linux-kernel - [PATCH v2 8/9] KVM: return if kvm_vcpu_wake

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Message-Id: <20170426203227.12321-9-rkrcmar@redhat.com>
Date:   Wed, 26 Apr 2017 22:32:26 +0200
From:   Radim Krčmář <rkrcmar@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Christoffer Dall <cdall@...aro.org>,
        Andrew Jones <drjones@...hat.com>,
        Marc Zyngier <marc.zyngier@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Cornelia Huck <cornelia.huck@...ibm.com>,
        James Hogan <james.hogan@...tec.com>,
        Paul Mackerras <paulus@...abs.org>
Subject: [PATCH v2 8/9] KVM: return if kvm_vcpu_wake_up() did wake up the VCPU

No need to kick a VCPU that we have just woken up.

Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
---
 include/linux/kvm_host.h |  2 +-
 virt/kvm/kvm_main.c      | 12 ++++++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 955debd82cf2..38cfe372918c 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -698,7 +698,7 @@ void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn);
 void kvm_vcpu_block(struct kvm_vcpu *vcpu);
 void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu);
 void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu);
-void kvm_vcpu_wake_up(struct kvm_vcpu *vcpu);
+bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu);
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
 int kvm_vcpu_yield_to(struct kvm_vcpu *target);
 void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1efb07643035..632f7b3e198c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -183,8 +183,8 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
 		kvm_make_request(req, vcpu);
 		cpu = vcpu->cpu;
 
-		if (!(req & KVM_REQUEST_NO_WAKEUP))
-			kvm_vcpu_wake_up(vcpu);
+		if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
+			continue;
 
 		if (cpus != NULL && cpu != -1 && cpu != me &&
 		      kvm_vcpu_exiting_guest_mode(vcpu) != OUTSIDE_GUEST_MODE)
@@ -2195,7 +2195,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_block);
 
-void kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
+bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
 {
 	struct swait_queue_head *wqp;
 
@@ -2203,8 +2203,10 @@ void kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
 	if (swait_active(wqp)) {
 		swake_up(wqp);
 		++vcpu->stat.halt_wakeup;
+		return true;
 	}
 
+	return false;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_wake_up);
 
@@ -2216,7 +2218,9 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 	int me;
 	int cpu = vcpu->cpu;
 
-	kvm_vcpu_wake_up(vcpu);
+	if (kvm_vcpu_wake_up(vcpu))
+		return;
+
 	me = get_cpu();
 	if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
 		if (kvm_arch_vcpu_should_kick(vcpu))
-- 
2.12.2