After fixing the handling of POSTED_INTR_WAKEUP_VECTOR for vCPUs with disabled APICv, take care of POSTED_INTR_VECTOR. The IRTE for an assigned device can trigger a POSTED_INTR_VECTOR even if APICv is disabled on the vCPU that receives it. In that case, the interrupt will just cause a vmexit and leave the ON bit set together with the PIR bit corresponding to the interrupt.
Right now, the interrupt would not be delivered until APICv is re-enabled. However, fixing this is just a matter of always doing the PIR->IRR synchronization, even if the vCPU does not have APICv enabled.
This is not a problem for performance, or if anything it is an improvement. static_call_cond will elide the function call if APICv is not present or disabled, or if (as is the case for AMD hardware) it does not require a sync_pir_to_irr callback. And in the common case where kvm_vcpu_apicv_active(vcpu) is true, one fewer check has to be performed.
Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- arch/x86/kvm/x86.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index dcefb1485362..eda86378dcff 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4445,8 +4445,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s) { - if (kvm_vcpu_apicv_active(vcpu)) - static_call(kvm_x86_sync_pir_to_irr)(vcpu); + static_call_cond(kvm_x86_sync_pir_to_irr)(vcpu);
return kvm_apic_get_state(vcpu, s); } @@ -9645,8 +9644,7 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu) if (irqchip_split(vcpu->kvm)) kvm_scan_ioapic_routes(vcpu, vcpu->arch.ioapic_handled_vectors); else { - if (kvm_vcpu_apicv_active(vcpu)) - static_call(kvm_x86_sync_pir_to_irr)(vcpu); + static_call_cond(kvm_x86_sync_pir_to_irr)(vcpu); if (ioapic_in_kernel(vcpu->kvm)) kvm_ioapic_scan_entry(vcpu, vcpu->arch.ioapic_handled_vectors); } @@ -9919,10 +9917,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
/* * This handles the case where a posted interrupt was - * notified with kvm_vcpu_kick. + * notified with kvm_vcpu_kick. Assigned devices can + * use the POSTED_INTR_VECTOR even if APICv is disabled, + * so do it even if !kvm_vcpu_apicv_active(vcpu). */ - if (kvm_lapic_enabled(vcpu) && kvm_vcpu_apicv_active(vcpu)) - static_call(kvm_x86_sync_pir_to_irr)(vcpu); + if (kvm_lapic_enabled(vcpu)) + static_call_cond(kvm_x86_sync_pir_to_irr)(vcpu);
if (kvm_vcpu_exit_request(vcpu)) { vcpu->mode = OUTSIDE_GUEST_MODE;