KVM: Add statistic for remote tlb flushes

Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/kvm.h

@@ -300,6 +300,7 @@ struct kvm_vm_stat {
 	u32 mmu_pde_zapped;
 	u32 mmu_flooded;
 	u32 mmu_recycled;
+	u32 remote_tlb_flush;
 };
 
 struct kvm {

drivers/kvm/kvm_main.c

@@ -115,6 +115,9 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
 		if (cpu != -1 && cpu != raw_smp_processor_id())
 			cpu_set(cpu, cpus);
 	}
+	if (cpus_empty(cpus))
+		return;
+	++kvm->stat.remote_tlb_flush;
 	smp_call_function_mask(cpus, ack_flush, NULL, 1);
 }
 

drivers/kvm/x86.c

@@ -73,6 +73,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "mmu_pde_zapped", VM_STAT(mmu_pde_zapped) },
 	{ "mmu_flooded", VM_STAT(mmu_flooded) },
 	{ "mmu_recycled", VM_STAT(mmu_recycled) },
+	{ "remote_tlb_flush", VM_STAT(remote_tlb_flush) },
 	{ NULL }
 };