[PATCH] Fix bugs in msix_set/unset_mask_notifier() routines

[Sridhar Samudrala <sri@us.ibm.com>]

I am hitting the following assertions in msix.c when doing a guest reboot or live migration
using vhost.
qemu-kvm/hw/msix.c:375: msix_mask_all: Assertion `r >= 0' failed.
qemu-kvm/hw/msix.c:640: msix_unset_mask_notifier: Assertion `dev->msix_mask_notifier_opaque[vector]' failed.

The following patch fixes the bugs in handling msix_is_masked() condition
in msix_set/unset_mask_notifier() routines.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>


diff --git a/hw/msix.c b/hw/msix.c
index 1398680..a191df1 100644
--- a/hw/msix.c
+++ b/hw/msix.c
@@ -609,7 +609,7 @@ void msix_unuse_all_vectors(PCIDevice *dev)
 
 int msix_set_mask_notifier(PCIDevice *dev, unsigned vector, void *opaque)
 {
-    int r;
+    int r = 0;
     if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector])
         return 0;
 
@@ -619,13 +619,15 @@ int msix_set_mask_notifier(PCIDevice *dev, unsigned vector, void *opaque)
 
     /* Unmask the new notifier unless vector is masked. */
     if (msix_is_masked(dev, vector)) {
-        return 0;
+        goto out;
     }
     r = dev->msix_mask_notifier(dev, vector, opaque,
                                 msix_is_masked(dev, vector));
     if (r < 0) {
         return r;
     }
+
+out:
     dev->msix_mask_notifier_opaque[vector] = opaque;
     return r;
 }
@@ -640,8 +642,8 @@ int msix_unset_mask_notifier(PCIDevice *dev, unsigned vector)
     assert(dev->msix_mask_notifier_opaque[vector]);
 
     /* Mask the old notifier unless it is already masked. */
-    if (msix_is_masked(dev, vector)) {
-        return 0;
+    if (!msix_is_masked(dev, vector)) {
+        goto out;
     }
     r = dev->msix_mask_notifier(dev, vector,
                                 dev->msix_mask_notifier_opaque[vector],
@@ -649,6 +651,8 @@ int msix_unset_mask_notifier(PCIDevice *dev, unsigned vector)
     if (r < 0) {
         return r;
     }
+
+out:
     dev->msix_mask_notifier_opaque[vector] = NULL;
     return r;
 }