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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3858CC43219 for ; Fri, 18 Nov 2022 01:51:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234053AbiKRBvH (ORCPT ); Thu, 17 Nov 2022 20:51:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234942AbiKRBvB (ORCPT ); Thu, 17 Nov 2022 20:51:01 -0500 Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25BBD1E71A; Thu, 17 Nov 2022 17:51:01 -0800 (PST) Received: by mail-pj1-x1031.google.com with SMTP id q1-20020a17090a750100b002139ec1e999so3724698pjk.1; Thu, 17 Nov 2022 17:51:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=NBS4FEaFHTKXaYFv2EZVW4mDEjeLzjqY4+noYhxCMC0=; b=PQJiGp8FtrzmlUizG+g1ph5MA8h5OzMv5uAA3sI+jLjxaM8z5Bw7stVBixImIawU/j qDwCW44gKY4EL2t6MknTpgzfBadhflgt1nuMyf0GuXvWzQaBiyTXiqOBpfwrHgoGX8JU hDs9EaawGpzWaKK/uH62CvcAoBpNcVNNRGmt3yQ8IuiwyafwrDt6JUWcD5j5RIm2i+Li LWxo3PVbAm/xX9oILh2qYCC9dr5VWZ7CLmpmr7cGc9ad6Fbylw30fR1/AgQHpdMRFKR8 2fZT1ARENMBLGt3WhX7OPsYObaBpZXosDwQtvBb+POv6xgkKMnbDS2MIgGDDnDNZNV9m /WYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=NBS4FEaFHTKXaYFv2EZVW4mDEjeLzjqY4+noYhxCMC0=; b=KmkcAV6ScOb1GmAEM/1vuIpwMAy8IE0V5hDoY6sfCHPvpl2Xnk7LXyAnVS3sUL7VD9 70ymaFZhHt9GzyIPFOhZ9ZM3zGa7hFPxF3BmLf2sBCrp9TIbDGlcJdz4M8tHKmfQIToA WxrWUY6FZ/OBcs6hBVjqH++ySQJSiQswqWd0wiitrFAhv/TATNiWzL6IR9JqmDZ6KkpT zOA6oN4qw9deC898uigcSiQiTXFcfBZjgQqQsfemwvrJbHDPNL9iEV9HYdSMsb1k2BUr zrKsbxxUiFS27r+avVnWcgQcCtoUBWhH12EgTkJbRNcMcs9+aMCX0ueBE/klG7Wy3k3F RfqQ== X-Gm-Message-State: ANoB5pml2RSsHgN86oBBAG3YauLs+VAMBXtBl6i5ibA3vveNknCAcINa vqts/xjBOZmBlPn9aF2/Z+c= X-Google-Smtp-Source: AA0mqf7UJgdPd4BUn/uEbwTZdqKfI8L6J8nUK3uXEaa7odzb6UBilqbNmtt/Uj6H4wDYtK/+YNamhg== X-Received: by 2002:a17:902:a508:b0:17c:7aaa:c67d with SMTP id s8-20020a170902a50800b0017c7aaac67dmr5225945plq.171.1668736260670; Thu, 17 Nov 2022 17:51:00 -0800 (PST) Received: from [192.168.43.80] (subs02-180-214-232-20.three.co.id. [180.214.232.20]) by smtp.gmail.com with ESMTPSA id h15-20020aa796cf000000b00560bb4a57f7sm1865320pfq.179.2022.11.17.17.50.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 17 Nov 2022 17:51:00 -0800 (PST) Message-ID: <73ecf737-c523-b4ab-f11f-431bb5fb2c37@gmail.com> Date: Fri, 18 Nov 2022 08:50:54 +0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH v3 2/9] Documentation: KVM: s390: Describe KVM_S390_MEMOP_F_CMPXCHG To: Janis Schoetterl-Glausch , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Alexander Gordeev Cc: David Hildenbrand , Jonathan Corbet , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-s390@vger.kernel.org, Paolo Bonzini , Shuah Khan , Sven Schnelle References: <20221117221758.66326-1-scgl@linux.ibm.com> <20221117221758.66326-3-scgl@linux.ibm.com> Content-Language: en-US From: Bagas Sanjaya In-Reply-To: <20221117221758.66326-3-scgl@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On 11/18/22 05:17, Janis Schoetterl-Glausch wrote: > +For write accesses, the KVM_S390_MEMOP_F_CMPXCHG might be supported. > +In this case, instead of doing an unconditional write, the access occurs only > +if the target location contains the "size" byte long value pointed to by > +"old_p". This is performed as an atomic cmpxchg. "size" must be a power of two > +up to and including 16. > +The value at the target location is written to the location "old_p" points to. > +If the exchange did not take place because the target value doesn't match the > +old value KVM_S390_MEMOP_R_NO_XCHG is returned. > +The KVM_S390_MEMOP_F_CMPXCHG flag is supported if KVM_CAP_S390_MEM_OP_EXTENSION > +has bit 1 (i.e. bit with value 2) set. > Is KVM_S390_MEMOP_F_CMPXCHG supported with conditions (as you implied)? -- An old man doll... just what I always wanted! - Clara