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 X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F065AC433F5 for ; Thu, 9 Sep 2021 09:57:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C959D60F13 for ; Thu, 9 Sep 2021 09:57:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233312AbhIIJ6i (ORCPT ); Thu, 9 Sep 2021 05:58:38 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:53413 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232630AbhIIJ6h (ORCPT ); Thu, 9 Sep 2021 05:58:37 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R791e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04400;MF=wuzongyong@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0UnnC6zL_1631181446; Received: from localhost(mailfrom:wuzongyong@linux.alibaba.com fp:SMTPD_---0UnnC6zL_1631181446) by smtp.aliyun-inc.com(127.0.0.1); Thu, 09 Sep 2021 17:57:26 +0800 Date: Thu, 9 Sep 2021 17:57:26 +0800 From: Wu Zongyong To: Jason Wang Cc: virtualization , linux-kernel , mst , wei.yang1@linux.alibaba.com Subject: Re: [PATCH 5/6] vdpa: add get_vq_num_unchangeable callback in vdpa_config_ops Message-ID: <20210909095726.GA17469@L-PF27918B-1352.localdomain> Reply-To: Wu Zongyong References: <20210909080157.GA17383@L-PF27918B-1352.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 09, 2021 at 05:28:26PM +0800, Jason Wang wrote: > On Thu, Sep 9, 2021 at 4:02 PM Wu Zongyong wrote: > > > > On Thu, Sep 09, 2021 at 10:55:03AM +0800, Jason Wang wrote: > > > On Wed, Sep 8, 2021 at 8:23 PM Wu Zongyong wrote: > > > > > > > > This new callback is used to indicate whether the vring size can be > > > > change or not. It is useful when we have a legacy virtio pci device as > > > > the vdpa device for there is no way to negotiate the vring num by the > > > > specification. > > > > > > So I'm not sure it's worth bothering. E.g what if we just fail > > > VHOST_SET_VRING_NUM it the value doesn't match what hardware has? > > > > > > Thanks > > > > > I think we should not call VHOST_SET_VRING_NUM in that case. > > > > If the hardware reports that the virtqueue size cannot be changed, we > > should call VHOST_GET_VRING_NUM to get the static virtqueue size > > firstly, then allocate the same size memory for the virtqueues and write > > the address to hardware finally. > > > > For QEMU, we will ignore the properties rx/tx_queue_size and just get it > > from the hardware if this new callback return true. > > This will break live migration. My understanding is that we can > advertise those capability/limitation via the netlink management > protocol then management layer can choose to use the correct queue > size. > > Thanks I agree, it is a good idea. BTW, can we also advertise mac address of network device? I found the mac address generated by libvirt or qemu will break the network datapath down if I don't specify the right mac explicitly in the XML or qemu commandline. > > > > > What do you think? > > > > > > > > Signed-off-by: Wu Zongyong > > > > --- > > > > drivers/vhost/vdpa.c | 19 +++++++++++++++++++ > > > > drivers/virtio/virtio_vdpa.c | 5 ++++- > > > > include/linux/vdpa.h | 4 ++++ > > > > include/uapi/linux/vhost.h | 2 ++ > > > > 4 files changed, 29 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > > > > index 9479f7f79217..2204d27d1e5d 100644 > > > > --- a/drivers/vhost/vdpa.c > > > > +++ b/drivers/vhost/vdpa.c > > > > @@ -350,6 +350,22 @@ static long vhost_vdpa_get_iova_range(struct vhost_vdpa *v, u32 __user *argp) > > > > return 0; > > > > } > > > > > > > > +static long vhost_vdpa_get_vring_num_unchangeable(struct