From 549240e8e09e063b7ba44c9f8497e8499562a34c Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 13 Jul 2021 09:32:50 -0700 Subject: [PATCH] KVM: x86: Remove defunct BSP "update" in local APIC reset Remove a BSP APIC update in kvm_lapic_reset() that is a glorified and confusing nop. When the code was originally added, kvm_vcpu_is_bsp() queried kvm->arch.bsp_vcpu, i.e. the intent was to set the BSP bit in the BSP vCPU's APIC. But, stuffing the BSP bit at INIT was wrong since the guest can change its BSP(s); this was fixed by commit 58d269d8cccc ("KVM: x86: BSP in MSR_IA32_APICBASE is writable"). In other words, kvm_vcpu_is_bsp() is now purely a reflection of vcpu->arch.apic_base.MSR_IA32_APICBASE_BSP, thus the update will always set the current value and kvm_lapic_set_base() is effectively a nop if the new and old values match. The RESET case, which does need to stuff the BSP for the reset vCPU, is handled by vendor code (though this will soon be moved to common code). No functional change intended. Reviewed-by: Reiji Watanabe Signed-off-by: Sean Christopherson Message-Id: <20210713163324.627647-13-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/lapic.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index add4dd1e3528..a24ce8fe93e5 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2367,9 +2367,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event) apic->highest_isr_cache = -1; update_divide_count(apic); atomic_set(&apic->lapic_timer.pending, 0); - if (kvm_vcpu_is_bsp(vcpu)) - kvm_lapic_set_base(vcpu, - vcpu->arch.apic_base | MSR_IA32_APICBASE_BSP); + vcpu->arch.pv_eoi.msr_val = 0; apic_update_ppr(apic); if (vcpu->arch.apicv_active) { -- GitLab