linux-kernel - [PATCH 17/43] KVM: x86: Open code necessary bits of kvm_lapic_set

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Date:   Fri, 23 Apr 2021 17:46:19 -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
Subject: [PATCH 17/43] KVM: x86: Open code necessary bits of
 kvm_lapic_set_base() at vCPU RESET

Stuff vcpu->arch.apic_base and apic->base_address directly during APIC
reset, as opposed to bouncing through kvm_set_apic_base() while fudging
the ENABLE bit during creation to avoid the other, unwanted side effects.

This is a step towards consolidating the APIC RESET logic across x86,
VMX, and SVM.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/lapic.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index b088f6984b37..b1366df46d1d 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2305,7 +2305,6 @@ 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)
@@ -2315,10 +2314,13 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 	hrtimer_cancel(&apic->lapic_timer.timer);
 
 	if (!init_event) {
-		msr_val = APIC_DEFAULT_PHYS_BASE | MSR_IA32_APICBASE_ENABLE;
+		vcpu->arch.apic_base = 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);
+			vcpu->arch.apic_base |= MSR_IA32_APICBASE_BSP;
+
+		apic->base_address = MSR_IA32_APICBASE_ENABLE;
+
 		kvm_apic_set_xapic_id(apic, vcpu->vcpu_id);
 	}
 	kvm_apic_set_version(apic->vcpu);
@@ -2461,11 +2463,6 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu, int timer_advance_ns)
 		lapic_timer_advance_dynamic = false;
 	}
 
-	/*
-	 * APIC is created enabled. This will prevent kvm_lapic_set_base from
-	 * thinking that APIC state has changed.
-	 */
-	vcpu->arch.apic_base = MSR_IA32_APICBASE_ENABLE;
 	static_branch_inc(&apic_sw_disabled.key); /* sw disabled at reset */
 	kvm_iodevice_init(&apic->dev, &apic_mmio_ops);
 
-- 
2.31.1.498.g6c1eba8ee3d-goog