KVM: PPC: Book3S HV: Counters for passthrough IRQ stats

Add VCPU stat counters to track affinity for passthrough
interrupts.

pthru_all: Counts all passthrough interrupts whose IRQ mappings are
           in the kvmppc_passthru_irq_map structure.
pthru_host: Counts all cached passthrough interrupts that were injected
	    from the host through kvm_set_irq (i.e. not handled in
	    real mode).
pthru_bad_aff: Counts how many cached passthrough interrupts have
               bad affinity (receiving CPU is not running VCPU that is
	       the target of the virtual interrupt in the guest).

Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 89ac1f6..ed30d2e 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -137,6 +137,9 @@
 	u64 ld_slow;
 	u64 st_slow;
 #endif
+	u64 pthru_all;
+	u64 pthru_host;
+	u64 pthru_bad_aff;
 };
 
 enum kvm_exit_types {