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 1B2EBC433EF for ; Wed, 13 Apr 2022 03:23:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230372AbiDMDZX (ORCPT ); Tue, 12 Apr 2022 23:25:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229873AbiDMDZW (ORCPT ); Tue, 12 Apr 2022 23:25:22 -0400 Received: from out30-44.freemail.mail.aliyun.com (out30-44.freemail.mail.aliyun.com [115.124.30.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C89312E097; Tue, 12 Apr 2022 20:23:00 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;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_---0V9xgCAI_1649820174; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0V9xgCAI_1649820174) by smtp.aliyun-inc.com(127.0.0.1); Wed, 13 Apr 2022 11:22:55 +0800 Message-ID: <1649820105.687942-3-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH v9 23/32] virtio_pci: queue_reset: support VIRTIO_F_RING_RESET Date: Wed, 13 Apr 2022 11:21:45 +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, netdev@vger.kernel.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 References: <20220406034346.74409-1-xuanzhuo@linux.alibaba.com> <20220406034346.74409-24-xuanzhuo@linux.alibaba.com> In-Reply-To: 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 Tue, 12 Apr 2022 15:07:58 +0800, Jason Wang wrote: > > =E5=9C=A8 2022/4/6 =E4=B8=8A=E5=8D=8811:43, 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. notify the device to reset the queue > > 2. recycle the buffer submitted > > 3. reset the vring (may re-alloc) > > 4. 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 | 84 ++++++++++++++++++++++++++++++ > > drivers/virtio/virtio_ring.c | 2 + > > include/linux/virtio.h | 1 + > > 4 files changed, 92 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) { > > > On which condition that we may hit this path? > > > > + 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..cb5d38f1c9c8 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 +202,83 @@ 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; > > + > > + 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); > > + > > + /* For the case where vq has an exclusive irq, to prevent the irq from > > + * being received again and the pending irq, call disable_irq(). > > + * > > + * In the scenario based on shared interrupts, vq will be searched fr= om > > + * the queue virtqueues. Since the previous list_del() has been delet= ed > > + * from the queue, it is impossible for vq to be called in this case. > > + * There is no need to close the corresponding interrupt. > > + */ > > + if (vp_dev->per_vq_vectors && info->msix_vector !=3D VIRTIO_MSI_NO_VE= CTOR) > > + disable_irq(pci_irq_vector(vp_dev->pci_dev, info->msix_vector)); > > > See the previous discussion and the revert of the first try to harden > the interrupt. We probably can't use disable_irq() since it conflicts > with the affinity managed IRQ that is used by some drivers. > > We need to use synchonize_irq() and per virtqueue flag instead. As > mentioned in previous patches, this could be done on top of my rework on > the IRQ hardening . OK, the next version will contain hardened features by per virtqueue flag. Thanks. > > > > + > > + vq->reset =3D true; > > + > > + 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) > > + 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); > > + > > + if (vp_dev->per_vq_vectors && info->msix_vector !=3D VIRTIO_MSI_NO_VE= CTOR) > > + enable_irq(pci_irq_vector(vp_dev->pci_dev, info->msix_vector)); > > > We had the same issue as disable_irq(). > > Thanks > > > > + > > + vq->reset =3D false; > > + > > + 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 +487,8 @@ 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 +507,8 @@ 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 */ > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > index 6250e19fc5bf..91937e21edca 100644 > > --- a/drivers/virtio/virtio_ring.c > > +++ b/drivers/virtio/virtio_ring.c > > @@ -2028,6 +2028,7 @@ static struct virtqueue *vring_create_virtqueue_p= acked( > > vq->vq.vdev =3D vdev; > > vq->vq.name =3D name; > > vq->vq.index =3D index; > > + vq->vq.reset =3D false; > > vq->notify =3D notify; > > vq->weak_barriers =3D weak_barriers; > > > > @@ -2508,6 +2509,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned = int index, > > vq->vq.vdev =3D vdev; > > vq->vq.name =3D name; > > vq->vq.index =3D index; > > + vq->vq.reset =3D false; > > vq->notify =3D notify; > > vq->weak_barriers =3D weak_barriers; > > > > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > > index c86ff02e0ca0..33ab003c5100 100644 > > --- a/include/linux/virtio.h > > +++ b/include/linux/virtio.h > > @@ -33,6 +33,7 @@ struct virtqueue { > > unsigned int num_free; > > unsigned int num_max; > > void *priv; > > + bool reset; > > }; > > > > int virtqueue_add_outbuf(struct virtqueue *vq, >