From nobody Wed Jul 1 04:19:27 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B259C433F5 for ; Fri, 31 Dec 2021 08:24:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242827AbhLaIYj (ORCPT ); Fri, 31 Dec 2021 03:24:39 -0500 Received: from mx411.baidu.com ([124.64.200.154]:4292 "EHLO mx423.baidu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S230180AbhLaIYh (ORCPT ); Fri, 31 Dec 2021 03:24:37 -0500 X-Greylist: delayed 944 seconds by postgrey-1.27 at vger.kernel.org; Fri, 31 Dec 2021 03:24:36 EST Received: from bjhw-sys-rpm015653cc5.bjhw.baidu.com (bjhw-sys-rpm015653cc5.bjhw.baidu.com [10.227.53.39]) by mx423.baidu.com (Postfix) with ESMTP id B9EDE16E00515; Fri, 31 Dec 2021 16:08:43 +0800 (CST) Received: from localhost (localhost [127.0.0.1]) by bjhw-sys-rpm015653cc5.bjhw.baidu.com (Postfix) with ESMTP id AB2D1D9932; Fri, 31 Dec 2021 16:08:43 +0800 (CST) From: Yuan ZhaoXiong To: pbonzini@redhat.com Cc: seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, lirongqing@baidu.com Subject: [PATCH] KVM: X86: Introduce vfio_intr_stat per-vm debugfs file Date: Fri, 31 Dec 2021 16:08:43 +0800 Message-Id: <1640938123-33742-1-git-send-email-yuanzhaoxiong@baidu.com> X-Mailer: git-send-email 1.7.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Use this file to export correspondence between guest_irq, host_irq, vector and vcpu belonging to VFIO passthrough devices. An example output of this looks like (a vm with VFIO passthrough devices): guest_irq host_irq vector vcpu 24 201 37 8 25 202 35 25 26 203 35 20 ...... When a VM has VFIO passthrough devices, the correspondence between guest_irq, host_irq, vector and vcpu may need to be known especially in AMD platform with avic disabled. The AMD avic is disabled, and the passthrough devices may cause vcpu vm exit twice for a interrupt. One extrernal interrupt caused by vfio host irq, other ipi to inject a interrupt to vm. If the system administrator known these information, set vfio host irq affinity to Pcpu which the correspondece guest irq affinited vcpu, to avoid extra vm exit. Co-developed-by: Li RongQing Signed-off-by: Li RongQing Signed-off-by: Yuan ZhaoXiong --- arch/x86/kvm/debugfs.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++= ++++ 1 file changed, 90 insertions(+) diff --git a/arch/x86/kvm/debugfs.c b/arch/x86/kvm/debugfs.c index 54a83a7..d86213e 100644 --- a/arch/x86/kvm/debugfs.c +++ b/arch/x86/kvm/debugfs.c @@ -10,6 +10,11 @@ #include "mmu.h" #include "mmu/mmu_internal.h" =20 +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS +#include +#include +#endif + static int vcpu_get_timer_advance_ns(void *data, u64 *val) { struct kvm_vcpu *vcpu =3D (struct kvm_vcpu *) data; @@ -178,9 +183,94 @@ static int kvm_mmu_rmaps_stat_release(struct inode *in= ode, struct file *file) .release =3D kvm_mmu_rmaps_stat_release, }; =20 +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS +static int kvm_vfio_intr_stat_show(struct seq_file *m, void *v) +{ + struct kvm *kvm =3D m->private; + struct kvm_kernel_irqfd *irqfd; + struct kvm_kernel_irq_routing_entry *e; + struct kvm_irq_routing_table *irq_rt; + struct kvm_lapic_irq irq; + struct kvm_vcpu *vcpu; + int idx; + unsigned int host_irq, guest_irq; + + if (!kvm_arch_has_assigned_device(kvm) || + !irq_remapping_cap(IRQ_POSTING_CAP)) { + return 0; + } + + seq_printf(m, "%12s %12s %12s %12s\n", + "guest_irq", "host_irq", "vector", "vcpu"); + + spin_lock_irq(&kvm->irqfds.lock); + idx =3D srcu_read_lock(&kvm->irq_srcu); + irq_rt =3D srcu_dereference(kvm->irq_routing, &kvm->irq_srcu); + + list_for_each_entry(irqfd, &kvm->irqfds.items, list) { + if (!irqfd->producer) + continue; + + host_irq =3D irqfd->producer->irq; + guest_irq =3D irqfd->gsi; + + if (guest_irq >=3D irq_rt->nr_rt_entries || + hlist_empty(&irq_rt->map[guest_irq])) { + pr_warn_once("no route for guest_irq %u/%u (broken user space?)\n", + guest_irq, irq_rt->nr_rt_entries); + continue; + } + + hlist_for_each_entry(e, &irq_rt->map[guest_irq], link) { + if (e->type !=3D KVM_IRQ_ROUTING_MSI) + continue; + + kvm_set_msi_irq(kvm, e, &irq); + if (kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) { + seq_printf(m, "%12u %12u %12u %12u\n", + guest_irq, host_irq, irq.vector, vcpu->vcpu_id); + } + } + } + srcu_read_unlock(&kvm->irq_srcu, idx); + spin_unlock_irq(&kvm->irqfds.lock); + return 0; +} + +static int kvm_vfio_intr_stat_open(struct inode *inode, struct file *file) +{ + struct kvm *kvm =3D inode->i_private; + + if (!kvm_get_kvm_safe(kvm)) + return -ENOENT; + + return single_open(file, kvm_vfio_intr_stat_show, kvm); +} + +static int kvm_vfio_intr_stat_release(struct inode *inode, struct file *fi= le) +{ + struct kvm *kvm =3D inode->i_private; + + kvm_put_kvm(kvm); + return single_release(inode, file); +} + +static const struct file_operations vfio_intr_stat_fops =3D { + .open =3D kvm_vfio_intr_stat_open, + .read =3D seq_read, + .llseek =3D seq_lseek, + .release =3D kvm_vfio_intr_stat_release, +}; +#endif + int kvm_arch_create_vm_debugfs(struct kvm *kvm) { debugfs_create_file("mmu_rmaps_stat", 0644, kvm->debugfs_dentry, kvm, &mmu_rmaps_stat_fops); + +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS + debugfs_create_file("vfio_intr_stat", 0444, kvm->debugfs_dentry, kvm, + &vfio_intr_stat_fops); +#endif return 0; } --=20 1.8.3.1