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 496F1C433F5 for ; Wed, 13 Oct 2021 23:21:46 +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 0A780610CE for ; Wed, 13 Oct 2021 23:21:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 0A780610CE 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.208926.365210 (Exim 4.92) (envelope-from ) id 1manZ2-0005j6-QV; Wed, 13 Oct 2021 23:21:36 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 208926.365210; Wed, 13 Oct 2021 23:21:36 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1manZ2-0005iz-Ni; Wed, 13 Oct 2021 23:21:36 +0000 Received: by outflank-mailman (input) for mailman id 208926; Wed, 13 Oct 2021 23:21:35 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1manZ1-0005ir-L1 for xen-devel@lists.xenproject.org; Wed, 13 Oct 2021 23:21:35 +0000 Received: from mail.kernel.org (unknown [198.145.29.99]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id aff0e915-ab70-4087-9319-710dcd45e10d; Wed, 13 Oct 2021 23:21:34 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id C64C7610CE; Wed, 13 Oct 2021 23:21:32 +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: aff0e915-ab70-4087-9319-710dcd45e10d DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634167294; bh=Giumvu8A0ghOTFjjW7M5l+fqk+HGcfj12+AMFZXd0B0=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=VM+P1wTBlQX7dSUvEcyRuoZios0xsb5YXzU+ysLzquvBgfgIacBHSvC1lJa46NXmL qIz/O8zkPuwXTB51n3Z3XTHFtvXLr4za1Fx5u99dMpSSBZbXZHJRmGBbmRQcAQ0ag3 TTdOV8+NWF78XjLMZwb84NEI609/W/fE8EvHovB+etrbi9URxEqSKq4rfAySk7KgNN IkMO6TM8HL6KKs18XZUunqgdSSXG0glkxpKZXp/JFSG4m07CuMeEU2CUScCnFmz8RK 7Z3wNwXRpUFZiR6SP1wnnqydIbDnsFIOhenWKb6VFUoV8w/phjXlSFkEgNqWpzgT5j 8Fxmev0DVpazw== Date: Wed, 13 Oct 2021 16:21:30 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@sstabellini-ThinkPad-T480s To: Stefano Stabellini cc: =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= , 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 , Jan Beulich , Julien Grall , Volodymyr Babchuk 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> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: multipart/mixed; BOUNDARY="8323329-800336767-1634163118=: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. --8323329-800336767-1634163118=:9408 Content-Type: text/plain; CHARSET=UTF-8 Content-Transfer-Encoding: 8BIT Content-ID: On Wed, 13 Oct 2021, Stefano Stabellini wrote: > On Wed, 13 Oct 2021, Roger Pau Monné wrote: > > > I think the second solution is the right one but it cannot be done so near from the > > > feature freeze. > > > > > > The CDF flag as introduced right now is not creating any issue and will be used once > > > the emulation flag will be introduce. We will be able at this stage to set this properly > > > also on x86 (for dom0 pvh). > > > Moreover keeping it will allow to continue to merge the remaining part of the PCI > > > passthrough which are otherwise not possible to be done as they are dependent on this flag. > > > > > > Can we agree on keep the DOMCTL_CDF_vpci flag and introduce the emulation > > > flag on Arm after 4.16 release ? > > > > 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. > > > > I think we need to at least settle on whether we want to keep > > CDF_vpci or use an arch specific signal mechanism in order to decide > > what to do regarding the release. > > I wrote a longer separate email to provide more context about the > "pushing fast" comment. > > I agree that we don't want to introduce a bad interface. > > In regards to a way forward for 4.16, my suggestion is the following: > > - revert this patch: do not change the interface in this series > - do not change anything related to CDF_vpci for x86 > - for ARM, leave has_vpci(d) to { false } and do not set > XEN_DOMCTL_CDF_vpci > - we can discuss it in depth later on, no rush > > - in patch #10, in libxl_arm.c:libxl__arch_domain_prepare_config > - do not set XEN_DOMCTL_CDF_vpci > - do not set b_info.arch_arm.vpci > - do not define LIBXL_HAVE_BUILDINFO_ARM_VPCI in libxl.h > - keep make_vpci_node and arch_arm.vpci > > > The other patches (#1, #8, #10), which don't change any interfaces, can > still make it for 4.16 if the review feedback is addressed on time, with > one open TODO item [1]. > > This way, we get all the essential infrastructure we are trying to > introduce without making any compromises on the external interfaces. > Still it is good to have patches #1 #8 #10 so that with a trival > oneliner patch on top of 4.16 we can enable PCI for ARM and do testing > in the community, in gitlab-ci, and OSSTest too. (We have been > discussing special OSSTest flights to valide PCI passthrough as we > complete development.) One more thing: I would really like to get at least patch #8 committed because it would help with making progress with part 2 and part 3 of the PCI enablement series. My preference would also be to get #1 and #10 in as well but I feel less strongly about it. --8323329-800336767-1634163118=:9408--