From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH 2/7] kvm/vfio: detect assigned device via irqbypass manager Date: Mon, 13 Jul 2020 16:13:35 +0800 Message-ID: References: <1594565366-3195-1-git-send-email-lingshan.zhu@intel.com> <1594565366-3195-2-git-send-email-lingshan.zhu@intel.com> <20200712170518-mutt-send-email-mst@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200712170518-mutt-send-email-mst@kernel.org> Content-Language: en-US Sender: netdev-owner@vger.kernel.org To: "Michael S. Tsirkin" , Zhu Lingshan Cc: alex.williamson@redhat.com, pbonzini@redhat.com, sean.j.christopherson@intel.com, wanpengli@tencent.com, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, netdev@vger.kernel.org, dan.daly@intel.com List-Id: virtualization@lists.linuxfoundation.org On 2020/7/13 上午5:06, Michael S. Tsirkin wrote: > On Sun, Jul 12, 2020 at 10:49:21PM +0800, Zhu Lingshan wrote: >> We used to detect assigned device via VFIO manipulated device >> conters. This is less flexible consider VFIO is not the only >> interface for assigned device. vDPA devices has dedicated >> backed hardware as well. So this patch tries to detect >> the assigned device via irqbypass manager. >> >> We will increase/decrease the assigned device counter in kvm/x86. >> Both vDPA and VFIO would go through this code path. >> >> This code path only affect x86 for now. >> >> Signed-off-by: Zhu Lingshan > > I think it's best to leave VFIO alone. Add appropriate APIs for VDPA, > worry about converting existing users later. Just to make sure I understand, did you mean: 1) introduce another bridge for vDPA or 2) only detect vDPA via bypass manager? (we can leave VFIO code as is, then the assigned device counter may increase/decrease twice if VFIO use irq bypass manager which should be no harm). Thanks > >> --- >> arch/x86/kvm/x86.c | 10 ++++++++-- >> virt/kvm/vfio.c | 2 -- >> 2 files changed, 8 insertions(+), 4 deletions(-) >> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index 00c88c2..20c07d3 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -10624,11 +10624,17 @@ int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons, >> { >> struct kvm_kernel_irqfd *irqfd = >> container_of(cons, struct kvm_kernel_irqfd, consumer); >> + int ret; >> >> irqfd->producer = prod; >> + kvm_arch_start_assignment(irqfd->kvm); >> + ret = kvm_x86_ops.update_pi_irte(irqfd->kvm, >> + prod->irq, irqfd->gsi, 1); >> + >> + if (ret) >> + kvm_arch_end_assignment(irqfd->kvm); >> >> - return kvm_x86_ops.update_pi_irte(irqfd->kvm, >> - prod->irq, irqfd->gsi, 1); >> + return ret; >> } >> >> void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons, >> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c >> index 8fcbc50..111da52 100644 >> --- a/virt/kvm/vfio.c >> +++ b/virt/kvm/vfio.c >> @@ -226,7 +226,6 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) >> list_add_tail(&kvg->node, &kv->group_list); >> kvg->vfio_group = vfio_group; >> >> - kvm_arch_start_assignment(dev->kvm); >> >> mutex_unlock(&kv->lock); >> >> @@ -254,7 +253,6 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) >> continue; >> >> list_del(&kvg->node); >> - kvm_arch_end_assignment(dev->kvm); >> #ifdef CONFIG_SPAPR_TCE_IOMMU >> kvm_spapr_tce_release_vfio_group(dev->kvm, >> kvg->vfio_group); >> -- >> 1.8.3.1