On Wed, 2022-08-31 at 09:07 +0300, Maxim Levitsky wrote: > On Wed, 2022-08-31 at 00:35 +0000, Sean Christopherson wrote: > > Turns out that some warnings exist for good reasons. Restore the warning > > in avic_vcpu_load() that guards against calling avic_vcpu_load() on a > > running vCPU now that KVM avoids doing so when switching between x2APIC > > and xAPIC. The entire point of the WARN is to highlight that KVM should > > not be reloading an AVIC. > > > > Opportunistically convert the WARN_ON() to WARN_ON_ONCE() to avoid > > spamming the kernel if it does fire. > > > > This reverts commit c0caeee65af3944b7b8abbf566e7cc1fae15c775. > > > > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> > > --- > > arch/x86/kvm/svm/avic.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c > > index b2033a56010c..3c300113d40b 100644 > > --- a/arch/x86/kvm/svm/avic.c > > +++ b/arch/x86/kvm/svm/avic.c > > @@ -1080,6 +1080,7 @@ void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu) > > return; > > > > entry = READ_ONCE(*(svm->avic_physical_id_cache)); > > + WARN_ON_ONCE(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK); > > > > entry &= ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK; > > entry |= (h_physical_id & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK); > > Note that this warning was removed because it would trigger wheh x2avic code would switch > between xapic and x2apic. > > I do agree 100% that this warning is useful. Ah I see that you fixed the apic reloading to not trigger this code, need more coffee - in this case this patch makes lot of sense. I'll review it again when I review rest of the patches in the patch series. Best regards, Maxim Levitsky > > Best regards, > Maxim Levitsky
