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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31F39C433F5 for ; Wed, 13 Oct 2021 20:41:49 +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 C01F6610E6 for ; Wed, 13 Oct 2021 20:41:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C01F6610E6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.208852.365102 (Exim 4.92) (envelope-from ) id 1mal3w-0003jF-8W; Wed, 13 Oct 2021 20:41:20 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 208852.365102; Wed, 13 Oct 2021 20:41:20 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mal3w-0003j8-5M; Wed, 13 Oct 2021 20:41:20 +0000 Received: by outflank-mailman (input) for mailman id 208852; Wed, 13 Oct 2021 20:41:18 +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 1mal3u-0003j1-Hj for xen-devel@lists.xenproject.org; Wed, 13 Oct 2021 20:41:18 +0000 Received: from mail.kernel.org (unknown [198.145.29.99]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id e9ed8f29-2c65-11ec-8197-12813bfff9fa; Wed, 13 Oct 2021 20:41:17 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 2869B610EA; Wed, 13 Oct 2021 20:41:16 +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: e9ed8f29-2c65-11ec-8197-12813bfff9fa DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634157676; bh=VS/ZWtlQY5x3BiVp5nUMCc80qzGBYz4TOkGlTiebOXI=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=Coqo9vQtDYkb7uOJ0iK9yo2/Z52CndQOBzM9lAAATNwSlUQtHEWNypTOZjGfsKGID vRm+a8Wo/6DIeZ2tC+viq1qFTkh9tk9Qj13jVKFGLiirdLCyCGM8fxc1s7ab8NZ7it 45m1AQfXrUAwlO6YsbPawsZ4QODwfgSJh81f0gwJ7o+krQH0UCj5PMDSfhqAEx/8cQ p5sAdO1jEX67ToLLTJWZA7v+xelr0QOJxeZgo2sn+rMfONfzCBnqIKQRheZLSgEPlJ NyUuLW9OlQJ/DaRGzBgAwiOUimRh5flG3RJim2/d7Mzo94Htp4fockkHYtUXQWuKyu qahJe/D6Iaaqg== Date: Wed, 13 Oct 2021 13:41:15 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@sstabellini-ThinkPad-T480s To: Jan Beulich cc: Bertrand Marquis , Michal Orzel , Rahul Singh , "xen-devel@lists.xenproject.org" , Andre Przywara , Christian Lindig , David Scott , Ian Jackson , Wei Liu , Andrew Cooper , George Dunlap , Julien Grall , Stefano Stabellini , Volodymyr Babchuk , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= Subject: Re: [PATCH v5 07/11] xen/domctl: Introduce XEN_DOMCTL_CDF_vpci flag In-Reply-To: Message-ID: References: <20d5b9d6a0d01a7b90711d28cbefb5701a88b438.1633540842.git.rahul.singh@arm.com> <9217a6b8-fc53-a049-7cd3-7458b574424b@arm.com> <8F9D6B9C-58CB-4000-995A-95517EE72A3B@arm.com> <9C5C0FE2-67EA-4CD7-893B-82C156F5F77A@arm.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: multipart/mixed; BOUNDARY="8323329-1357370391-1634148958=:9408" Content-ID: This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-1357370391-1634148958=:9408 Content-Type: text/plain; CHARSET=UTF-8 Content-Transfer-Encoding: 8BIT Content-ID: On Wed, 13 Oct 2021, Jan Beulich wrote: > On 13.10.2021 14:11, Bertrand Marquis wrote: > >> On 13 Oct 2021, at 11:56, Roger Pau Monné wrote: > >> If vPCI for Arm on 4.16 is not going to be functional, why so much > >> pressure in pushing those patches so fast? I understand the need to > >> remove stuff from the queue, but I don't think it's worth the cost of > >> introducing a broken interface deliberately on a release. > > +1 > > > We did not push that fast, those have been on the mailing list for a while (this is the 5th version of the serie). > > PCI passthrough is a big change requiring lots of patches and we decided to push it piece by piece to make > > the review easier. > > 5 versions for a series like this one was to be expected. Imo it has > been wrong in the past to rush in new features (even if experimental > ones) very close to the freeze, and it has mislead people to think > they can delay work until very (too?) late a point in time. Hi Roger, Jan, Let me take a few minutes to clarify and provide context for this work. I don't think anyone "pushed hard" any of the ARM series close to the release. I sent "one" email in public as a reminder of things that need reviewing: https://marc.info/?l=xen-devel&m=163373776611154 I did send a couple of private emails to Jan but they were to synchronize ourselves rather than push; Jan, I hope you didn't take them the wrong way. At the same time it is certainly true that all