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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 2BC95C433E6 for ; Tue, 16 Feb 2021 14:34:49 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 88C5764E07 for ; Tue, 16 Feb 2021 14:34:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88C5764E07 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:38410 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lC1R9-00021s-Lz for qemu-devel@archiver.kernel.org; Tue, 16 Feb 2021 09:34:47 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34326) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lC1Pk-0000m1-2e for qemu-devel@nongnu.org; Tue, 16 Feb 2021 09:33:20 -0500 Received: from mail-ed1-x52c.google.com ([2a00:1450:4864:20::52c]:43502) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lC1Pc-0002j0-Mc for qemu-devel@nongnu.org; Tue, 16 Feb 2021 09:33:19 -0500 Received: by mail-ed1-x52c.google.com with SMTP id r17so5825712edy.10 for ; Tue, 16 Feb 2021 06:33:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=rCtlas9S5tZJybDXLJFNv32Kg8+xEWOKSarfTFDVFY8=; b=P0S+LjetSsH8ujGe2x2nqlPGal69cTLCdvdp1lCINjfMfWJu0Fy21pyCQbIrpiIlNz 0G3bFL3GBGsUN233lT2E/feRkFtJFeJ6Y89KP9HnQT+LXyXVQlH6eOdBmR2r3I5dOgT4 +QONWd/6w+/p/s6BZ58wCV/l0E1Ob/MeAxVgNHOuLAuy2bpUx/hozSkz6SEEWPKAGzG1 K2uLaYO5kALtSnHBpIttkU2BtE7je35zF+LjH12Noj8C0DPNqZVP8TyqsF6qfZy8fbBQ xzPukRPTWuH8c57PZT7nfjUEOk6Dw5nZdV7xfDUXbXw/V7Bqg4GFlxK8bsgaxfe0hXH2 FWNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=rCtlas9S5tZJybDXLJFNv32Kg8+xEWOKSarfTFDVFY8=; b=iRMvgwxhKl1L7wzKPup/1qoqGvtJE/bFSY9Eg+ZpdEobw2f+iUG60srnR4gbWYDcHE 5IsK3jPsGQP9W31j2VWXbly8NZBz3w/yxBdVEaDPVbXmYmFfY60nM3EPkfumNiK26eN1 8AXv1/4AwY+3MzbWWhIFqZq7u0+XWUJKe0D2zAdcu2BE9ctbLOuY8XPM5C4kP1kj25Fr vOeB3+PIv24Wo69DbzLyQu47Av87voUjBUCvSgDypkFXx4UdX4BWfiVc4jsxAAtG3tVk 7M5UyDAbc2mN4mgu6UNcbxDrOnCFahskuPXX4ZdUM3WJtMIr4RzJ956fO0NqvIMyITOp 77PQ== X-Gm-Message-State: AOAM531Ox8EiI+qAODIRtHgkeKSxt53Cbkk9N5Wh75soaNEzOgu+9Uer 65HfBnqrJDBuXiFRUYevGeawLcko0771BKTu17uXAg== X-Google-Smtp-Source: ABdhPJy2Z8+5O6XedSWwGKnIcyzG7TPmXLakFRemzlsQA8XXca2GBOT1nc4nBhIiGvsgR++nz/WafSntj6+tZnSUBIw= X-Received: by 2002:a50:9e01:: with SMTP id z1mr21040803ede.44.1613485990813; Tue, 16 Feb 2021 06:33:10 -0800 (PST) MIME-Version: 1.0 References: <20210216110056.1228582-1-thuth@redhat.com> <20210216124757.4eb664e9.cohuck@redhat.com> <20210216153003.16b05725.cohuck@redhat.com> In-Reply-To: <20210216153003.16b05725.cohuck@redhat.com> From: Peter Maydell Date: Tue, 16 Feb 2021 14:32:59 +0000 Message-ID: Subject: Re: [PATCH] pc-bios/s390-ccw: Use memory barriers in virtio code To: Cornelia Huck Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2a00:1450:4864:20::52c; envelope-from=peter.maydell@linaro.org; helo=mail-ed1-x52c.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Christian Borntraeger , Thomas Huth , qemu-s390x , QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 16 Feb 2021 at 14:30, Cornelia Huck wrote: > Step 4 in "2.7.13 Supplying Buffers to The Device": > > "The driver performs a suitable memory barrier to ensure the device > sees the updated descriptor table and available ring before the next > step." I thought that my first time through the spec as well, but I think the whole of section 2.7 is dealing with "packed virtqueues", which have to be explicitly negotiated and which I don't think the s390-ccw code is doing. thnaks -- PMM