diff options
Diffstat (limited to 'arch/x86/kvm/lapic.c')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 2098dc689088..95c6beb8ce27 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2629,19 +2629,26 @@ void kvm_apic_update_apicv(struct kvm_vcpu *vcpu) { struct kvm_lapic *apic = vcpu->arch.apic; - if (apic->apicv_active) { - /* irr_pending is always true when apicv is activated. */ - apic->irr_pending = true; + /* + * When APICv is enabled, KVM must always search the IRR for a pending + * IRQ, as other vCPUs and devices can set IRR bits even if the vCPU + * isn't running. If APICv is disabled, KVM _should_ search the IRR + * for a pending IRQ. But KVM currently doesn't ensure *all* hardware, + * e.g. CPUs and IOMMUs, has seen the change in state, i.e. searching + * the IRR at this time could race with IRQ delivery from hardware that + * still sees APICv as being enabled. + * + * FIXME: Ensure other vCPUs and devices observe the change in APICv + * state prior to updating KVM's metadata caches, so that KVM + * can safely search the IRR and set irr_pending accordingly. + */ + apic->irr_pending = true; + + if (apic->apicv_active) apic->isr_count = 1; - } else { - /* - * Don't clear irr_pending, searching the IRR can race with - * updates from the CPU as APICv is still active from hardware's - * perspective. The flag will be cleared as appropriate when - * KVM injects the interrupt. - */ + else apic->isr_count = count_vectors(apic->regs + APIC_ISR); - } + apic->highest_isr_cache = -1; } |