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=-6.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 C4D88C433E0 for ; Fri, 31 Jul 2020 10:13:15 +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 89D4A2245C for ; Fri, 31 Jul 2020 10:13:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=xen.org header.i=@xen.org header.b="CSo8bO6j" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89D4A2245C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1S21-00065V-Q8; Fri, 31 Jul 2020 10:12:53 +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 1k1S20-00065Q-MK for xen-devel@lists.xenproject.org; Fri, 31 Jul 2020 10:12:52 +0000 X-Inumbo-ID: 64463996-d316-11ea-ab98-12813bfff9fa Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 64463996-d316-11ea-ab98-12813bfff9fa; Fri, 31 Jul 2020 10:12:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=2zWe36xSudEC1Qe3mBC6X1dlmXW/MjuDSaccc+cISKY=; b=CSo8bO6jTKzu0goHo+3zVZ+IvU pfOx++B5s2NBTn0+Xs2VInSYIcZxldLqo0C9PfHFJ1xvh/2+Cc5hDDoA33M4/z/RpOFqdvQsw72N6 LHKxAmvyuTxFlZk1EZHhhsfOUCZVqvUriKfl5pP2xclx8rBteufgd4ljCQIefLJ6MBqY=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1k1S1w-0006Lx-BJ; Fri, 31 Jul 2020 10:12:48 +0000 Received: from 54-240-197-230.amazon.com ([54.240.197.230] helo=a483e7b01a66.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1k1S1w-0007A3-0X; Fri, 31 Jul 2020 10:12:48 +0000 Subject: Re: [PATCH v2] xen/arm: Convert runstate address during hypcall To: Jan Beulich , Stefano Stabellini References: <4647a019c7b42d40d3c2f5b0a3685954bea7f982.1595948219.git.bertrand.marquis@arm.com> <8d2d7f03-450c-d50c-630b-8608c6d42bb9@suse.com> <1b046f2c-05c8-9276-a91e-fd55ec098bed@suse.com> <1a8bbcc7-9d0c-9669-db7b-e837af279027@suse.com> From: Julien Grall Message-ID: <73c8ade5-36a3-cc13-80b6-bda89e175cbb@xen.org> Date: Fri, 31 Jul 2020 11:12:45 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <1a8bbcc7-9d0c-9669-db7b-e837af279027@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Wei Liu , Andrew Cooper , Ian Jackson , George Dunlap , Bertrand Marquis , Xen-devel , nd , Volodymyr Babchuk , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Hi Jan, On 31/07/2020 07:39, Jan Beulich wrote: > We're fixing other issues without breaking the ABI. Where's the > problem of backporting the kernel side change (which I anticipate > to not be overly involved)? This means you can't take advantage of the runstage on existing Linux without any modification. > If the plan remains to be to make an ABI breaking change, For a theoritical PoV, this is a ABI breakage. However, I fail to see how the restrictions added would affect OSes at least on Arm. In particular, you can't change the VA -> PA on Arm without going through an invalid mapping. So I wouldn't expect this to happen for the runstate. The only part that *may* be an issue is if the guest is registering the runstate with an initially invalid VA. Although, I have yet to see that in practice. Maybe you know? > then I > think this will need an explicit vote. I was under the impression that the two Arm maintainers (Stefano and I) already agreed with the approach here. Therefore, given the ABI breakage is only affecting Arm, why would we need a vote? Cheers, -- Julien Grall