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=-3.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 E14D5C2D0DB for ; Mon, 20 Jan 2020 11:56:47 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 76E5B2087E for ; Mon, 20 Jan 2020 11:56:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="yypSpKZT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 76E5B2087E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 0DB2A4AEF6; Mon, 20 Jan 2020 06:56:47 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@kernel.org Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id sCV-taN7jTgI; Mon, 20 Jan 2020 06:56:42 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 66EF64AEF1; Mon, 20 Jan 2020 06:56:42 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id B79A94AEB8 for ; Mon, 20 Jan 2020 06:56:41 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id xkz0QoMfRbAB for ; Mon, 20 Jan 2020 06:56:37 -0500 (EST) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 5EBAC4AEB2 for ; Mon, 20 Jan 2020 06:56:37 -0500 (EST) Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4270D207FF; Mon, 20 Jan 2020 11:56:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579521396; bh=G5BjgiERIPgD2gmhgW49sz0utTOoaFQGf9Xe0v3nM94=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=yypSpKZTEYdwkcQzZT7E8+v22pWxs9mENCsNX0pUqHTAnjRfPEDL2pRw9TL5bPvs6 lSYkudo8DfYGo8c5fI59pA4t1YAm6JyJolJVeH3r+wvItyzkWoraMiulpKysfuyB9h UGJHcoUZ3LzYQd5sjyKCJzW5BajPqZHbGEpp7QXI= Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1itVfW-000Fp6-Hy; Mon, 20 Jan 2020 11:56:34 +0000 MIME-Version: 1.0 Date: Mon, 20 Jan 2020 12:56:34 +0100 From: Marc Zyngier To: Vladimir Murzin Subject: Re: [PATCH] ARM: virt: Relax arch timer version check during early boot In-Reply-To: <38a43fed-1c7a-69ea-3662-e17f13ca74d6@arm.com> References: <1579097798-106243-1-git-send-email-vladimir.murzin@arm.com> <38a43fed-1c7a-69ea-3662-e17f13ca74d6@arm.com> Message-ID: <55fbdb33fc3e107385c12def941aa934@kernel.org> X-Sender: maz@kernel.org User-Agent: Roundcube Webmail/1.3.8 X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: vladimir.murzin@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On 2020-01-20 12:34, Vladimir Murzin wrote: > Hi Marc, > > On 1/20/20 11:14 AM, Marc Zyngier wrote: >> Hi Vladimir, >> >> On 2020-01-20 11:46, Vladimir Murzin wrote: >>> + Marc >>> + kvmarm@lists.cs.columbia.edu >>> >>> On 1/15/20 2:16 PM, Vladimir Murzin wrote: >>>> Updates to the Generic Timer architecture allow ID_PFR1.GenTimer to >>>> have values other than 0 or 1. At the moment, Linux is quite strict >>>> in >>>> the way it handles this field at early boot and will not configure >>>> arch timer if it doesn't find the value 1. >>>> >>>> Since here use ubfx for arch timer version extraction (hyb-stub >>>> build >>>> with -march=armv7-a, so it is safe) >>>> >>>> To help backports (even though the code was correct at the time of >>>> writing) >>>> Fixes: 8ec58be9f3ff ("ARM: virt: arch_timers: enable access to >>>> physical timers") >>>> Signed-off-by: Vladimir Murzin >> >> I'm not opposed to such a change, but it'd be good to document what >> other values >> are expected here, as the current (Rev E_a) ARM ARM only mentions >> values 0 and 1. > > That true, ARM ARM doesn't mention it yet. OTOH, should we really care > about exact values as soon it stays compatible? That's for you to say, really. But given that you hint at some changes, it'd be good to have at least a short sentence explaining that, for example, "upcoming revisions of the architecture will allow different ID_PFR1.GenTimer values while preserving backward compatibility". Other than that, feel free to add my Acked-by: Marc Zyngier Thanks, M. -- Jazz is not dead. It just smells funny... _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm