
cpu_notify_map_clients();
}
