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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 8AE30C6786C for ; Fri, 12 Oct 2018 14:34:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59F9520835 for ; Fri, 12 Oct 2018 14:34:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59F9520835 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728912AbeJLWGq (ORCPT ); Fri, 12 Oct 2018 18:06:46 -0400 Received: from mga18.intel.com ([134.134.136.126]:44390 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728738AbeJLWGq (ORCPT ); Fri, 12 Oct 2018 18:06:46 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Oct 2018 07:34:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,372,1534834800"; d="scan'208";a="94673819" Received: from btwcube1.sh.intel.com (HELO debian) ([10.67.104.158]) by fmsmga002.fm.intel.com with ESMTP; 12 Oct 2018 07:34:01 -0700 Date: Fri, 12 Oct 2018 22:32:44 +0800 From: Tiwei Bie To: Jason Wang Cc: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, wexu@redhat.com, jfreimann@redhat.com, maxime.coquelin@redhat.com Subject: Re: [PATCH net-next V2 6/8] vhost: packed ring support Message-ID: <20181012143244.GA28400@debian> References: <1531711691-6769-1-git-send-email-jasowang@redhat.com> <1531711691-6769-7-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1531711691-6769-7-git-send-email-jasowang@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 16, 2018 at 11:28:09AM +0800, Jason Wang wrote: [...] > @@ -1367,10 +1397,48 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg > vq->last_avail_idx = s.num; > /* Forget the cached index value. */ > vq->avail_idx = vq->last_avail_idx; > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) { > + vq->last_avail_wrap_counter = wrap_counter; > + vq->avail_wrap_counter = vq->last_avail_wrap_counter; > + } > break; > case VHOST_GET_VRING_BASE: > s.index = idx; > s.num = vq->last_avail_idx; > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > + s.num |= vq->last_avail_wrap_counter << 31; > + if (copy_to_user(argp, &s, sizeof(s))) > + r = -EFAULT; > + break; > + case VHOST_SET_VRING_USED_BASE: > + /* Moving base with an active backend? > + * You don't want to do that. > + */ > + if (vq->private_data) { > + r = -EBUSY; > + break; > + } > + if (copy_from_user(&s, argp, sizeof(s))) { > + r = -EFAULT; > + break; > + } > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) { > + wrap_counter = s.num >> 31; > + s.num &= ~(1 << 31); > + } > + if (s.num > 0xffff) { > + r = -EINVAL; > + break; > + } Do we want to put wrap_counter at bit 15? If put wrap_counter at bit 31, the check (s.num > 0xffff) won't be able to catch the illegal index 0x8000~0xffff for packed ring. > + vq->last_used_idx = s.num; > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > + vq->last_used_wrap_counter = wrap_counter; > + break; > + case VHOST_GET_VRING_USED_BASE: Do we need the new VHOST_GET_VRING_USED_BASE and VHOST_SET_VRING_USED_BASE ops? We are going to merge below series in DPDK: http://patches.dpdk.org/patch/45874/ We may need to reach an agreement first. > + s.index = idx; > + s.num = vq->last_used_idx; > + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) > + s.num |= vq->last_used_wrap_counter << 31; > if (copy_to_user(argp, &s, sizeof s)) > r = -EFAULT; > break; [...]