the people involved here worked very hard to get these series ready for 4.16. Oct 15 is the Xen Project feature freeze. It is also the deadline for many of us working with upstream Xen Project to upstream features and report back to our management. I know it doesn't affect you guys directly, but you can imagine that as employees of our respective companies we feel pressure to complete our objectives in the given timeframe. Of course we need to make sure to do that without compromising quality and without overextending upstream review capacity. The ARM PCI series are public since Dec 2020, pushed to a gitlab branch for testing: https://gitlab.com/xen-project/fusa/xen-integration/-/tree/integration/pci-passthrough I helped creating, managing and testing the branch. So, I can see why Bertrand feels like they have been around for a while: we have been dealing with these patches for almost a year, even if from a xen-devel perspective we are "only" at version 5. In the past there have been contributors dropping a large half-broken series at the last minute before the code freeze, asking for it to be committed, promising it will be improved later, and then disappearing right after the release, leaving the code half-broken forever. It is easy to draw comparisons between that kind of behavior and what is happening in this thread. We have all been burned by it at some point. However, that is really *not* what is happening this week. PCI Passthrough for ARM is a difficult feature to implement. We have been discussing it for 5+ years, close to 10 years. I know it sounds unbelievable but it is true. For one reason or the other it never materialized. Until now. Even with all the outstanding series committed, PCI Passthrough for ARM is not fully functional, but it is a lot closer to the objective. Rahul, Oleksandr and their teams have been already "sticking around" for almost a year making improvements and without their help going forward it is not going to get finished anyway. We still don't have MSI support. Given that Rahul, Oleksandr and the others are required to finish the work anyway, and they are not at risk of disappearing, I think we can deal with one or two TODO left by Oct 15 [1]. My suggestion is to accept the TODO for patch #8 [1] but I agree with Roger that we shouldn't introduce bad interfaces, especially as they impact x86 which is not "tech preview". So I think we should revert patch #7 (this patch.) I'll reply with more details in separate shorter email. [1] https://marc.info/?l=xen-devel&m=163412120531248 > In fact I'm getting somewhat angry seeing how much effort is put into > getting this work in (including myself doing reviews there), when at > the same time far older series of mine aren't given any chance to > make any progress. Not your fault, sure, but an observation. Jan, Let me start by pointing out that without your help we would never have managed to get so many ARM patches committed for 4.16. Not just PCI related, but also EFI too. You should really get credit for that. I can imagine it is frustrating helping so much somebody else but not getting help for your own series. In a way it happened to me too as the only Xilinx series outstanding didn't make any progress: https://marc.info/?l=xen-devel&m=163056545414965 The only way to solve this problem is by growing the review capacity of the community. You'll be happy to know that (without naming names) I have heard from multiple people, new members of the community, that they are going to commit time to do reviews during the next months. We are growing the community again and some of the new contributors will become good reviewers and maintainers over time. I am positive that the next 12 months will be a lot better than the last 12 months from that perspective. Thanks Jan, Roger, the two Oleksandr, Rahul, Michal, Bertrand, Luca and everyone else that stayed up late these last few weeks to push Xen forward with new groundbreaking features and pushing the project forward in new directions. I do think 4.16 is going to be a great release and the both CI-loops are still fully working with staging very close to master, further proof of the great work of this community. Cheers, Stefano --8323329-1357370391-1634148958=:9408--