From c364baad3e4f114284581c35d4b9006d59d2629a Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 1 Apr 2025 09:18:02 -0700 Subject: [PATCH] KVM: VMX: Don't send UNBLOCK when starting device assignment without APICv When starting device assignment, i.e. potential IRQ bypass, don't blast KVM_REQ_UNBLOCK if APICv is disabled/unsupported. There is no need to wake vCPUs if they can never use VT-d posted IRQs (sending UNBLOCK guards against races being vCPUs blocking and devices starting IRQ bypass). Opportunistically use kvm_arch_has_irq_bypass() for all relevant checks in the VMX Posted Interrupt code so that all checks in KVM x86 incorporate the same information (once AMD/AVIC is given similar treatment). Cc: Yosry Ahmed Link: https://lore.kernel.org/r/20250401161804.842968-2-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/posted_intr.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index 99d1d599ff8ce..4cf5bf5b33d71 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -148,9 +148,8 @@ after_clear_sn: static bool vmx_can_use_vtd_pi(struct kvm *kvm) { - return irqchip_in_kernel(kvm) && enable_apicv && - kvm_arch_has_assigned_device(kvm) && - irq_remapping_cap(IRQ_POSTING_CAP); + return irqchip_in_kernel(kvm) && kvm_arch_has_irq_bypass() && + kvm_arch_has_assigned_device(kvm); } /* @@ -281,7 +280,7 @@ bool pi_has_pending_interrupt(struct kvm_vcpu *vcpu) */ void vmx_pi_start_assignment(struct kvm *kvm) { - if (!irq_remapping_cap(IRQ_POSTING_CAP)) + if (!kvm_arch_has_irq_bypass()) return; kvm_make_all_cpus_request(kvm, KVM_REQ_UNBLOCK); -- 2.47.3