From nobody Fri Dec 19 02:49:17 2025 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E0F31224224 for ; Thu, 20 Mar 2025 14:20:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742480428; cv=none; b=ApMFUnT4e+44wjKlV4IfpPjqQOkllgDCuyyPzg6vKRLwUC09vczLCqkFqIg+1BphbojEJMnj7k+vzcV5zyhrXHvQ4VufPJR+YasQUXPzTtiigjgu7hB7acyfqrMPL44gPp3i/SFYykBnCv5a/Coltqb9YKDBb13v3mSw4T6d3Fk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742480428; c=relaxed/simple; bh=xYOJlqw5etD2Iq7EXs2+mhhOT8KTP4OQ36+fvxqow4g=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=dwVYeFAjPl06xHtpFlc/Ksq+reko8LbwTkFW8u+z+yBWawd1gPc+P6Z1JJYYmpzKr0+H0goSKp7oYzCd9/2tqDgiur/JfhZQYD1EW4ouSYu7x1yvRWOZf+GeTF1E7jiR4eNmFzb/qw6+LPfGRf58zxSPFInkZVJUDZEQyc9GyCA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=d49p8fAW; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="d49p8fAW" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-22403329f9eso10697965ad.3 for ; Thu, 20 Mar 2025 07:20:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1742480426; x=1743085226; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=Xwl6R4UUQEICiZbEUz7U/9zbGoGjTM+0BWyTsj6cJLQ=; b=d49p8fAWvHaLpLV9jIBbXxpBLrPKHUugLYRDDdpwOdkCNE4LRfBdkEb8P8rrJBUIzz Mgq8gpoBco8v5cGco4VX0iYZ98ESJZTYkHRYAB4GJ7LU8lLaUhwRvhfCQMfW3ThhBNAL x7gNSJo+bnt0lNOF1P7gpD3r4uizIguzmIMjEYTe0c/K6fCq2LNNKzmxNQ1GRUGyHwIf oJxnYl+d9C/lihFDTlpB/OR+Js5E0ZMH6Nwh9PfvXwmimKNSIC1L+pvRDzHzTbWq8LLY 6ilczLPSKAot4hESOrWLKSImLQNz1S2vuC6/Fq0e9sUHC1vFvTO3EyeJll7QGx1vGNiN w0Rg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742480426; x=1743085226; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Xwl6R4UUQEICiZbEUz7U/9zbGoGjTM+0BWyTsj6cJLQ=; b=ePamq9ejy5E6jjg7h+oemaiphutUtuB41xG/xvXeL2QX37ddbL2V9LNh6Tl0CzKYc7 h32cwThSwaynAvI2tWAZEUZHuVlXNchM41iT48MO1ETJi7gJmPIEuzDbiIzD0BjLy2je qEx/8mKYe88ztWhiUfjNcwnypPvY7VpVQy96t+aKQH5Y7YXmx7QYgJZbs4pTBqwVjHhO qQkMj9liVF78RlyXXdsXYUdmYm70LNUqU62KNJvl7M4LBWJUCgotMRo2pI2kt4b4CdPt dBKgvq2C093XJ9MCwh2O8frHz71MZpE3TuPgPxVrQiSxrsvGZ7QJITDdzaPTvyC7gp/y kKwA== X-Forwarded-Encrypted: i=1; AJvYcCXjoXUc20Far5aHguH6naMZDbVYxDn8HSoOzzsl4cdfTGpTBsO1DzH+vGjxbzvS31GlqYmzQXoh+c9tLf4=@vger.kernel.org X-Gm-Message-State: AOJu0YwOQap6SSLFqy02gqrgfyHjaWgsYHN8gewLmAFeWSYAlZpJtB1g Xv5xSbYqwA1QHG6BNui5MniyaQQ90jj+qK9DKLBJ8gKK0E3Kxy6cpLYr21CA7iOARqxqMtBI4y1 fWQ== X-Google-Smtp-Source: AGHT+IFbi+MpaDJkuXF334mY8DbtKjRRtZOG3mJv7uihGv7QorWRefXzGfNReUq2gJZ504SwPNc35gRMsS0= X-Received: from plsa10.prod.google.com ([2002:a17:902:b58a:b0:226:4240:2027]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:1a2c:b0:223:5c33:56a2 with SMTP id d9443c01a7336-2265edf7ffemr63911585ad.28.1742480426260; Thu, 20 Mar 2025 07:20:26 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 20 Mar 2025 07:20:20 -0700 In-Reply-To: <20250320142022.766201-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250320142022.766201-1-seanjc@google.com> X-Mailer: git-send-email 2.49.0.395.g12beb8f557-goog Message-ID: <20250320142022.766201-2-seanjc@google.com> Subject: [PATCH v2 1/3] KVM: VMX: Don't send UNBLOCK when starting device assignment without APICv From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/posted_intr.c | 7 +++---- arch/x86/kvm/x86.c | 1 + 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index ec08fa3caf43..16121d29dfd9 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -134,9 +134,8 @@ void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) =20 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); } =20 /* @@ -254,7 +253,7 @@ 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; =20 kvm_make_all_cpus_request(kvm, KVM_REQ_UNBLOCK); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 69c20a68a3f0..f76d655dc9a8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -13554,6 +13554,7 @@ bool kvm_arch_has_irq_bypass(void) { return enable_apicv && irq_remapping_cap(IRQ_POSTING_CAP); } +EXPORT_SYMBOL_GPL(kvm_arch_has_irq_bypass); =20 int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons, struct irq_bypass_producer *prod) --=20 2.49.0.395.g12beb8f557-goog From nobody Fri Dec 19 02:49:17 2025 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DAEDB224B0C for ; Thu, 20 Mar 2025 14:20:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742480430; cv=none; b=qzfc9F2asQ5SuTwEm29jTfuQ6HDD2b9CQ7jOpwSdtFFiZHd0qDfcRITLkbaRPKK1sU6k5M7sXIbMZMwkzCYLjj02N5eb6TUpkP7Tz9bcQ7Ymzu3S6h+Ek2Xnv7JVdtEWOIpV621xDoc9DHXw/gYFlnSggeCYHTZ/W75Gmu/M0GU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742480430; c=relaxed/simple; bh=ovEPl2bVEO0eSqvBoa1vZD9IRo9Jr6lVc7JfrYVpvGg=; 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AJvYcCWFpODXu85FBmQbGYYKc7Ka/baxPokA8j8LxXa3OEu9io4zeaTb646xzqfLs47INnOcbKM0qLlpscKHIVg=@vger.kernel.org X-Gm-Message-State: AOJu0Yws1iIfMMllHd6fWglzkNQERiVQuquNKoEvDPS1WPNFxLQTc+J5 vdC9VS+cx4qEwlGsCiuL4uv77ZncEo0EvpmLMchPkB49MQNGPyf6++MMZYJWeXkGIf3Ark/rznn k7g== X-Google-Smtp-Source: AGHT+IFbPO/3Zgwol8ARgIf0jQNXI18k8lFWGe70dLm0WMUhi+BbpfRpAvT6wHo2NxigqM0VjclDH/escmU= X-Received: from pjbmf11.prod.google.com ([2002:a17:90b:184b:b0:2ef:d283:5089]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90a:d2cb:b0:2fa:42f3:e3e4 with SMTP id 98e67ed59e1d1-301d426aa83mr5355104a91.3.1742480428033; Thu, 20 Mar 2025 07:20:28 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 20 Mar 2025 07:20:21 -0700 In-Reply-To: <20250320142022.766201-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250320142022.766201-1-seanjc@google.com> X-Mailer: git-send-email 2.49.0.395.g12beb8f557-goog Message-ID: <20250320142022.766201-3-seanjc@google.com> Subject: [PATCH v2 2/3] KVM: SVM: Don't update IRTEs if APICv/AVIC is disable From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Skip IRTE updates if AVIC is disabled/unsupported, as forcing the IRTE into remapped mode (kvm_vcpu_apicv_active() will never be true) is unnecessary and wasteful. The IOMMU driver is responsible for putting IRTEs into remapped mode when an IRQ is allocated by a device, long before that device is assigned to a VM. I.e. the kernel as a whole has major issues if the IRTE isn't already in remapped mode. Opportunsitically kvm_arch_has_irq_bypass() to query for APICv/AVIC, so so that all checks in KVM x86 incorporate the same information. Cc: Yosry Ahmed Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/avic.