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AJvYcCXw1twrtoO52IopAlMBmWupvqkMevpnGClwyYzR2sfRAigQWSUm/4edXOCHg7VjMsmpBlkP6w==@lists.linux.dev X-Gm-Message-State: AOJu0YwlComMrX3VLZdvFw/nLbA0DM/MZzfY9hYrKQ4+ylpVGsR3iEYM D15jZrYwesyLrEuuGEn07lU8o2qmyTlP4xs2c5S7Hbg1oDQ6MCd5aiR8jHFuUvKEbP5+u0Q6PTF MDutPcQ== X-Google-Smtp-Source: AGHT+IHRskctku8TAbxqTc5JSLZa7cBf4pJ0pj9pJzlkOC6dQa0UxJjlReXD4jK1iH3OFzYeZWUC+JH7b6A= X-Received: from pfaq8.prod.google.com ([2002:a05:6a00:a888:b0:742:a83f:bc0f]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:198e:b0:740:91e4:8107 with SMTP id d2e1a72fcca58-742a963242bmr38441580b3a.0.1747962097793; Thu, 22 May 2025 18:01:37 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 22 May 2025 17:59:57 -0700 In-Reply-To: <20250523010004.3240643-1-seanjc@google.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250523010004.3240643-1-seanjc@google.com> X-Mailer: git-send-email 2.49.0.1151.ga128411c76-goog Message-ID: <20250523010004.3240643-53-seanjc@google.com> Subject: [PATCH v2 52/59] KVM: VMX: WARN if VT-d Posted IRQs aren't possible when starting IRQ bypass From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , Joerg Roedel , David Woodhouse , Lu Baolu Cc: kvm@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Sairaj Kodilkar , Vasant Hegde , Maxim Levitsky , Joao Martins , Francesco Lavra , David Matlack Content-Type: text/plain; charset="UTF-8" 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 --- 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); -- 2.49.0.1151.ga128411c76-goog