linux-kernel - [PATCH v2 2/3] KVM: LAPIC: Reset TMCCT during vCPU reset

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Message-Id: <1623050385-100988-2-git-send-email-wanpengli@tencent.com>
Date:   Mon,  7 Jun 2021 00:19:44 -0700
From:   Wanpeng Li <kernellwp@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>
Subject: [PATCH v2 2/3] KVM: LAPIC: Reset TMCCT during vCPU reset

From: Wanpeng Li <wanpengli@...cent.com>

The value of the current counter register after reset is 0 for both 
Intel and AMD, let's do it in kvm, though, the TMCCT is always computed
on-demand and never directly readable.

Reviewed-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
---
v1 -> v2:
 * update patch description

 arch/x86/kvm/lapic.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 6d72d8f..cbfdecd 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2352,6 +2352,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 	kvm_lapic_set_reg(apic, APIC_ICR2, 0);
 	kvm_lapic_set_reg(apic, APIC_TDCR, 0);
 	kvm_lapic_set_reg(apic, APIC_TMICT, 0);
+	kvm_lapic_set_reg(apic, APIC_TMCCT, 0);
 	for (i = 0; i < 8; i++) {
 		kvm_lapic_set_reg(apic, APIC_IRR + 0x10 * i, 0);
 		kvm_lapic_set_reg(apic, APIC_ISR + 0x10 * i, 0);
-- 
2.7.4