[2/2] testbot/VMs: Shut down VMs before reverting them.

[Francois Gouget]

This is a workaround for a bug in some QEmu/KVM versions.
---

Specifically QEmu 1.6.0 complains about hardware incompatibility when 
trying to revert a running VM to a running snapshot, which makes 
absolutely no sense.

snapshot-revert fgtbwinxp wtb-sp2
error: revert requires force: Target device address type none does not match source pci

But forcibly shutting down the VM is fast (seconds) and then lets us do 
the revert.

 testbot/bin/RevertVM.pl        | 11 +++++++++++
 testbot/lib/WineTestBot/VMs.pm |  7 ++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/testbot/bin/RevertVM.pl b/testbot/bin/RevertVM.pl
index a253e76..01bcc08 100755
--- a/testbot/bin/RevertVM.pl
+++ b/testbot/bin/RevertVM.pl
@@ -98,6 +98,17 @@ if (defined($ErrMessage))
   FatalError "Can't change status for VM $VMKey: $ErrMessage", $VM;
 }
 
+if ($VM->IsPoweredOn())
+{
+  # Some QEmu/KVM versions are buggy and cannot revert a running VM
+  $ErrMessage = $VM->PowerOff(1);
+  if (defined $ErrMessage)
+  {
+    LogMsg "Could not shut down $VMKey: $ErrMessage\n";
+    LogMsg "Trying the revert anyway\n";
+  }
+}
+
 $ErrMessage = $VM->RevertToSnapshot($VM->IdleSnapshot);
 if (defined($ErrMessage))
 {
diff --git a/testbot/lib/WineTestBot/VMs.pm b/testbot/lib/WineTestBot/VMs.pm
index 3fcb644..9646048 100644
--- a/testbot/lib/WineTestBot/VMs.pm
+++ b/testbot/lib/WineTestBot/VMs.pm
@@ -368,9 +368,9 @@ sub PowerOn
   return $self->UpdateStatus($Domain);
 }
 
-sub PowerOff
+sub PowerOff($$)
 {
-  my ($self) = @_;
+  my ($self, $NoStatus) = @_;
 
   my ($ErrMessage, $Domain) = $self->_GetDomain();
   return $ErrMessage if (defined $ErrMessage);
@@ -378,7 +378,8 @@ sub PowerOff
   eval { $Domain->destroy() };
   return $@->message() if ($@);
 
-  return $self->UpdateStatus($Domain);
+  return $self->UpdateStatus($Domain) if (!$NoStatus);
+  return undef;
 }
 
 sub GetAgent($)
-- 
1.8.4.rc3