From: Sean Christopherson seanjc@google.com
commit a58a66afc464d6d2ec294cd3102f36f3652e7ce4 upstream.
Don't inhibit APICv/AVIC due to an xAPIC ID mismatch if the APIC is hardware disabled. The ID cannot be consumed while the APIC is disabled, and the ID is guaranteed to be set back to the vcpu_id when the APIC is hardware enabled (architectural behavior correctly emulated by KVM).
Fixes: 3743c2f02517 ("KVM: x86: inhibit APICv/AVIC on changes to APIC ID or APIC base") Cc: stable@vger.kernel.org Reviewed-by: Maxim Levitsky mlevitsk@redhat.com Signed-off-by: Sean Christopherson seanjc@google.com Message-Id: 20230106011306.85230-6-seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/lapic.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2072,6 +2072,9 @@ static void kvm_lapic_xapic_id_updated(s { struct kvm *kvm = apic->vcpu->kvm;
+ if (!kvm_apic_hw_enabled(apic)) + return; + if (KVM_BUG_ON(apic_x2apic_mode(apic), kvm)) return;