1 files changed, 38 insertions, 22 deletions

diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index bec6c2c66b..032abfbf1a 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -377,27 +377,18 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
     trace_postcopy_ram_incoming_cleanup_entry();
 
     if (mis->have_fault_thread) {
-        uint64_t tmp64;
-
         if (qemu_ram_foreach_block(cleanup_range, mis)) {
             return -1;
         }
-        /*
-         * Tell the fault_thread to exit, it's an eventfd that should
-         * currently be at 0, we're going to increment it to 1
-         */
-        tmp64 = 1;
-        if (write(mis->userfault_quit_fd, &tmp64, 8) == 8) {
-            trace_postcopy_ram_incoming_cleanup_join();
-            qemu_thread_join(&mis->fault_thread);
-        } else {
-            /* Not much we can do here, but may as well report it */
-            error_report("%s: incrementing userfault_quit_fd: %s", __func__,
-                         strerror(errno));
-        }
+        /* Let the fault thread quit */
+        atomic_set(&mis->fault_thread_quit, 1);
+        postcopy_fault_thread_notify(mis);
+        trace_postcopy_ram_incoming_cleanup_join();
+        qemu_thread_join(&mis->fault_thread);
+
         trace_postcopy_ram_incoming_cleanup_closeuf();
         close(mis->userfault_fd);
-        close(mis->userfault_quit_fd);
+        close(mis->userfault_event_fd);
         mis->have_fault_thread = false;
     }
 
@@ -520,7 +511,7 @@ static void *postcopy_ram_fault_thread(void *opaque)
         pfd[0].fd = mis->userfault_fd;
         pfd[0].events = POLLIN;
         pfd[0].revents = 0;
-        pfd[1].fd = mis->userfault_quit_fd;
+        pfd[1].fd = mis->userfault_event_fd;
         pfd[1].events = POLLIN; /* Waiting for eventfd to go positive */
         pfd[1].revents = 0;
 
@@ -530,8 +521,18 @@ static void *postcopy_ram_fault_thread(void *opaque)
         }
 
         if (pfd[1].revents) {
-            trace_postcopy_ram_fault_thread_quit();
-            break;
+            uint64_t tmp64 = 0;
+
+            /* Consume the signal */
+            if (read(mis->userfault_event_fd, &tmp64, 8) != 8) {
+                /* Nothing obviously nicer than posting this error. */
+                error_report("%s: read() failed", __func__);
+            }
+
+            if (atomic_read(&mis->fault_thread_quit)) {
+                trace_postcopy_ram_fault_thread_quit();
+                break;
+            }
         }
 
         ret = read(mis->userfault_fd, &msg, sizeof(msg));
@@ -610,9 +611,9 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis)
     }
 
     /* Now an eventfd we use to tell the fault-thread to quit */
-    mis->userfault_quit_fd = eventfd(0, EFD_CLOEXEC);
-    if (mis->userfault_quit_fd == -1) {
-        error_report("%s: Opening userfault_quit_fd: %s", __func__,
+    mis->userfault_event_fd = eventfd(0, EFD_CLOEXEC);
+    if (mis->userfault_event_fd == -1) {
+        error_report("%s: Opening userfault_event_fd: %s", __func__,
                      strerror(errno));
         close(mis->userfault_fd);
         return -1;
@@ -813,6 +814,21 @@ void *postcopy_get_tmp_page(MigrationIncomingState *mis)
 
 /* ------------------------------------------------------------------------- */
 
+void postcopy_fault_thread_notify(MigrationIncomingState *mis)
+{
+    uint64_t tmp64 = 1;
+
+    /*
+     * Wakeup the fault_thread.  It's an eventfd that should currently
+     * be at 0, we're going to increment it to 1
+     */
+    if (write(mis->userfault_event_fd, &tmp64, 8) != 8) {
+        /* Not much we can do here, but may as well report it */
+        error_report("%s: incrementing failed: %s", __func__,
+                     strerror(errno));
+    }
+}
+
 /**
  * postcopy_discard_send_init: Called at the start of each RAMBlock before
  *   asking to discard individual ranges.