Merge remote-tracking branch 'remotes/awilliam/tags/vfio-fixes-20180823.1' into staging

VFIO fixes 2018-08-23

 - Fix coverity reported issue with use of realpath (Alex Williamson)

 - Cleanup file descriptor in error path (Alex Williamson)

 - Fix postcopy use of new balloon inhibitor (Alex Williamson)

# gpg: Signature made Thu 23 Aug 2018 17:46:41 BST
# gpg:                using RSA key 239B9B6E3BB08B22
# gpg: Good signature from "Alex Williamson <alex.williamson@redhat.com>"
# gpg:                 aka "Alex Williamson <alex@shazbot.org>"
# gpg:                 aka "Alex Williamson <alwillia@redhat.com>"
# gpg:                 aka "Alex Williamson <alex.l.williamson@gmail.com>"
# Primary key fingerprint: 42F6 C04E 540B D1A9 9E7B  8A90 239B 9B6E 3BB0 8B22

* remotes/awilliam/tags/vfio-fixes-20180823.1:
  postcopy: Synchronize usage of the balloon inhibitor
  vfio/pci: Fix failure to close file descriptor on error
  vfio/pci: Handle subsystem realpath() returning NULL

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 16 insertions, 2 deletions

diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 3952d78e6b..853d8b32ca 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -510,6 +510,20 @@ int postcopy_ram_incoming_init(MigrationIncomingState *mis)
 }
 
 /*
+ * Manage a single vote to the QEMU balloon inhibitor for all postcopy usage,
+ * last caller wins.
+ */
+static void postcopy_balloon_inhibit(bool state)
+{
+    static bool cur_state = false;
+
+    if (state != cur_state) {
+        qemu_balloon_inhibit(state);
+        cur_state = state;
+    }
+}
+
+/*
  * At the end of a migration where postcopy_ram_incoming_init was called.
  */
 int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
@@ -539,7 +553,7 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
         mis->have_fault_thread = false;
     }
 
-    qemu_balloon_inhibit(false);
+    postcopy_balloon_inhibit(false);
 
     if (enable_mlock) {
         if (os_mlock() < 0) {
@@ -1109,7 +1123,7 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis)
      * Ballooning can mark pages as absent while we're postcopying
      * that would cause false userfaults.
      */
-    qemu_balloon_inhibit(true);
+    postcopy_balloon_inhibit(true);
 
     trace_postcopy_ram_enable_notify();