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=-5.3 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 E7BB1C433DF for ; Wed, 5 Aug 2020 17:01:55 +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 B04C322D00 for ; Wed, 5 Aug 2020 17:01:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="QJWu+y9m" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B04C322D00 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]:58340 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k3Mnb-0004z0-1X for qemu-devel@archiver.kernel.org; Wed, 05 Aug 2020 13:01:55 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59954) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k3Mmf-0004Kb-QZ for qemu-devel@nongnu.org; Wed, 05 Aug 2020 13:00:57 -0400 Received: from mail-pg1-x530.google.com ([2607:f8b0:4864:20::530]:46760) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1k3Mmd-0005ox-7t for qemu-devel@nongnu.org; Wed, 05 Aug 2020 13:00:57 -0400 Received: by mail-pg1-x530.google.com with SMTP id p8so8670266pgn.13 for ; Wed, 05 Aug 2020 10:00:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=osJ2w+V9cZlk83KQovNCzTBOfhPvNCOTBe1WQBXex7o=; b=QJWu+y9m3V7SE1wNRsLdIEHCSbwHUOmovMOGk1xgsWBXwXlPgNp01Ck0/Pp3BF/1rT Rz1Aifm3/6rwqZn2vnRm2nbceCH/lSZqgTJmm6q8sOiRvYFIBiKyqUliTgV9hb6M4atE oAfZQ+1nMnZgGX1fC01D+kM4GaPWR1fxvwhqcX/otcGYmda6FriZLedzij5P8UY3CzjA zceJHJedwakQbyz6+iA7c5gcngg5swvVpRRRakOXKXtiZEijoFUrJVjYIS6WJMxxEtJM fDzgcpFFHPA87G8BHm3GdQ8mIwXs4ZRO7DPTFE3IdVBCzi5c5DBo/DQF8g9ieWNMHdoJ sRSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=osJ2w+V9cZlk83KQovNCzTBOfhPvNCOTBe1WQBXex7o=; b=jWIlLV718P/ZY4AC0c41Xep3aEwNGSfY+6KxjiYYhM1uj48p58Vfs73xfPPPd+oNNk q6jM9trY50hdBC3T2sxY8kvsbl1kFu1O+p3pstSzghPsJWCYMNHRrtQvpQh1OsWbGnuX QQQfVIJfmU2Pl68f2H1Jk89QCbP62fo+KekaDh2ICtnuthom4s7ZJYSTBjoqPcyMooWu ccVSqt3frcD47VvEDafi3m7hrCY14xEWLmU0qkgkc4nP+LysbL/mrLPgpt/Q0qAXfa/Y 6jDM1OKTP+ae84PTQHJPs1m2JKcz4yW1JFfx3vKHXEh7xXdnbQLH+gf+H/+ner5gMEiM nHaw== X-Gm-Message-State: AOAM530QKxxtcs9YxoOdKNe1rINzzXfcWs2PXMDHWcb3Zi2SZGdZhC+3 ztv2MxWTq0IhdT2jBmXka9QMcQ== X-Google-Smtp-Source: ABdhPJzQJ/EEfJRsmkRFPU+9t4B/n7GFyI6EDFDgoU+ZATPvv8T+BiowXtEPbDo9LUMhJ2p2XFDcgg== X-Received: by 2002:a62:1c0f:: with SMTP id c15mr4114148pfc.235.1596646852800; Wed, 05 Aug 2020 10:00:52 -0700 (PDT) Received: from [192.168.1.11] ([71.212.141.89]) by smtp.gmail.com with ESMTPSA id 193sm4022388pfu.169.2020.08.05.10.00.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 05 Aug 2020 10:00:52 -0700 (PDT) Subject: Re: v8.1M cpu emulation and target-arm feature-identification strategy To: Peter Maydell , =?UTF-8?Q?Alex_Benn=c3=a9e?= References: <2c5ed9d8-6d79-1b53-5588-8fb9efebf0fa@linaro.org> <87tuxhkpo2.fsf@linaro.org> From: Richard Henderson Message-ID: Date: Wed, 5 Aug 2020 10:00:50 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::530; envelope-from=richard.henderson@linaro.org; helo=mail-pg1-x530.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. 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: qemu-arm , QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 8/5/20 9:52 AM, Peter Maydell wrote: > On Wed, 5 Aug 2020 at 17:45, Alex Bennée wrote: >> I wouldn't test other feature bits but what stopping us adding: >> >> struct ARMISARegisters { >> uint32_t id_isar0; >> ... >> uint64_t id_aa64dfr1; >> /* >> * The following are synthetic flags for features not exposed to >> * the directly exposed to the guest but needed by QEMU's >> * feature detection. >> */ >> bool v81m_lob; >> } isar; > > Nothing, except we already have a set of synthetic flags, that's > what the ARM_FEATURE_* are... > >> That said we still seem to have a number of ARM_FEATURE flags, are we >> hoping they all go away eventually? > > I think that they're a mixed bag. Some represent cleanups we > haven't got round to doing yet (eg ARM_FEATURE_NEON, which would > be a fair chunk of work, or ARM_FEATURE_PXN which would be pretty > trivial to change to looking at ID_MMFR0.VMSA >=4). Some are > features that pre-date the ID feature bit scheme and so might > be awkward to convert (eg ARM_FEATURE_XSCALE). One or two > we've already converted and just forgot to take out of the > enum (eg ARM_FEATURE_CRC)... I've always assumed we'd never get rid of all of them. Older ones like XSCALE are obvious, but I don't think there's a clear indicator for V{5,6,7,8} either. r~