From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Zhu, Lingshan" Subject: Re: [PATCH V2 2/6] kvm: detect assigned device via irqbypass manager Date: Mon, 20 Jul 2020 15:40:46 +0800 Message-ID: References: <1594898629-18790-1-git-send-email-lingshan.zhu@intel.com> <1594898629-18790-3-git-send-email-lingshan.zhu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Content-Language: en-US Sender: netdev-owner@vger.kernel.org To: Jason Wang , mst@redhat.com, alex.williamson@redhat.com, pbonzini@redhat.com, sean.j.christopherson@intel.com, wanpengli@tencent.com Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org List-Id: virtualization@lists.linuxfoundation.org On 7/17/2020 12:01 PM, Jason Wang wrote: > > On 2020/7/16 下午7:23, Zhu Lingshan wrote: >> vDPA devices has dedicated backed hardware like >> passthrough-ed devices. Then it is possible to setup irq >> offloading to vCPU for vDPA devices. Thus this patch tries to >> manipulated assigned device counters via irqbypass manager. > > > This part needs some tweak, e.g why assigned device could be detected > through this way. > > >> >> We will increase/decrease the assigned device counter in kvm/x86. > > > And you need explain why we don't need similar thing in other arch. > > Thanks OK Thanks! > > >> Both vDPA and VFIO would go through this code path. >> >> This code path only affect x86 for now. >> >> Signed-off-by: Zhu Lingshan >> Suggested-by: Jason Wang >> --- >>   arch/x86/kvm/x86.c | 10 ++++++++-- >>   1 file changed, 8 insertions(+), 2 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, >