linux-kernel - [PATCH 19/23] KVM: SVM: Skip intercepted PAUSE instructions after emulation

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Message-Id: <20210302193343.313318-20-pbonzini@redhat.com>
Date:   Tue,  2 Mar 2021 14:33:39 -0500
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com
Subject: [PATCH 19/23] KVM: SVM: Skip intercepted PAUSE instructions after emulation

From: Sean Christopherson <seanjc@...gle.com>

Skip PAUSE after interception to avoid unnecessarily re-executing the
instruction in the guest, e.g. after regaining control post-yield.
This is a benign bug as KVM disables PAUSE interception if filtering is
off, including the case where pause_filter_count is set to zero.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Message-Id: <20210205005750.3841462-10-seanjc@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm/svm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 3725a4636930..1c62d3ec7e53 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2982,7 +2982,7 @@ static int pause_interception(struct kvm_vcpu *vcpu)
 		grow_ple_window(vcpu);
 
 	kvm_vcpu_on_spin(vcpu, in_kernel);
-	return 1;
+	return kvm_skip_emulated_instruction(vcpu);
 }
 
 static int invpcid_interception(struct kvm_vcpu *vcpu)
-- 
2.26.2