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| author | Paolo Bonzini <pbonzini@redhat.com> | 2016-12-18 21:43:41 +0100 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2017-01-09 14:48:03 +0100 |
| commit | 4d82d12b39132e820b9ac4aa058ccc733db98917 (patch) | |
| tree | 1b45c6b38d4a934131b77c62f964c36a4676b18f /arch/x86/kvm/lapic.c | |
| parent | KVM: lapic: do not set KVM_REQ_EVENT unnecessarily on PPR update (diff) | |
| download | linux-4d82d12b39132e820b9ac4aa058ccc733db98917.tar.xz linux-4d82d12b39132e820b9ac4aa058ccc733db98917.zip | |
KVM: lapic: do not scan IRR when delivering an interrupt
On interrupt delivery the PPR can only grow (except for auto-EOI),
so it is impossible that non-auto-EOI interrupt delivery results
in KVM_REQ_EVENT. We can therefore use __apic_update_ppr.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/lapic.c')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 457fb206647d..10a745faa659 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2115,6 +2115,7 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu) { int vector = kvm_apic_has_interrupt(vcpu); struct kvm_lapic *apic = vcpu->arch.apic; + u32 ppr; if (vector == -1) return -1; @@ -2126,13 +2127,23 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu) * because the process would deliver it through the IDT. */ - apic_set_isr(vector, apic); - apic_update_ppr(apic); apic_clear_irr(vector, apic); - if (test_bit(vector, vcpu_to_synic(vcpu)->auto_eoi_bitmap)) { - apic_clear_isr(vector, apic); + /* + * For auto-EOI interrupts, there might be another pending + * interrupt above PPR, so check whether to raise another + * KVM_REQ_EVENT. + */ apic_update_ppr(apic); + } else { + /* + * For normal interrupts, PPR has been raised and there cannot + * be a higher-priority pending interrupt---except if there was + * a concurrent interrupt injection, but that would have + * triggered KVM_REQ_EVENT already. + */ + apic_set_isr(vector, apic); + __apic_update_ppr(apic, &ppr); } return vector; |