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 A545DC433EF for ; Wed, 13 Jul 2022 07:48:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234789AbiGMHsD (ORCPT ); Wed, 13 Jul 2022 03:48:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43078 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234806AbiGMHru (ORCPT ); Wed, 13 Jul 2022 03:47:50 -0400 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 506D2E5DF3 for ; Wed, 13 Jul 2022 00:47:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657698469; x=1689234469; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=Vj8X/LqF3f/wYRf5yzHwYjTsB4jiN9Wxyxci8qEo7z0=; b=ZgiftvX9Pezog6Ix/1H+EGHptgDYHk2jSJckxsTHWnvPZjDeCJtIgMcH q73UM1CSTpXDGBrQy2tskgRI+GmLCFNgO54at0ti9yNwA0kaiJfSvsj/y tb1zLYHnper6DEg1u7z41sKQ9Kko8Wgh0LiwDY/t+bTSSEFnxc7Xylo98 cNijOZu+UqgdYpnk3U1YKUwSD9qS3YwNJnKIMkaLIF8B0ykPnswAM4OsS OFWsiGAIzVsrbNgC0kjz1gYkbOAo7UOBRmWtJBS2sOeMVu/eJQRV7YCO5 Xk106ONos5bsT8x9BTBMDowjGSjmNhfZTbhsTEdOBGi6zli1IyxUxARQQ A==; X-IronPort-AV: E=McAfee;i="6400,9594,10406"; a="346821857" X-IronPort-AV: E=Sophos;i="5.92,267,1650956400"; d="scan'208";a="346821857" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jul 2022 00:47:46 -0700 X-IronPort-AV: E=Sophos;i="5.92,267,1650956400"; d="scan'208";a="628205970" Received: from lingshan-mobl.ccr.corp.intel.com (HELO [10.254.208.157]) ([10.254.208.157]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Jul 2022 00:47:42 -0700 Message-ID: Date: Wed, 13 Jul 2022 15:47:40 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.11.0 Subject: Re: [PATCH V3 5/6] vDPA: answer num of queue pairs = 1 to userspace when VIRTIO_NET_F_MQ == 0 Content-Language: en-US To: "Michael S. Tsirkin" , Parav Pandit Cc: "jasowang@redhat.com" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "xieyongji@bytedance.com" , "gautam.dawar@amd.com" References: <20220701132826.8132-1-lingshan.zhu@intel.com> <20220701132826.8132-6-lingshan.zhu@intel.com> <20220713011631-mutt-send-email-mst@kernel.org> From: "Zhu, Lingshan" In-Reply-To: <20220713011631-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 7/13/2022 1:26 PM, Michael S. Tsirkin wrote: > On Fri, Jul 01, 2022 at 10:07:59PM +0000, Parav Pandit wrote: >> >>> From: Zhu Lingshan >>> Sent: Friday, July 1, 2022 9:28 AM >>> If VIRTIO_NET_F_MQ == 0, the virtio device should have one queue pair, so >>> when userspace querying queue pair numbers, it should return mq=1 than >>> zero. >>> >>> Function vdpa_dev_net_config_fill() fills the attributions of the vDPA >>> devices, so that it should call vdpa_dev_net_mq_config_fill() so the >>> parameter in vdpa_dev_net_mq_config_fill() should be feature_device than >>> feature_driver for the vDPA devices themselves >>> >>> Before this change, when MQ = 0, iproute2 output: >>> $vdpa dev config show vdpa0 >>> vdpa0: mac 00:e8:ca:11:be:05 link up link_announce false max_vq_pairs 0 >>> mtu 1500 >>> >> The fix belongs to user space. >> When a feature bit _MQ is not negotiated, vdpa kernel space will not add attribute VDPA_ATTR_DEV_NET_CFG_MAX_VQP. >> When such attribute is not returned by kernel, max_vq_pairs should not be shown by the iproute2. >> >> We have many config space fields that depend on the feature bits and some of them do not have any defaults. >> To keep consistency of existence of config space fields among all, we don't want to show default like below. >> >> Please fix the iproute2 to not print max_vq_pairs when it is not returned by the kernel. > Parav I read the discussion and don't get your argument. From driver's POV > _MQ with 1 VQ pair and !_MQ are exactly functionally equivalent. > > It's true that iproute probably needs to be fixed too, to handle old > kernels. But iproute is not the only userspace, why not make it's life > easier by fixing the kernel? I will fix iproute2 once this series settles down Thanks, Zhu Lingshan