linux-kernel - [PATCH v2 43/59] KVM: SVM: Don't check for assigned device(s) when activating AVIC

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Message-ID: <20250523010004.3240643-44-seanjc@google.com>
Date: Thu, 22 May 2025 17:59:48 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	Joerg Roedel <joro@...tes.org>, David Woodhouse <dwmw2@...radead.org>, 
	Lu Baolu <baolu.lu@...ux.intel.com>
Cc: kvm@...r.kernel.org, iommu@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	Sairaj Kodilkar <sarunkod@....com>, Vasant Hegde <vasant.hegde@....com>, 
	Maxim Levitsky <mlevitsk@...hat.com>, Joao Martins <joao.m.martins@...cle.com>, 
	Francesco Lavra <francescolavra.fl@...il.com>, David Matlack <dmatlack@...gle.com>
Subject: [PATCH v2 43/59] KVM: SVM: Don't check for assigned device(s) when
 activating AVIC

Don't short-circuit IRTE updating when (de)activating AVIC based on the
VM having assigned devices, as nothing prevents AVIC (de)activation from
racing with device (de)assignment.  And from a performance perspective,
bailing early when there is no assigned device doesn't add much, as
ir_list_lock will never be contended if there's no assigned device.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/avic.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index dadd982b03c0..ab7fb8950cc0 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -732,9 +732,6 @@ static int avic_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)
 	struct vcpu_svm *svm = to_svm(vcpu);
 	struct kvm_kernel_irqfd *irqfd;
 
-	if (!kvm_arch_has_assigned_device(vcpu->kvm))
-		return 0;
-
 	/*
 	 * Here, we go through the per-vcpu ir_list to update all existing
 	 * interrupt remapping table entry targeting this vcpu.
-- 
2.49.0.1151.ga128411c76-goog