linux-kernel - [PATCH v2 15/46] KVM: x86: Set BSP bit in reset BSP vCPU's APIC base by default

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Message-Id: <20210713163324.627647-16-seanjc@google.com>
Date:   Tue, 13 Jul 2021 09:32:53 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     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>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Reiji Watanabe <reijiw@...gle.com>
Subject: [PATCH v2 15/46] KVM: x86: Set BSP bit in reset BSP vCPU's APIC base
 by default

Set the BSP bit appropriately during local APIC "reset" instead of
relying on vendor code to clean up at a later point.  This is a step
towards consolidating the local APIC, VMX, and SVM xAPIC initialization
code.

Reviewed-by: Reiji Watanabe <reijiw@...gle.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/lapic.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index acb201d16b5e..0fb282b64c8f 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2321,6 +2321,7 @@ EXPORT_SYMBOL_GPL(kvm_apic_update_apicv);
 void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
+	u64 msr_val;
 	int i;
 
 	if (!apic)
@@ -2330,8 +2331,10 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 	hrtimer_cancel(&apic->lapic_timer.timer);
 
 	if (!init_event) {
-		kvm_lapic_set_base(vcpu, APIC_DEFAULT_PHYS_BASE |
-		                         MSR_IA32_APICBASE_ENABLE);
+		msr_val = APIC_DEFAULT_PHYS_BASE | MSR_IA32_APICBASE_ENABLE;
+		if (kvm_vcpu_is_reset_bsp(vcpu))
+			msr_val |= MSR_IA32_APICBASE_BSP;
+		kvm_lapic_set_base(vcpu, msr_val);
 		kvm_apic_set_xapic_id(apic, vcpu->vcpu_id);
 	}
 	kvm_apic_set_version(apic->vcpu);
-- 
2.32.0.93.g670b81a890-goog