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=-8.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 7A7F5C4338F for ; Mon, 26 Jul 2021 12:44:46 +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 128B260F45 for ; Mon, 26 Jul 2021 12:44:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 128B260F45 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:60768 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m7zyO-00012H-Ho for qemu-devel@archiver.kernel.org; Mon, 26 Jul 2021 08:44:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44256) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m7zxC-0007wW-1S for qemu-devel@nongnu.org; Mon, 26 Jul 2021 08:43:30 -0400 Received: from mail-ej1-x632.google.com ([2a00:1450:4864:20::632]:38446) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1m7zxA-0007dn-Eu for qemu-devel@nongnu.org; Mon, 26 Jul 2021 08:43:29 -0400 Received: by mail-ej1-x632.google.com with SMTP id nd39so16243615ejc.5 for ; Mon, 26 Jul 2021 05:43:27 -0700 (PDT) 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=yZ5D/xIJ7nJcwLj4uwIq/XuR1cv1Hnm4hbKAZbIHcdI=; b=jwCkiG1mANM3wvPDIOqYo9EkAR3ZZ8JfQwai7yNskNEQYN0oSPSpnMl5GVhT1YKVJf F307+a16i0Kj5CS11W3SBLBpWEOYx3Ht6hIDLWub/jdrOw/ptOX98cX5rzeLT7AzRyk1 m7FT2DDRcNvpAtZDDsWN2fr4DpuyDwiR6ZW2aDpA6h2dMe8xqQ3dCFc82j/w+61mC3A/ CIg3nVGSHIGpq1qjEMEBnurkOdu5OBTziDSBUOZKdslO9aaenR+CYWPrEx7WQekrX3zL 3RxhtjGneGxRRhD9yVjM1/NEQ0D1VR3Ex9hCpPuzgFzdsMc2iYR5N36buwqBffnOOC69 prWQ== 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=yZ5D/xIJ7nJcwLj4uwIq/XuR1cv1Hnm4hbKAZbIHcdI=; b=qF0vDAbeyEGNJ1JMmSuU+Liu4c4MHiJ8earfE5siCCA2C3CWlTWIyrSC8/0JViAJ7J jycjWZFl/dWk/J6z7AKlLgJf5v1y4gkYAr4wt9gFkhJ1jEodCW68yFKHm1op7/KbeWQ4 56YAaSn7zGOcASFDjry1XV15fBIKAkbiMchs4QLn1ABPaaxD61MaFwkqBMGUI4lTdNER MDP8vDo96uTVgHSL/fjy6L9oYZ/3uS4ERgqfvRHgFX8cE3PrvbDFMw3D1n4A8NODXfgc mxINbQkWlGRtqFPof9Q9Ob3UL81iznUflme+mPnvjPIv9UHm7sox4FDh6Uw7+AJN13mN T4PQ== X-Gm-Message-State: AOAM532mYtbuafeMZHc5OOJ7Q081a+VltlhjUrLSq8tOPVa1vQ+aGfJD JgZ5asSKhGpG9yvvHCQSdYoZLYA1DPbx4WGxIbiDSg== X-Google-Smtp-Source: ABdhPJzxpyAxlDNrnnejhZ7OYpkTT3mG8ShPKZ2Sy00RC7hJhK1lgIF2Mrq/P3q/EFWqBggzOtA8L5qO4IGg48B4W1c= X-Received: by 2002:a17:906:d93a:: with SMTP id rn26mr3603170ejb.382.1627303406886; Mon, 26 Jul 2021 05:43:26 -0700 (PDT) MIME-Version: 1.0 References: <20210723203344.968563-1-richard.henderson@linaro.org> In-Reply-To: <20210723203344.968563-1-richard.henderson@linaro.org> From: Peter Maydell Date: Mon, 26 Jul 2021 13:42:45 +0100 Message-ID: Subject: Re: [PATCH v2 0/3] target/arm: Add sve-default-vector-length cpu property To: Richard Henderson Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2a00:1450:4864:20::632; envelope-from=peter.maydell@linaro.org; helo=mail-ej1-x632.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=ham 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: qemu-arm , QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 23 Jul 2021 at 21:34, Richard Henderson wrote: > > This is intended to resolve #482. > > Changes for v2: > * Split out length bounding fix to new patch. > * Use byte units for sve-default-vector-length. > * Support undocumented -1 "maximum". > * Add documentation. I'm going to apply this to target-arm.next with the following docs tweak squashed into patch 3: diff --git a/docs/system/arm/cpu-features.rst b/docs/system/arm/cpu-features.rst index 4ff36cc83f0..7b97df442aa 100644 --- a/docs/system/arm/cpu-features.rst +++ b/docs/system/arm/cpu-features.rst @@ -379,11 +379,14 @@ example's (1), (4), and (6) exhibit recommended uses of the properties. SVE User-mode Default Vector Length Property -------------------------------------------- -For qemu-aarch64, the cpu property `sve-default-vector-length=N` is +For qemu-aarch64, the cpu property ``sve-default-vector-length=N`` is defined to mirror the Linux kernel parameter file -`/proc/sys/abi/sve_default_vector_length`. The default length, `N`, -is in units of bytes and must be between 16 and 8192. +``/proc/sys/abi/sve_default_vector_length``. The default length, ``N``, +is in units of bytes and must be between 16 and 8192. If not specified, the default vector length is 64. If the default length is larger than the maximum vector length enabled -with `sve` properties, the actual vector length will be reduced. +with ``sve`` properties, the actual vector length will be reduced. + +If this property is set to ``-1`` then the default vector length +is set to the maximum possible length. thanks -- PMM