KVM: Add fpu_reload counter

Measure the number of times we switch the fpu state.
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/kvm.h

@@ -248,6 +248,7 @@ struct kvm_stat {
 	u32 irq_exits;
 	u32 host_state_reload;
 	u32 efer_reload;
+	u32 fpu_reload;
 };
 
 struct kvm_io_device {

drivers/kvm/x86.c

@@ -62,6 +62,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "irq_exits", STAT_OFFSET(irq_exits) },
 	{ "host_state_reload", STAT_OFFSET(host_state_reload) },
 	{ "efer_reload", STAT_OFFSET(efer_reload) },
+	{ "fpu_reload", STAT_OFFSET(fpu_reload) },
 	{ NULL }
 };
 
@@ -2417,6 +2418,7 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
 	vcpu->guest_fpu_loaded = 0;
 	fx_save(&vcpu->guest_fx_image);
 	fx_restore(&vcpu->host_fx_image);
+	++vcpu->stat.fpu_reload;
 }
 EXPORT_SYMBOL_GPL(kvm_put_guest_fpu);