| Message ID | 20221208094415.12723-1-attofari@amazon.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] KVM: x86: ioapic: Fix level-triggered EOI and userspace I/OAPIC reconfigure race | expand |
On Thu, Dec 08, 2022, Adamos Ttofari wrote: > When scanning userspace I/OAPIC entries, intercept EOI for level-triggered > IRQs if the current vCPU has a pending and/or in-service IRQ for the > vector in its local API, even if the vCPU doesn't match the new entry's > destination. This fixes a race between userspace I/OAPIC reconfiguration > and IRQ delivery that results in the vector's bit being left set in the > remote IRR due to the eventual EOI not being forwarded to the userspace > I/OAPIC. > > Commit 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC > reconfigure race") fixed the in-kernel IOAPIC, but not the userspace > IOAPIC configuration, which has a similar race. > > Fixes: 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC reconfigure race") > > Signed-off-by: Adamos Ttofari <attofari@amazon.de> > --- Reviewed-by: Sean Christopherson <seanjc@google.com>
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c index 0687162c4f22..3742d9adacfc 100644 --- a/arch/x86/kvm/irq_comm.c +++ b/arch/x86/kvm/irq_comm.c @@ -426,8 +426,9 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, kvm_set_msi_irq(vcpu->kvm, entry, &irq); if (irq.trig_mode && - kvm_apic_match_dest(vcpu, NULL, APIC_DEST_NOSHORT, - irq.dest_id, irq.dest_mode)) + (kvm_apic_match_dest(vcpu, NULL, APIC_DEST_NOSHORT, + irq.dest_id, irq.dest_mode) || + kvm_apic_pending_eoi(vcpu, irq.vector))) __set_bit(irq.vector, ioapic_handled_vectors); } }
When scanning userspace I/OAPIC entries, intercept EOI for level-triggered IRQs if the current vCPU has a pending and/or in-service IRQ for the vector in its local API, even if the vCPU doesn't match the new entry's destination. This fixes a race between userspace I/OAPIC reconfiguration and IRQ delivery that results in the vector's bit being left set in the remote IRR due to the eventual EOI not being forwarded to the userspace I/OAPIC. Commit 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC reconfigure race") fixed the in-kernel IOAPIC, but not the userspace IOAPIC configuration, which has a similar race. Fixes: 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC reconfigure race") Signed-off-by: Adamos Ttofari <attofari@amazon.de> --- arch/x86/kvm/irq_comm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)