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=-5.4 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 BF77AC433E2 for ; Mon, 14 Sep 2020 09:04:54 +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 60008207C3 for ; Mon, 14 Sep 2020 09:04:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=xen.org header.i=@xen.org header.b="cRS2Yro9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 60008207C3 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 1kHkPh-0004qY-7n; Mon, 14 Sep 2020 09:04:41 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kHkPg-0004qS-46 for xen-devel@lists.xenproject.org; Mon, 14 Sep 2020 09:04:40 +0000 X-Inumbo-ID: 32a226ce-c471-44d3-9de4-c632d29fa128 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 32a226ce-c471-44d3-9de4-c632d29fa128; Mon, 14 Sep 2020 09:04:29 +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; bh=eyGsy5jZ2+w454Toz8frYA+/6ej0XHarCvFmep2QnHQ=; b=cRS2Yro9NZpMnnX3zF8o6nV50Q BzPL5DFZjGC4wrVlmjHNDHs/riVF3bn5JpofRLHwGZBMN8uFh1FOX66b+qcDjF3e201fsooC0nAhs FHqVE79SJih+6upB2OcWfK9+bRaVmEu39xEA/nivk9RDmQjCZYYCNOGbz2J7JDkFu6nU=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kHkPS-0001PL-Ba; Mon, 14 Sep 2020 09:04:26 +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 1kHkPQ-0002lX-GK; Mon, 14 Sep 2020 09:04:25 +0000 Subject: Re: [PATCH v2 2/2] xen: Introduce cmpxchg64() and guest_cmpxchg64() To: Jan Beulich Cc: xen-devel@lists.xenproject.org, oleksandr_tyshchenko@epam.com, Julien Grall , Stefano Stabellini , Volodymyr Babchuk , Andrew Cooper , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Wei Liu References: <20200911160622.19721-1-julien@xen.org> <20200911160622.19721-3-julien@xen.org> <403f8774-1ca9-560d-2ca5-fa00b64d2a98@suse.com> From: Julien Grall Message-ID: <6cb6b747-5747-e069-8133-a5268efe71db@xen.org> Date: Mon, 14 Sep 2020 10:04:22 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <403f8774-1ca9-560d-2ca5-fa00b64d2a98@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: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Hi Jan, On 14/09/2020 09:48, Jan Beulich wrote: > On 11.09.2020 18:06, Julien Grall wrote: >> --- a/xen/include/asm-x86/guest_atomics.h >> +++ b/xen/include/asm-x86/guest_atomics.h >> @@ -20,6 +20,7 @@ >> ((void)(d), test_and_change_bit(nr, p)) >> >> #define guest_cmpxchg(d, ptr, o, n) ((void)(d), cmpxchg(ptr, o, n)) >> +#define guest_cmpxchg64(d, ptr, o, n) ((void)(d), cmpxchg(ptr, o, n)) > > While them sitting side by side there's perhaps little risk of > them going out of sync with one another, I still find it a > little odd to open-code guest_cmpxchg() instead of using it, It depends on how you view it... The implementation is indeed the same but they are meant to be used in different places. Anyway... I can use: #define guest_cmpxchg64 guest_cmpxchg Cheers, -- Julien Grall