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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 39AF2C433ED for ; Mon, 12 Apr 2021 08:02:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 13AC360231 for ; Mon, 12 Apr 2021 08:02:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236974AbhDLIDP (ORCPT ); Mon, 12 Apr 2021 04:03:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230034AbhDLIDN (ORCPT ); Mon, 12 Apr 2021 04:03:13 -0400 Received: from mail-ej1-x62a.google.com (mail-ej1-x62a.google.com [IPv6:2a00:1450:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11509C061574 for ; Mon, 12 Apr 2021 01:02:56 -0700 (PDT) Received: by mail-ej1-x62a.google.com with SMTP id g17so15961620ejp.8 for ; Mon, 12 Apr 2021 01:02:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=p6jHxvinR4oy1/faml5c1RePikeItP2Kvd2rZJWrTiQ=; b=lBqfXWeW37pd7NVUT+Uk9TzwfyGZg7ekKVZcL+rLzd38GksZBKR7JgS6SVbsrGW39X 6ZQm8GNiZW6mio9p5jZdsLmscZVYaQofpMHy25hgF5Fb/qN9hrLt4VCW+2+Uo21CZy+8 g3M3iRgDWKppnOeVow7mBfNQjxGDyDBNVRnuZFyDbRSLT5wqkwDbmN+y540tFVwD9SQ5 hF8wbyI2J28YY73Rx3X4feBz2fKnwz5xghVxWzDMDLzbiyG2SK+nlXToWtL0Pd4QksMZ mVm/zIkwrIYMFJh8mZhUSIbnUq+vU+5wfLBADVijL1Z0Q4jHChPqjIGIK7Ro2tgQP9gs K8lw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=p6jHxvinR4oy1/faml5c1RePikeItP2Kvd2rZJWrTiQ=; b=Cx57oe9K7ucL9lQHWRpNcXQyu1ERe1djsxukaYSGxV8foQAunGt+fpSzkU7hXmQQVs K8cuN3eWINnwKvWIMSOASl8xU5DOcSf/BWfCx2RihffWCNDohrKuT2Pk438F863Ag61O ACIJK8os0d+DJ0nEYiOQW4SQASC159l8ADAv/R0lA0j947zk7nLL6FUa0bEXwxmurfI6 j2gIGkthoi2cUmmLReMwVihIWAcOu33JzE/p7L4L58803qTve6GzOgbo2cVfVVwql/BX PQ3gpQAsv4dTpD7grUJQX51kfBEFyFwEUFAAbi9on8V1Tqz+JAFQa2IoubIbjdYCMnCa za9A== X-Gm-Message-State: AOAM532Q9v2AqqjqkjEW3MDzacj6bpHCbuASlN6JidOP2Wn2s6BAYA0m LdC7ZQWUMUY0GKlBJ6/K79Fhqj4xdGWzxP2clwWH X-Google-Smtp-Source: ABdhPJzxBC6arRGRGNDZDQU74O/wINTe0uOldAk5rkZ3ldemXaFDnYdXEXoqOxA7hneHBKXEwp5mvfq2QIMmiuXk118= X-Received: by 2002:a17:906:36ce:: with SMTP id b14mr22328852ejc.395.1618214574855; Mon, 12 Apr 2021 01:02:54 -0700 (PDT) MIME-Version: 1.0 References: <20210331080519.172-1-xieyongji@bytedance.com> <20210331080519.172-10-xieyongji@bytedance.com> <091dde74-449b-385c-0ec9-11e4847c6c4c@redhat.com> In-Reply-To: From: Yongji Xie Date: Mon, 12 Apr 2021 16:02:44 +0800 Message-ID: Subject: Re: Re: [PATCH v6 09/10] vduse: Introduce VDUSE - vDPA Device in Userspace To: Jason Wang Cc: "Michael S. Tsirkin" , Stefan Hajnoczi , Stefano Garzarella , Parav Pandit , Christoph Hellwig , Christian Brauner , Randy Dunlap , Matthew Wilcox , viro@zeniv.linux.org.uk, Jens Axboe , bcrl@kvack.org, Jonathan Corbet , =?UTF-8?Q?Mika_Penttil=C3=A4?= , Dan Carpenter , virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Apr 12, 2021 at 3:16 PM Jason Wang wrote: > > > =E5=9C=A8 2021/4/9 =E4=B8=8B=E5=8D=884:02, Yongji Xie =E5=86=99=E9=81=93: > >>>>> +}; > >>>>> + > >>>>> +struct vduse_dev_config_data { > >>>>> + __u32 offset; /* offset from the beginning of config space */ > >>>>> + __u32 len; /* the length to read/write */ > >>>>> + __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read= /write */ > >>>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we ca= n > >>>> not change it in the future. > >>>> > >>>> So this might suffcient for future features or all type of virtio de= vices. > >>>> > >>> Do you mean 256 is no enough here=EF=BC=9F > >> Yes. > >> > > But this request will be submitted multiple times if config lengh is > > larger than 256. So do you think whether we need to extent the size to > > 512 or larger? > > > So I think you'd better either: > > 1) document the limitation (256) in somewhere, (better both uapi and doc) > But the VDUSE_CONFIG_DATA_LEN doesn't mean the limitation of configuration space. It only means the maximum size of one data transfer for configuration space. Do you mean document this? Thanks, Yongji