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Subject: Re: [PATCH 5/5] kvm: Replace vcpu->swait with rcuwait
To:     Davidlohr Bueso <dave@stgolabs.net>, tglx@linutronix.de
Cc:     peterz@infradead.org, maz@kernel.org, bigeasy@linutronix.de,
        rostedt@goodmis.org, torvalds@linux-foundation.org,
        will@kernel.org, joel@joelfernandes.org,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        Paul Mackerras <paulus@ozlabs.org>,
        kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org,
        Davidlohr Bueso <dbueso@suse.de>
References: <20200424054837.5138-1-dave@stgolabs.net>
 <20200424054837.5138-6-dave@stgolabs.net>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <69af54bb-8632-fbf7-d774-da9a954ff1b7@redhat.com>
Date:   Sat, 25 Apr 2020 12:24:25 +0200
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I'm squashing this in to keep the changes compared to the current code minimal,
and queuing the series.

Thanks,

Paolo

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index bbefa2a7f950..feca3118b17f 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -230,10 +230,10 @@ static bool kvmppc_ipi_thread(int cpu)
 static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu)
 {
 	int cpu;
-	struct rcuwait *wait;
+	struct rcuwait *waitp;
 
-	wait = kvm_arch_vcpu_get_wait(vcpu);
-	if (rcuwait_wake_up(wait))
+	waitp = kvm_arch_vcpu_get_wait(vcpu);
+	if (rcuwait_wake_up(waitp))
 		++vcpu->stat.halt_wakeup;
 
 	cpu = READ_ONCE(vcpu->arch.thread_cpu);
@@ -3814,7 +3814,10 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc)
 		}
 	}
 
+	prepare_to_rcuwait(&vc->wait);
+	set_current_state(TASK_INTERRUPTIBLE);
 	if (kvmppc_vcore_check_block(vc)) {
+		finish_rcuwait(&vc->wait);
 		do_sleep = 0;
 		/* If we polled, count this as a successful poll */
 		if (vc->halt_poll_ns)
@@ -3827,8 +3830,8 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc)
 	vc->vcore_state = VCORE_SLEEPING;
 	trace_kvmppc_vcore_blocked(vc, 0);
 	spin_unlock(&vc->lock);
-	rcuwait_wait_event(&vc->wait,
-			   kvmppc_vcore_check_block(vc), TASK_INTERRUPTIBLE);
+	schedule();
+	finish_rcuwait(&vc->wait);
 	spin_lock(&vc->lock);
 	vc->vcore_state = VCORE_INACTIVE;
 	trace_kvmppc_vcore_blocked(vc, 1);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7c2d18c12d87..c671de51a753 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2737,10 +2737,10 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_block);
 
 bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
 {
-	struct rcuwait *wait;
+	struct rcuwait *waitp;
 
-	wait = kvm_arch_vcpu_get_wait(vcpu);
-	if (rcuwait_wake_up(wait)) {
+	waitp = kvm_arch_vcpu_get_wait(vcpu);
+	if (rcuwait_wake_up(waitp)) {
 		WRITE_ONCE(vcpu->ready, true);
 		++vcpu->stat.halt_wakeup;
 		return true;