KVM: stats: Add halt_wait_ns stats for all architectures

Add simple stats halt_wait_ns to record the time a VCPU has spent on
waiting for all architectures (not just powerpc).
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Message-Id: <20210802165633.1866976-5-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/powerpc/include/asm/kvm_host.h

@@ -103,7 +103,6 @@ struct kvm_vcpu_stat {
 	u64 emulated_inst_exits;
 	u64 dec_exits;
 	u64 ext_intr_exits;
-	u64 halt_wait_ns;
 	u64 halt_successful_wait;
 	u64 dbell_exits;
 	u64 gdbell_exits;

arch/powerpc/kvm/book3s.c

@@ -69,7 +69,6 @@ const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
 	STATS_DESC_COUNTER(VCPU, emulated_inst_exits),
 	STATS_DESC_COUNTER(VCPU, dec_exits),
 	STATS_DESC_COUNTER(VCPU, ext_intr_exits),
-	STATS_DESC_TIME_NSEC(VCPU, halt_wait_ns),
 	STATS_DESC_COUNTER(VCPU, halt_successful_wait),
 	STATS_DESC_COUNTER(VCPU, dbell_exits),
 	STATS_DESC_COUNTER(VCPU, gdbell_exits),

arch/powerpc/kvm/book3s_hv.c

@@ -4144,7 +4144,7 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc)
 
 	/* Attribute wait time */
 	if (do_sleep) {
-		vc->runner->stat.halt_wait_ns +=
+		vc->runner->stat.generic.halt_wait_ns +=
 			ktime_to_ns(cur) - ktime_to_ns(start_wait);
 		/* Attribute failed poll time */
 		if (vc->halt_poll_ns)

arch/powerpc/kvm/booke.c

@@ -67,7 +67,6 @@ const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
 	STATS_DESC_COUNTER(VCPU, emulated_inst_exits),
 	STATS_DESC_COUNTER(VCPU, dec_exits),
 	STATS_DESC_COUNTER(VCPU, ext_intr_exits),
-	STATS_DESC_TIME_NSEC(VCPU, halt_wait_ns),
 	STATS_DESC_COUNTER(VCPU, halt_successful_wait),
 	STATS_DESC_COUNTER(VCPU, dbell_exits),
 	STATS_DESC_COUNTER(VCPU, gdbell_exits),

include/linux/kvm_host.h

@@ -1452,7 +1452,8 @@ struct _kvm_stats_desc {
 	STATS_DESC_COUNTER(VCPU_GENERIC, halt_poll_invalid),		       \
 	STATS_DESC_COUNTER(VCPU_GENERIC, halt_wakeup),			       \
 	STATS_DESC_TIME_NSEC(VCPU_GENERIC, halt_poll_success_ns),	       \
-	STATS_DESC_TIME_NSEC(VCPU_GENERIC, halt_poll_fail_ns)
+	STATS_DESC_TIME_NSEC(VCPU_GENERIC, halt_poll_fail_ns),		       \
+	STATS_DESC_TIME_NSEC(VCPU_GENERIC, halt_wait_ns)
 
 extern struct dentry *kvm_debugfs_dir;
 

include/linux/kvm_types.h

@@ -87,6 +87,7 @@ struct kvm_vcpu_stat_generic {
 	u64 halt_wakeup;
 	u64 halt_poll_success_ns;
 	u64 halt_poll_fail_ns;
+	u64 halt_wait_ns;
 };
 
 #define KVM_STATS_NAME_SIZE	48

virt/kvm/kvm_main.c

@@ -3241,6 +3241,10 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 	}
 	finish_rcuwait(&vcpu->wait);
 	cur = ktime_get();
+	if (waited) {
+		vcpu->stat.generic.halt_wait_ns +=
+			ktime_to_ns(cur) - ktime_to_ns(poll_end);
+	}
 out:
 	kvm_arch_vcpu_unblocking(vcpu);
 	block_ns = ktime_to_ns(cur) - ktime_to_ns(start);