From: Adamos Ttofari Date: Thu, 8 Dec 2022 09:44:14 +0000 (+0000) Subject: KVM: x86: ioapic: Fix level-triggered EOI and userspace I/OAPIC reconfigure race X-Git-Tag: v6.6.7~3413^2~17^2~66 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=fceb3a36c29a957515d5156e5e7844ea040dc43d;p=platform%2Fkernel%2Flinux-starfive.git KVM: x86: ioapic: Fix level-triggered EOI and userspace I/OAPIC reconfigure race 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 Reviewed-by: Sean Christopherson Message-Id: <20221208094415.12723-1-attofari@amazon.de> Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c index 0687162..3742d9a 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); } }