[fedora-virt] [PATCH 1/7] msix: migration fix

[Michael S. Tsirkin]

Be careful to match mask/unmask callbacks from msix.
Fixes crash during migration.

Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
 hw/msix.c |   16 +++++++++++++---
 1 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/hw/msix.c b/hw/msix.c
index 31a61c6..97ce301 100644
--- a/hw/msix.c
+++ b/hw/msix.c
@@ -614,9 +614,19 @@ int msix_set_mask_notifier(PCIDevice *dev, unsigned vector, void *opaque)
     if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector])
         return 0;
 
-    if (dev->msix_mask_notifier)
-        r = dev->msix_mask_notifier(dev, vector, opaque,
-                                    msix_is_masked(dev, vector));
+    if (dev->msix_mask_notifier && !msix_is_masked(dev, vector)) {
+        /* Mask previous notifier if any */
+        if (dev->msix_mask_notifier_opaque[vector]) {
+            r = dev->msix_mask_notifier(dev, vector,
+                                        dev->msix_mask_notifier_opaque[vector],
+                                        1);
+            assert(r >= 0);
+        }
+        /* Unmask new notifier, assumed to be masked at start */
+        if (opaque) {
+            r = dev->msix_mask_notifier(dev, vector, opaque, 0);
+        }
+    }
     if (r >= 0)
         dev->msix_mask_notifier_opaque[vector] = opaque;
     return r;
-- 
1.7.0.18.g0d53a5