vhost_vdpa *v, > > > > + u32 __user *argp) > > > > +{ > > > > + struct vdpa_device *vdpa = v->vdpa; > > > > + const struct vdpa_config_ops *ops = vdpa->config; > > > > + bool unchangeable = false; > > > > + > > > > + if (ops->get_vq_num_unchangeable) > > > > + unchangeable = ops->get_vq_num_unchangeable(vdpa); > > > > + > > > > + if (copy_to_user(argp, &unchangeable, sizeof(unchangeable))) > > > > + return -EFAULT; > > > > + > > > > + return 0; > > > > +} > > > > + > > > > static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, > > > > void __user *argp) > > > > { > > > > @@ -487,6 +503,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, > > > > case VHOST_VDPA_GET_IOVA_RANGE: > > > > r = vhost_vdpa_get_iova_range(v, argp); > > > > break; > > > > + case VHOST_VDPA_GET_VRING_NUM_UNCHANGEABLE: > > > > + r = vhost_vdpa_get_vring_num_unchangeable(v, argp); > > > > + break; > > > > default: > > > > r = vhost_dev_ioctl(&v->vdev, cmd, argp); > > > > if (r == -ENOIOCTLCMD) > > > > diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c > > > > index 72eaef2caeb1..afb47465307a 100644 > > > > --- a/drivers/virtio/virtio_vdpa.c > > > > +++ b/drivers/virtio/virtio_vdpa.c > > > > @@ -146,6 +146,7 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index, > > > > struct vdpa_vq_state state = {0}; > > > > unsigned long flags; > > > > u32 align, num; > > > > + bool may_reduce_num = true; > > > > int err; > > > > > > > > if (!name) > > > > @@ -171,8 +172,10 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index, > > > > > > > > /* Create the vring */ > > > > align = ops->get_vq_align(vdpa); > > > > + if (ops->get_vq_num_unchangeable) > > > > + may_reduce_num = !ops->get_vq_num_unchangeable(vdpa); > > > > vq = vring_create_virtqueue(index, num, align, vdev, > > > > - true, true, ctx, > > > > + true, may_reduce_num, ctx, > > > > virtio_vdpa_notify, callback, name); > > > > if (!vq) { > > > > err = -ENOMEM; > > > > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h > > > > index 35648c11e312..f809b7ada00d 100644 > > > > --- a/include/linux/vdpa.h > > > > +++ b/include/linux/vdpa.h > > > > @@ -195,6 +195,9 @@ struct vdpa_iova_range { > > > > * @vdev: vdpa device > > > > * Returns the iova range supported by > > > > * the device. > > > > + * @get_vq_num_unchangeable Check if size of virtqueue is unchangeable (optional) > > > > + * @vdev: vdpa device > > > > + * Returns boolean: unchangeable (true) or not (false) > > > > * @set_map: Set device memory mapping (optional) > > > > * Needed for device that using device > > > > * specific DMA translation (on-chip IOMMU) > > > > @@ -262,6 +265,7 @@ struct vdpa_config_ops { > > > > const void *buf, unsigned int len); > > > > u32 (*get_generation)(struct vdpa_device *vdev); > > > > struct vdpa_iova_range (*get_iova_range)(struct vdpa_device *vdev); > > > > + bool (*get_vq_num_unchangeable)(struct vdpa_device *vdev); > > > > > > > > /* DMA ops */ > > > > int (*set_map)(struct vdpa_device *vdev, struct vhost_iotlb *iotlb); > > > > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h > > > > index c998860d7bbc..184f1f7f8498 100644 > > > > --- a/include/uapi/linux/vhost.h > > > > +++ b/include/uapi/linux/vhost.h > > > > @@ -150,4 +150,6 @@ > > > > /* Get the valid iova range */ > > > > #define VHOST_VDPA_GET_IOVA_RANGE _IOR(VHOST_VIRTIO, 0x78, \ > > > > struct vhost_vdpa_iova_range) > > > > +/* Check if the vring size can be change */ > > > > +#define VHOST_VDPA_GET_VRING_NUM_UNCHANGEABLE _IOR(VHOST_VIRTIO, 0X79, bool) > > > > #endif > > > > -- > > > > 2.31.1 > > > > > >