From mboxrd@z Thu Jan 1 00:00:00 1970 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 3CEBDC433FE for ; Wed, 9 Mar 2022 09:34:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229989AbiCIJfH (ORCPT ); Wed, 9 Mar 2022 04:35:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232134AbiCIJfH (ORCPT ); Wed, 9 Mar 2022 04:35:07 -0500 Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD72C6E7AB; Wed, 9 Mar 2022 01:34:06 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=33;SR=0;TI=SMTPD_---0V6j5vtI_1646818439; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0V6j5vtI_1646818439) by smtp.aliyun-inc.com(127.0.0.1); Wed, 09 Mar 2022 17:34:01 +0800 Message-ID: <1646818328.2590482-9-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH v7 17/26] virtio_pci: queue_reset: support VIRTIO_F_RING_RESET Date: Wed, 9 Mar 2022 17:32:08 +0800 From: Xuan Zhuo To: Jason Wang Cc: Jeff Dike , Richard Weinberger , Anton Ivanov , "Michael S. Tsirkin" , "David S. Miller" , Jakub Kicinski , Hans de Goede , Mark Gross , Vadim Pasternak , Bjorn Andersson , Mathieu Poirier , Cornelia Huck , Halil Pasic , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Alexander Gordeev , Sven Schnelle , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Johannes Berg , Vincent Whitchurch , linux-um@lists.infradead.org, platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, bpf@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org References: <20220308123518.33800-1-xuanzhuo@linux.alibaba.com> <20220308123518.33800-18-xuanzhuo@linux.alibaba.com> <8b9d337d-71c2-07b4-8e65-6f83cf09bf7a@redhat.com> In-Reply-To: <8b9d337d-71c2-07b4-8e65-6f83cf09bf7a@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On Wed, 9 Mar 2022 16:54:10 +0800, Jason Wang wrote: > > =E5=9C=A8 2022/3/8 =E4=B8=8B=E5=8D=888:35, Xuan Zhuo =E5=86=99=E9=81=93: > > This patch implements virtio pci support for QUEUE RESET. > > > > Performing reset on a queue is divided into these steps: > > > > 1. virtio_reset_vq() - notify the device to reset the qu= eue > > 2. virtqueue_detach_unused_buf() - recycle the buffer submitted > > 3. virtqueue_reset_vring() - reset the vring (may re-alloc) > > 4. virtio_enable_resetq() - mmap vring to device, and enable = the queue > > > > This patch implements virtio_reset_vq(), virtio_enable_resetq() in the > > pci scenario. > > > > Signed-off-by: Xuan Zhuo > > --- > > drivers/virtio/virtio_pci_common.c | 8 +-- > > drivers/virtio/virtio_pci_modern.c | 83 ++++++++++++++++++++++++++++++ > > 2 files changed, 88 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio= _pci_common.c > > index fdbde1db5ec5..863d3a8a0956 100644 > > --- a/drivers/virtio/virtio_pci_common.c > > +++ b/drivers/virtio/virtio_pci_common.c > > @@ -248,9 +248,11 @@ static void vp_del_vq(struct virtqueue *vq) > > struct virtio_pci_vq_info *info =3D vp_dev->vqs[vq->index]; > > unsigned long flags; > > > > - spin_lock_irqsave(&vp_dev->lock, flags); > > - list_del(&info->node); > > - spin_unlock_irqrestore(&vp_dev->lock, flags); > > + if (!vq->reset) { > > + spin_lock_irqsave(&vp_dev->lock, flags); > > + list_del(&info->node); > > + spin_unlock_irqrestore(&vp_dev->lock, flags); > > + } > > > > vp_dev->del_vq(info); > > kfree(info); > > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio= _pci_modern.c > > index 49a4493732cf..3c67d3607802 100644 > > --- a/drivers/virtio/virtio_pci_modern.c > > +++ b/drivers/virtio/virtio_pci_modern.c > > @@ -34,6 +34,9 @@ static void vp_transport_features(struct virtio_devic= e *vdev, u64 features) > > if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) && > > pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV)) > > __virtio_set_bit(vdev, VIRTIO_F_SR_IOV); > > + > > + if (features & BIT_ULL(VIRTIO_F_RING_RESET)) > > + __virtio_set_bit(vdev, VIRTIO_F_RING_RESET); > > } > > > > /* virtio