From patchwork Tue Jul 26 07:22:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xuan Zhuo X-Patchwork-Id: 12928920 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 71A1BCCA48F for ; Tue, 26 Jul 2022 07:24:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238016AbiGZHYY (ORCPT ); Tue, 26 Jul 2022 03:24:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238239AbiGZHXb (ORCPT ); Tue, 26 Jul 2022 03:23:31 -0400 Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB51A2B268; Tue, 26 Jul 2022 00:23:22 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R711e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=37;SR=0;TI=SMTPD_---0VKUB8yj_1658820192; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0VKUB8yj_1658820192) by smtp.aliyun-inc.com; Tue, 26 Jul 2022 15:23:13 +0800 From: Xuan Zhuo To: virtualization@lists.linux-foundation.org Cc: Richard Weinberger , Anton Ivanov , Johannes Berg , "Michael S. Tsirkin" , Jason Wang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Hans de Goede , Mark Gross , Vadim Pasternak , Bjorn Andersson , Mathieu Poirier , Cornelia Huck , Halil Pasic , Eric Farman , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Xuan Zhuo , 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, kangjie.xu@linux.alibaba.com Subject: [PATCH v13 24/42] virtio_ring: introduce virtqueue_resize() Date: Tue, 26 Jul 2022 15:22:07 +0800 Message-Id: <20220726072225.19884-25-xuanzhuo@linux.alibaba.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220726072225.19884-1-xuanzhuo@linux.alibaba.com> References: <20220726072225.19884-1-xuanzhuo@linux.alibaba.com> MIME-Version: 1.0 X-Git-Hash: 19d2a6aae0b1 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Introduce virtqueue_resize() to implement the resize of vring. Based on these, the driver can dynamically adjust the size of the vring. For example: ethtool -G. virtqueue_resize() implements resize based on the vq reset function. In case of failure to allocate a new vring, it will give up resize and use the original vring. During this process, if the re-enable reset vq fails, the vq can no longer be used. Although the probability of this situation is not high. The parameter recycle is used to recycle the buffer that is no longer used. Signed-off-by: Xuan Zhuo Acked-by: Jason Wang --- drivers/virtio/virtio_ring.c | 69 ++++++++++++++++++++++++++++++++++++ include/linux/virtio.h | 3 ++ 2 files changed, 72 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 98bac8c389e8..140b13693a98 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -2538,6 +2538,75 @@ struct virtqueue *vring_create_virtqueue( } EXPORT_SYMBOL_GPL(vring_create_virtqueue); +/** + * virtqueue_resize - resize the vring of vq + * @_vq: the struct virtqueue we're talking about. + * @num: new ring num + * @recycle: callback for recycle the useless buffer + * + * When it is really necessary to create a new vring, it will set the current vq + * into the reset state. Then call the passed callback to recycle the buffer + * that is no longer used. Only after the new vring is successfully created, the + * old vring will be released. + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * Returns zero or a negative error. + * 0: success. + * -ENOMEM: Failed to allocate a new ring, fall back to the original ring size. + * vq can still work normally + * -EBUSY: Failed to sync with device, vq may not work properly + * -ENOENT: Transport or device not supported + * -E2BIG/-EINVAL: num error + * -EPERM: Operation not permitted + * + */ +int virtqueue_resize(struct virtqueue *_vq, u32 num, + void (*recycle)(struct virtqueue *vq, void *buf)) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + struct virtio_device *vdev = vq->vq.vdev; + void *buf; + int err; + + if (!vq->we_own_ring) + return -EPERM; + + if (num > vq->vq.num_max) + return -E2BIG; + + if (!num) + return -EINVAL; + + if ((vq->packed_ring ? vq->packed.vring.num : vq->split.vring.num) == num) + return 0; + + if (!vdev->config->disable_vq_and_reset) + return -ENOENT; + + if (!vdev->config->enable_vq_after_reset) + return -ENOENT; + + err = vdev->config->disable_vq_and_reset(_vq); + if (err) + return err; + + while ((buf = virtqueue_detach_unused_buf(_vq)) != NULL) + recycle(_vq, buf); + + if (vq->packed_ring) + err = virtqueue_resize_packed(_vq, num); + else + err = virtqueue_resize_split(_vq, num); + + if (vdev->config->enable_vq_after_reset(_vq)) + return -EBUSY; + + return err; +} +EXPORT_SYMBOL_GPL(virtqueue_resize); + /* Only available for split ring */ struct virtqueue *vring_new_virtqueue(unsigned int index, unsigned int num, diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 129bde7521e3..62e31bca5602 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -91,6 +91,9 @@ dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq); dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq); dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq); +int virtqueue_resize(struct virtqueue *vq, u32 num, + void (*recycle)(struct virtqueue *vq, void *buf)); + /** * virtio_device - representation of a device using virtio * @index: unique position on the virtio bus