On Wed, 2022-05-04 at 02:31 -0500, Suravee Suthikulpanit wrote: > When launching a VM with x2APIC and specify more than 255 vCPUs, > the guest kernel can disable x2APIC (e.g. specify nox2apic kernel option). > The VM fallbacks to xAPIC mode, and disable the vCPU ID 255 and greater. > > In this case, APICV should be deactivated for the disabled vCPUs. > However, the current APICv consistency warning does not account for > this case, which results in a warning. > > Therefore, modify warning logic to report only when vCPU APIC mode > is valid. > > Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx> > --- > arch/x86/kvm/x86.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 8ee8c91fa762..b14e02ea0ff6 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -9838,6 +9838,10 @@ void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu) > > activate = kvm_vcpu_apicv_activated(vcpu); > > + /* Do not activate AVIC when APIC is disabled */ > + if (kvm_get_apic_mode(vcpu) == LAPIC_MODE_DISABLED) > + activate = false; > + > if (vcpu->arch.apicv_active == activate) > goto out; > > @@ -10240,7 +10244,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) > * per-VM state, and responsing vCPUs must wait for the update > * to complete before servicing KVM_REQ_APICV_UPDATE. > */ > - WARN_ON_ONCE(kvm_vcpu_apicv_activated(vcpu) != kvm_vcpu_apicv_active(vcpu)); > + if (kvm_vcpu_apicv_activated(vcpu) != kvm_vcpu_apicv_active(vcpu)) > + WARN_ON_ONCE(kvm_get_apic_mode(vcpu) != LAPIC_MODE_DISABLED); > > exit_fastpath = static_call(kvm_x86_vcpu_run)(vcpu); > if (likely(exit_fastpath != EXIT_FASTPATH_REENTER_GUEST)) Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> Best regards, Maxim Levitsky
