KVM: PPC: Use PACA backed shadow vcpu

We're being horribly racy right now. All the entry and exit code hijacks
random fields from the PACA that could easily be used by different code in
case we get interrupted, for example by a #MC or even page fault.

After discussing this with Ben, we figured it's best to reserve some more
space in the PACA and just shove off some vcpu state to there.

That way we can drastically improve the readability of the code, make it
less racy and less complex.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 1201f62..d615fa8 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -175,10 +175,13 @@
 	ulong gpr[32];
 
 	ulong pc;
-	u32 cr;
 	ulong ctr;
 	ulong lr;
+
+#ifdef CONFIG_BOOKE
 	ulong xer;
+	u32 cr;
+#endif
 
 	ulong msr;
 #ifdef CONFIG_PPC64