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 65fd245a9953..901d8d2dc169 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -898,8 +898,7 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int h= ost_irq, struct kvm_irq_routing_table *irq_rt; int idx, ret =3D 0; =20 - if (!kvm_arch_has_assigned_device(kvm) || - !irq_remapping_cap(IRQ_POSTING_CAP)) + if (!kvm_arch_has_assigned_device(kvm) || !kvm_arch_has_irq_bypass()) return 0; =20 pr_debug("SVM: %s: host_irq=3D%#x, guest_irq=3D%#x, set=3D%#x\n", --=20 2.49.0.395.g12beb8f557-goog From nobody Fri Dec 19 02:49:17 2025 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5F3B2225403 for ; 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Thu, 20 Mar 2025 07:20:29 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 20 Mar 2025 07:20:22 -0700 In-Reply-To: <20250320142022.766201-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250320142022.766201-1-seanjc@google.com> X-Mailer: git-send-email 2.49.0.395.g12beb8f557-goog Message-ID: <20250320142022.766201-4-seanjc@google.com> Subject: [PATCH v2 3/3] KVM: x86: Add a module param to control and enumerate device posted IRQs From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a module param to allow disabling device posted interrupts without having to sacrifice all of APICv/AVIC, and to also effectively enumerate to userspace whether or not KVM may be utilizing device posted IRQs. Disabling device posted interrupts is very desirable for testing, and can even be desirable for production environments, e.g. if the host kernel wants to interpose on device interrupts. Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/x86.c | 9 ++++++++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_hos= t.h index d881e7d276b1..bf11c5ee50cb 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1922,6 +1922,7 @@ struct kvm_arch_async_pf { extern u32 __read_mostly kvm_nr_uret_msrs; extern bool __read_mostly allow_smaller_maxphyaddr; extern bool __read_mostly enable_apicv; +extern bool __read_mostly enable_device_posted_irqs; extern struct kvm_x86_ops kvm_x86_ops; =20 #define kvm_x86_call(func) static_call(kvm_x86_##func) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f76d655dc9a8..e7eb2198db26 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -227,6 +227,10 @@ EXPORT_SYMBOL_GPL(allow_smaller_maxphyaddr); bool __read_mostly enable_apicv =3D true; EXPORT_SYMBOL_GPL(enable_apicv); =20 +bool __read_mostly enable_device_posted_irqs =3D true; +module_param(enable_device_posted_irqs, bool, 0444); +EXPORT_SYMBOL_GPL(enable_device_posted_irqs); + const struct _kvm_stats_desc kvm_vm_stats_desc[] =3D { KVM_GENERIC_VM_STATS(), STATS_DESC_COUNTER(VM, mmu_shadow_zapped), @@ -9772,6 +9776,9 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops) if (r !=3D 0) goto out_mmu_exit; =20 + enable_device_posted_irqs &=3D enable_apicv && + irq_remapping_cap(IRQ_POSTING_CAP); + kvm_ops_update(ops); =20 for_each_online_cpu(cpu) { @@ -13552,7 +13559,7 @@ EXPORT_SYMBOL_GPL(kvm_arch_has_noncoherent_dma); =20 bool kvm_arch_has_irq_bypass(void) { - return enable_apicv && irq_remapping_cap(IRQ_POSTING_CAP); + return enable_device_posted_irqs; } EXPORT_SYMBOL_GPL(kvm_arch_has_irq_bypass); =20 --=20 2.49.0.395.g12beb8f557-goog