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=-7.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 3C64FC433E6 for ; Thu, 7 Jan 2021 15:01:59 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E8B4C224D3 for ; Thu, 7 Jan 2021 15:01:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E8B4C224D3 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.62943.111682 (Exim 4.92) (envelope-from ) id 1kxWnC-0000eS-CA; Thu, 07 Jan 2021 15:01:38 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 62943.111682; Thu, 07 Jan 2021 15:01:38 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kxWnC-0000eL-8u; Thu, 07 Jan 2021 15:01:38 +0000 Received: by outflank-mailman (input) for mailman id 62943; Thu, 07 Jan 2021 15:01:37 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kxWnB-0000eG-8j for xen-devel@lists.xenproject.org; Thu, 07 Jan 2021 15:01:37 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 0a684ab0-fb3a-4cad-a72f-eaef595dbb97; Thu, 07 Jan 2021 15:01:35 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C12A9ACAF; Thu, 7 Jan 2021 15:01:34 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 0a684ab0-fb3a-4cad-a72f-eaef595dbb97 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1610031694; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=b2d3XLpkpNlhWp1MGwdKBhDHK2qlfncY4GZ3KtJypuk=; b=ORUCLpXWOAG13MFvRKExtDAD/ysGh/8f+qxPMDmnZNHFCt38C/hL2T2N1lZlruTphRDp8U 78O/m0t35ofn5gbx9ymQmwjyVL5RLyO6IRu28ytQSY15fV64fxJSc7o0y/EEYhciWfncm8 7BxpIySpdJ6Yr1n3DgWapyfRx80jRi4= Subject: Re: [PATCH V3 09/23] xen/dm: Make x86's DM feature common To: Oleksandr Cc: Julien Grall , Andrew Cooper , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Wei Liu , George Dunlap , Ian Jackson , Julien Grall , Stefano Stabellini , Daniel De Graaf , Oleksandr Tyshchenko , xen-devel@lists.xenproject.org References: <1606732298-22107-1-git-send-email-olekstysh@gmail.com> <1606732298-22107-10-git-send-email-olekstysh@gmail.com> <00c3df9f-760d-bb3d-d1d6-7c7df7f0c17c@suse.com> <24191fca-78e7-3e6b-ff02-c06e8ae79f56@gmail.com> <7c985117-2bb4-dd5b-53cf-e217e25b2e8e@suse.com> <94c20a50-9363-c8d1-11aa-7a35f97a03a6@gmail.com> From: Jan Beulich Message-ID: <318580a5-d02f-9663-cc58-dfad8a4f7836@suse.com> Date: Thu, 7 Jan 2021 16:01:34 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <94c20a50-9363-c8d1-11aa-7a35f97a03a6@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 07.01.2021 15:38, Oleksandr wrote: >>> Well, on v2 you replied you didn't consider the alternative. I would >>> have expected that you would at least go through this consideration >>> process, and see whether there are better reasons to stick with the >>> apparently backwards arrangement than to change to the more >>> conventional one. If there are such reasons, I would expect them to >>> be called out in reply and perhaps also in the commit message; the >>> latter because down the road more people may wonder why the more >>> narrow / special set of cases gets handled at a higher layer than >>> the wider set of remaining ones, and they would then be able to find >>> an explanation without having to resort to searching through list >>> archives. >> Ah, will investigate. Sorry for not paying enough attention to it. >> Yes, IOREQ (I mean "common") ops are 7 out of 18 right now. The >> subsequent patch is adding one more DM op - XEN_DMOP_set_irq_level. >> There are several PCI related ops which might want to be common in the >> future (but I am not sure). > I think, I can say that I have considered the alternative (doing it the > other way around), of course if I got your suggestion for V2 correctly. > Agree, the alternative is more natural, also compat_dm_op() was left in > x86 code. For me the downside is in code duplication. With the > alternative both arches have to duplicate do_dm_op() and "common" part > of dm_op() > (only "switch ( op.op )" is unique). Yes, this duplication is the main downside. > Now the question is which approach to take ("current" or "alternative") > for me to prepare for V4. Personally, I would be OK with the both (with > a little preference for "alternative"). Same here. I don't think I've seen anyone else voice an opinion. > Also, If we decide to go with the alternative, should the common files > still be named dm.*? I think this should live in ioreq.c, just like e.g. iommu_do_pci_domctl() lives in passthrough/pci.c. This would then allow quite a few things to become static in that file, I believe. Jan