linux-kernel - [RFC PATCH 06/22] KVM: x86: INIT may transition from HALTED to RUNNABLE

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Message-ID: <20241121185315.3416855-7-mizhang@google.com>
Date: Thu, 21 Nov 2024 18:52:58 +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 06/22] KVM: x86: INIT may transition from HALTED to RUNNABLE

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

When a halted vCPU is awakened by an INIT signal, 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: 6aef266c6e17 ("kvm hypervisor : Add a hypercall to KVM hypervisor to support pv-ticketlocks")
Signed-off-by: Jim Mattson <jmattson@...gle.com>
---
 arch/x86/kvm/lapic.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 95c6beb8ce279..97aa634505306 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -3372,9 +3372,8 @@ int kvm_apic_accept_events(struct kvm_vcpu *vcpu)
 
 	if (test_and_clear_bit(KVM_APIC_INIT, &apic->pending_events)) {
 		kvm_vcpu_reset(vcpu, true);
-		if (kvm_vcpu_is_bsp(apic->vcpu))
-			vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
-		else
+		kvm_vcpu_make_runnable(vcpu);
+		if (!kvm_vcpu_is_bsp(apic->vcpu))
 			vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED;
 	}
 	if (test_and_clear_bit(KVM_APIC_SIPI, &apic->pending_events)) {
-- 
2.47.0.371.ga323438b13-goog