On Tue, Jul 12, 2022, Sean Christopherson wrote: > On Fri, Jul 01, 2022, Zhang Jiaming wrote: > --- > arch/x86/kvm/lapic.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index 48740a235dee..ef5417d3ce95 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -830,13 +830,16 @@ static bool kvm_apic_match_physical_addr(struct kvm_lapic *apic, u32 mda) > return mda == kvm_x2apic_id(apic); > > /* > - * Hotplug hack: Make LAPIC in xAPIC mode also accept interrupts as if > - * it were in x2APIC mode. Hotplugged VCPUs start in xAPIC mode and > - * this allows unique addressing of VCPUs with APIC ID over 0xff. > - * The 0xff condition is needed because writable xAPIC ID. Doh, this won't apply on kvm/queue, I unintentionally generated this as a delta on top of your patch. I'll remedy that before testing and officially posting. > + * Hotplug hack: Accept interrupts for vCPUs in xAPIC mode as if they > + * were in x2APIC mode if the target APIC ID can't be encoded as an > + * xAPIC ID. This allows unique addressing of hotplugged vCPUs (which > + * start in xAPIC mode) with an APIC ID that is unaddressable in xAPIC > + * mode. Match the x2APIC ID if and only if the target APIC ID can't > + * be encoded in xAPIC to avoid spurious matches against a vCPU that > + * changed its (addressable) xAPIC ID (which is writable). > */ > - if (kvm_x2apic_id(apic) > 0xff && mda == kvm_x2apic_id(apic)) > - return true; > + if (mda > 0xff) > + return mda == kvm_x2apic_id(apic); > > return mda == kvm_xapic_id(apic); > } > > base-commit: ba0d159dd8844469d4e4defff4985a7b80f956e9 > -- >