config->finalize_features() implementation */ > > @@ -199,6 +202,82 @@ static int vp_active_vq(struct virtqueue *vq, u16 = msix_vec) > > return 0; > > } > > > > +static int vp_modern_reset_vq(struct virtqueue *vq) > > +{ > > + struct virtio_pci_device *vp_dev =3D to_vp_device(vq->vdev); > > + struct virtio_pci_modern_device *mdev =3D &vp_dev->mdev; > > + struct virtio_pci_vq_info *info; > > + unsigned long flags; > > + unsigned int irq; > > + > > + if (!virtio_has_feature(vq->vdev, VIRTIO_F_RING_RESET)) > > + return -ENOENT; > > + > > + vp_modern_set_queue_reset(mdev, vq->index); > > + > > + info =3D vp_dev->vqs[vq->index]; > > + > > + /* delete vq from irq handler */ > > + spin_lock_irqsave(&vp_dev->lock, flags); > > + list_del(&info->node); > > + spin_unlock_irqrestore(&vp_dev->lock, flags); > > + > > + INIT_LIST_HEAD(&info->node); > > + > > + vq->reset =3D VIRTIO_VQ_RESET_STEP_DEVICE; > > + > > + /* sync irq callback. */ > > + if (vp_dev->intx_enabled) { > > + irq =3D vp_dev->pci_dev->irq; > > + > > + } else { > > + if (info->msix_vector =3D=3D VIRTIO_MSI_NO_VECTOR) > > + return 0; > > + > > + irq =3D pci_irq_vector(vp_dev->pci_dev, info->msix_vector); > > + } > > + > > + synchronize_irq(irq); > > > Synchronize_irq() is not sufficient here since it breaks the effort of > the interrupt hardening which is done by commits: > > 080cd7c3ac87 virtio-pci: harden INTX interrupts > 9e35276a5344 virtio_pci: harden MSI-X interrupts > > Unfortunately=C2=A0 080cd7c3ac87 introduces an issue that disable_irq() w= ere > used for the affinity managed irq but we're discussing a fix. I need to understand it first. > > > > + > > + return 0; > > +} > > + > > +static int vp_modern_enable_reset_vq(struct virtqueue *vq) > > +{ > > + struct virtio_pci_device *vp_dev =3D to_vp_device(vq->vdev); > > + struct virtio_pci_modern_device *mdev =3D &vp_dev->mdev; > > + struct virtio_pci_vq_info *info; > > + unsigned long flags, index; > > + int err; > > + > > + if (vq->reset !=3D VIRTIO_VQ_RESET_STEP_VRING_ATTACH) > > + return -EBUSY; > > + > > + index =3D vq->index; > > + info =3D vp_dev->vqs[index]; > > + > > + /* check queue reset status */ > > + if (vp_modern_get_queue_reset(mdev, index) !=3D 1) > > + return -EBUSY; > > + > > + err =3D vp_active_vq(vq, info->msix_vector); > > + if (err) > > + return err; > > + > > + if (vq->callback) { > > + spin_lock_irqsave(&vp_dev->lock, flags); > > + list_add(&info->node, &vp_dev->virtqueues); > > + spin_unlock_irqrestore(&vp_dev->lock, flags); > > + } else { > > + INIT_LIST_HEAD(&info->node); > > + } > > + > > + vp_modern_set_queue_enable(&vp_dev->mdev, index, true); > > > Any reason we need to check queue_enable() here? The purpose of this function is to enable a reset vq, so call queue_enable(= ) to activate it. Thanks. > > Thanks > > > > + vq->reset =3D VIRTIO_VQ_RESET_STEP_NONE; > > + > > + return 0; > > +} > > + > > static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vec= tor) > > { > > return vp_modern_config_vector(&vp_dev->mdev, vector); > > @@ -407,6 +486,8 @@ static const struct virtio_config_ops virtio_pci_co= nfig_nodev_ops =3D { > > .set_vq_affinity =3D vp_set_vq_affinity, > > .get_vq_affinity =3D vp_get_vq_affinity, > > .get_shm_region =3D vp_get_shm_region, > > + .reset_vq =3D vp_modern_reset_vq, > > + .enable_reset_vq =3D vp_modern_enable_reset_vq, > > }; > > > > static const struct virtio_config_ops virtio_pci_config_ops =3D { > > @@ -425,6 +506,8 @@ static const struct virtio_config_ops virtio_pci_co= nfig_ops =3D { > > .set_vq_affinity =3D vp_set_vq_affinity, > > .get_vq_affinity =3D vp_get_vq_affinity, > > .get_shm_region =3D vp_get_shm_region, > > + .reset_vq =3D vp_modern_reset_vq, > > + .enable_reset_vq =3D vp_modern_enable_reset_vq, > > }; > > > > /* the PCI probing function */ >