From f3ced000a2df53f4b12849e121769045a81a3b22 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 10 Jun 2024 18:48:45 -0700 Subject: KVM: x86: Always sync PIR to IRR prior to scanning I/O APIC routes Sync pending posted interrupts to the IRR prior to re-scanning I/O APIC routes, irrespective of whether the I/O APIC is emulated by userspace or by KVM. If a level-triggered interrupt routed through the I/O APIC is pending or in-service for a vCPU, KVM needs to intercept EOIs on said vCPU even if the vCPU isn't the destination for the new routing, e.g. if servicing an interrupt using the old routing races with I/O APIC reconfiguration. Commit fceb3a36c29a ("KVM: x86: ioapic: Fix level-triggered EOI and userspace I/OAPIC reconfigure race") fixed the common cases, but kvm_apic_pending_eoi() only checks if an interrupt is in the local APIC's IRR or ISR, i.e. misses the uncommon case where an interrupt is pending in the PIR. Failure to intercept EOI can manifest as guest hangs with Windows 11 if the guest uses the RTC as its timekeeping source, e.g. if the VMM doesn't expose a more modern form of time to the guest. Cc: stable@vger.kernel.org Cc: Adamos Ttofari Cc: Raghavendra Rao Ananta Reviewed-by: Jim Mattson Signed-off-by: Sean Christopherson Message-ID: <20240611014845.82795-1-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'arch') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8c9e4281d978..0763a0f72a06 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10718,13 +10718,12 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu) bitmap_zero(vcpu->arch.ioapic_handled_vectors, 256); + static_call_cond(kvm_x86_sync_pir_to_irr)(vcpu); + if (irqchip_split(vcpu->kvm)) kvm_scan_ioapic_routes(vcpu, vcpu->arch.ioapic_handled_vectors); - else { - 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); - } + else if (ioapic_in_kernel(vcpu->kvm)) + kvm_ioapic_scan_entry(vcpu, vcpu->arch.ioapic_handled_vectors); if (is_guest_mode(vcpu)) vcpu->arch.load_eoi_exitmap_pending = true; -- cgit v1.2.3-70-g09d2