From patchwork Thu Feb 24 08:10:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xuan Zhuo X-Patchwork-Id: 12757986 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 DD598C433FE for ; Thu, 24 Feb 2022 08:12:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231738AbiBXIMa (ORCPT ); Thu, 24 Feb 2022 03:12:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37804 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231718AbiBXIMK (ORCPT ); Thu, 24 Feb 2022 03:12:10 -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 04126251E69; Thu, 24 Feb 2022 00:11:29 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=34;SR=0;TI=SMTPD_---0V5NDoAE_1645690283; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0V5NDoAE_1645690283) by smtp.aliyun-inc.com(127.0.0.1); Thu, 24 Feb 2022 16:11:24 +0800 From: Xuan Zhuo To: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Cc: Jeff Dike , Richard Weinberger , Anton Ivanov , "Michael S. Tsirkin" , Jason Wang , "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 , Xuan Zhuo , 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 Subject: [PATCH v6 10/26] virtio_ring: packed: implement virtqueue_reset_vring_packed() Date: Thu, 24 Feb 2022 16:10:46 +0800 Message-Id: <20220224081102.80224-11-xuanzhuo@linux.alibaba.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220224081102.80224-1-xuanzhuo@linux.alibaba.com> References: <20220224081102.80224-1-xuanzhuo@linux.alibaba.com> MIME-Version: 1.0 X-Git-Hash: bd1c915e263f Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org virtio ring supports reset. Queue reset is divided into several stages. 1. notify device queue reset 2. vring release 3. attach new vring 4. notify device queue re-enable After the first step is completed, the vring reset operation can be performed. If the newly set vring num does not change, then just reset the vq related value. Otherwise, the vring will be released and the vring will be reallocated. And the vring will be attached to the vq. If this process fails, the function will exit, and the state of the vq will be the vring release state. You can call this function again to reallocate the vring. Signed-off-by: Xuan Zhuo --- drivers/virtio/virtio_ring.c | 46 ++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index a2e771263ea7..3ee2d0e17515 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -1886,6 +1886,8 @@ static int vring_virtqueue_attach_packed(struct vring_virtqueue *vq, static void vring_virtqueue_init_packed(struct vring_virtqueue *vq, struct virtio_device *vdev) { + vq->vq.reset = VIRTIO_VQ_RESET_STEP_NONE; + vq->we_own_ring = true; vq->broken = false; vq->last_used_idx = 0; @@ -1969,6 +1971,50 @@ static struct virtqueue *vring_create_virtqueue_packed( return NULL; } +static int virtqueue_reset_vring_packed(struct virtqueue *_vq, u32 num) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + struct virtio_device *vdev = _vq->vdev; + struct vring_packed vring; + int err; + + if (num > _vq->num_max) + return -E2BIG; + + switch (vq->vq.reset) { + case VIRTIO_VQ_RESET_STEP_NONE: + return -ENOENT; + + case VIRTIO_VQ_RESET_STEP_VRING_ATTACH: + case VIRTIO_VQ_RESET_STEP_DEVICE: + if (vq->packed.vring.num == num || !num) + break; + + vring_free(_vq); + + fallthrough; + + case VIRTIO_VQ_RESET_STEP_VRING_RELEASE: + if (!num) + num = vq->packed.vring.num; + + err = vring_create_vring_packed(&vring, vdev, num); + if (err) + return -ENOMEM; + + err = vring_virtqueue_attach_packed(vq, &vring, vdev); + if (err) { + vring_free_vring_packed(&vring, vdev); + return -ENOMEM; + } + } + + vring_virtqueue_init_packed(vq, vdev); + vq->vq.reset = VIRTIO_VQ_RESET_STEP_VRING_ATTACH; + + return 0; +} + /* * Generic functions and exported symbols.