Commit c364baad authored by Sean Christopherson's avatar Sean Christopherson
Browse files

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 <yosry.ahmed@linux.dev>
Link: https://lore.kernel.org/r/20250401161804.842968-2-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 87e4951e

arch/x86/kvm/vmx/posted_intr.c

+3 −4
Original line number Diff line number Diff line
@@ -148,9 +148,8 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) 


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);