linux-kernel - [RFC PATCH 07/22] KVM: nSVM: Nested #VMEXIT may transition from HALTED to RUNNABLE

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Message-ID: <20241121185315.3416855-8-mizhang@google.com>
Date: Thu, 21 Nov 2024 18:52:59 +0000
From: Mingwei Zhang <mizhang@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	Huang Rui <ray.huang@....com>, "Gautham R. Shenoy" <gautham.shenoy@....com>, 
	Mario Limonciello <mario.limonciello@....com>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Viresh Kumar <viresh.kumar@...aro.org>, 
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>, Len Brown <lenb@...nel.org>
Cc: "H. Peter Anvin" <hpa@...or.com>, Perry Yuan <perry.yuan@....com>, kvm@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, 
	Jim Mattson <jmattson@...gle.com>, Mingwei Zhang <mizhang@...gle.com>
Subject: [RFC PATCH 07/22] KVM: nSVM: Nested #VMEXIT may transition from
 HALTED to RUNNABLE

From: Jim Mattson <jmattson@...gle.com>

When a halted vCPU is awakened by a nested event, it might have been
the target of a previous KVM_HC_KICK_CPU hypercall, in which case
pv_unhalted would be set. This flag should be cleared before the next
HLT instruction, as kvm_vcpu_has_events() would otherwise return true
and prevent the vCPU from entering the halt state.

Use kvm_vcpu_make_runnable() to ensure consistent handling of the
HALTED to RUNNABLE state transition.

Fixes: 38c0b192bd6d ("KVM: SVM: leave halted state on vmexit")
Signed-off-by: Jim Mattson <jmattson@...gle.com>
---
 arch/x86/kvm/svm/nested.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index cf84103ce38b9..49e6cdfeac4da 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -994,7 +994,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 	kvm_clear_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu);
 
 	/* in case we halted in L2 */
-	svm->vcpu.arch.mp_state = KVM_MP_STATE_RUNNABLE;
+	kvm_vcpu_make_runnable(vcpu);
 
 	/* Give the current vmcb to the guest */
 
-- 
2.47.0.371.ga323438b13-goog