[PATCH v3 54/62] KVM: VMX: WARN if VT-d Posted IRQs aren't possible when starting IRQ bypass
From: Sean Christopherson <seanjc@google.com>
Date: 2025-06-11 22:48:29
Also in:
kvm, kvmarm, linux-iommu, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
WARN if KVM attempts to "start" IRQ bypass when VT-d Posted IRQs are disabled, to make it obvious that the logic is a sanity check, and so that a bug related to nr_possible_bypass_irqs is more like to cause noisy failures, e.g. so that KVM doesn't silently fail to wake blocking vCPUs. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/vmx/posted_intr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c
index 5671d59a6b6d..4a6d9a17da23 100644
--- a/arch/x86/kvm/vmx/posted_intr.c
+++ b/arch/x86/kvm/vmx/posted_intr.c@@ -296,7 +296,7 @@ bool pi_has_pending_interrupt(struct kvm_vcpu *vcpu) */ void vmx_pi_start_bypass(struct kvm *kvm) { - if (!kvm_arch_has_irq_bypass()) + if (WARN_ON_ONCE(!vmx_can_use_vtd_pi(kvm))) return; kvm_make_all_cpus_request(kvm, KVM_REQ_UNBLOCK);
--
2.50.0.rc1.591.g9c95f17f64-goog