From nobody Tue Jun 30 10:17:54 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 3618EC433F5 for ; Wed, 19 Jan 2022 13:24:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354798AbiASNYi (ORCPT ); Wed, 19 Jan 2022 08:24:38 -0500 Received: from mx315.baidu.com ([180.101.52.204]:35294 "EHLO njjs-sys-mailin04.njjs.baidu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1350184AbiASNYb (ORCPT ); Wed, 19 Jan 2022 08:24:31 -0500 X-Greylist: delayed 606 seconds by postgrey-1.27 at vger.kernel.org; Wed, 19 Jan 2022 08:24:30 EST Received: from bjhw-sys-rpm015653cc5.bjhw.baidu.com (bjhw-sys-rpm015653cc5.bjhw.baidu.com [10.227.53.39]) by njjs-sys-mailin04.njjs.baidu.com (Postfix) with ESMTP id 8FCFB11800042; Wed, 19 Jan 2022 21:14:21 +0800 (CST) Received: from localhost (localhost [127.0.0.1]) by bjhw-sys-rpm015653cc5.bjhw.baidu.com (Postfix) with ESMTP id 6EB4DD9932; Wed, 19 Jan 2022 21:14:21 +0800 (CST) From: Yuan ZhaoXiong To: pbonzini@redhat.com, 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, hpa@zytor.com Cc: lirongqing@baidu.com, kvm@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v1] KVM: X86: Introduce vfio_intr_stat per-vm debugfs file Date: Wed, 19 Jan 2022 21:14:21 +0800 Message-Id: <1642598061-29454-1-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 --- diff with v0: modifying the code format. 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 9240b3b..be16bfe 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; @@ -181,9 +186,94 @@ 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_kernel_irq_routing_entry *e; + struct kvm_irq_routing_table *irq_rt; + unsigned int host_irq, guest_irq; + struct kvm_kernel_irqfd *irqfd; + struct kvm *kvm =3D m->private; + struct kvm_lapic_irq irq; + struct kvm_vcpu *vcpu; + int idx; + + 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