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Mon, 13 Jul 2020 08:22:44 +0000 (UTC) Received: from [10.72.13.177] (ovpn-13-177.pek2.redhat.com [10.72.13.177]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6BB4C60C84; Mon, 13 Jul 2020 08:22:35 +0000 (UTC) Subject: Re: [PATCH 3/7] vhost_vdpa: implement IRQ offloading functions in vhost_vdpa To: Zhu Lingshan , mst@redhat.com, alex.williamson@redhat.com, pbonzini@redhat.com, sean.j.christopherson@intel.com, wanpengli@tencent.com Cc: virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, netdev@vger.kernel.org, dan.daly@intel.com References: <1594565366-3195-1-git-send-email-lingshan.zhu@intel.com> <1594565366-3195-3-git-send-email-lingshan.zhu@intel.com> From: Jason Wang Message-ID: <3fb9ecfc-a325-69b5-f5b7-476a5683a324@redhat.com> Date: Mon, 13 Jul 2020 16:22:33 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1594565366-3195-3-git-send-email-lingshan.zhu@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2020/7/12 下午10:49, Zhu Lingshan wrote: > This patch introduce a set of functions for setup/unsetup > and update irq offloading respectively by register/unregister > and re-register the irq_bypass_producer. > > Signed-off-by: Zhu Lingshan > --- > drivers/vhost/vdpa.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 69 insertions(+) > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index 2fcc422..92683e4 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -115,6 +115,63 @@ static irqreturn_t vhost_vdpa_config_cb(void *private) > return IRQ_HANDLED; > } > > +static void vhost_vdpa_setup_vq_irq(struct vdpa_device *dev, int qid, int irq) > +{ > + struct vhost_vdpa *v = vdpa_get_drvdata(dev); > + struct vhost_virtqueue *vq = &v->vqs[qid]; > + int ret; > + > + vq_err(vq, "setup irq bypass for vq %d with irq = %d\n", qid, irq); > + spin_lock(&vq->call_ctx.ctx_lock); > + if (!vq->call_ctx.ctx) > + return; > + > + vq->call_ctx.producer.token = vq->call_ctx.ctx; > + vq->call_ctx.producer.irq = irq; > + ret = irq_bypass_register_producer(&vq->call_ctx.producer); > + spin_unlock(&vq->call_ctx.ctx_lock); > + > + if (unlikely(ret)) > + vq_err(vq, > + "irq bypass producer (token %p registration fails: %d\n", > + vq->call_ctx.producer.token, ret); Not sure this deserves a vq_err(), irq will be relayed through eventfd if irq bypass manager can't work. > +} > + > +static void vhost_vdpa_unsetup_vq_irq(struct vdpa_device *dev, int qid) > +{ > + struct vhost_vdpa *v = vdpa_get_drvdata(dev); > + struct vhost_virtqueue *vq = &v->vqs[qid]; > + > + spin_lock(&vq->call_ctx.ctx_lock); > + irq_bypass_unregister_producer(&vq->call_ctx.producer); > + spin_unlock(&vq->call_ctx.ctx_lock); > + > + vq_err(vq, "unsetup irq bypass for vq %d\n", qid); Why call vq_err() here? > +} > + > +static void vhost_vdpa_update_vq_irq(struct vhost_virtqueue *vq) > +{ > + struct eventfd_ctx *ctx; > + void *token; > + > + spin_lock(&vq->call_ctx.ctx_lock); > + ctx = vq->call_ctx.ctx; > + token = vq->call_ctx.producer.token; > + if (ctx == token) > + return; Need do unlock here. > + > + if (!ctx && token) > + irq_bypass_unregister_producer(&vq->call_ctx.producer); > + > + if (ctx && ctx != token) { > + irq_bypass_unregister_producer(&vq->call_ctx.producer); > + vq->call_ctx.producer.token = ctx; > + irq_bypass_register_producer(&vq->call_ctx.producer); > + } > + > + spin_unlock(&vq->call_ctx.ctx_lock); This should be rare so I'd use simple codes just do unregister and register. > +} > + > static void vhost_vdpa_reset(struct vhost_vdpa *v) > { > struct vdpa_device *vdpa = v->vdpa; > @@ -332,6 +389,7 @@ static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp) > > return 0; > } > + Unnecessary change. > static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, > void __user *argp) > { > @@ -390,6 +448,16 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, > cb.private = NULL; > } > ops->set_vq_cb(vdpa, idx, &cb); > +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS > + /* > + * if it has a non-zero irq, means there is a > + * previsouly registered irq_bypass_producer, > + * we should update it when ctx (its token) > + * changes. > + */ > + if (vq->call_ctx.producer.irq) > + vhost_vdpa_update_vq_irq(vq); > +#endif > break; > > case VHOST_SET_VRING_NUM: > @@ -741,6 +809,7 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep) > vqs[i] = &v->vqs[i]; > vqs[i]->handle_kick = handle_vq_kick; > } > + Unnecessary change. Thanks > vhost_dev_init(dev, vqs, nvqs, 0, 0, 0, false, > vhost_vdpa_process_iotlb_msg); >