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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,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 91127C352A5 for ; Mon, 10 Feb 2020 15:46:20 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 3250D20842 for ; Mon, 10 Feb 2020 15:46:20 +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="Nbgh66A2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3250D20842 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 C076F4A4F7; Mon, 10 Feb 2020 10:46:19 -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 qj2W0dRuF6UQ; Mon, 10 Feb 2020 10:46:18 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id B25324A650; Mon, 10 Feb 2020 10:46:18 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E4B1E4A4FC for ; Mon, 10 Feb 2020 10:46:16 -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 3zkP4PYf1mlx for ; Mon, 10 Feb 2020 10:46:16 -0500 (EST) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id F2EAB4A4F7 for ; Mon, 10 Feb 2020 10:46:15 -0500 (EST) Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (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 53B6620733; Mon, 10 Feb 2020 15:46:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581349574; bh=TTGiUvb9RHz3hdhmJfOzp0KIapqFPLU42O9zSWvHhOE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Nbgh66A2RBEWvXx6MerEIUd9giZyvTUtyT0g89HKzIxi8UAO5FFSC3DotkWGBZgWh 8VmqH2A4GRYx8VmqwMzWPYlvCHE9g4TRJiKoqXV66JFgqs70vggQKyGjqiH94fc6A/ x27HEPnRKKPuNUTsEcUCTryiOPmjdOg06CwR+Wdo= Date: Mon, 10 Feb 2020 15:46:08 +0000 From: Will Deacon To: Marc Zyngier Subject: Re: [RFC PATCH 0/5] Removing support for 32bit KVM/arm host Message-ID: <20200210154608.GA21086@willie-the-truck> References: <20200210141324.21090-1-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200210141324.21090-1-maz@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Cc: Anders Berg , Russell King , Arnd Bergmann , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Paolo Bonzini , kvmarm@lists.cs.columbia.edu 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Mon, Feb 10, 2020 at 02:13:19PM +0000, Marc Zyngier wrote: > KVM/arm was merged just over 7 years ago, and has lived a very quiet > life so far. It mostly works if you're prepared to deal with its > limitations, it has been a good prototype for the arm64 version, > but it suffers a few problems: > > - It is incomplete (no debug support, no PMU) > - It hasn't followed any of the architectural evolutions > - It has zero users (I don't count myself here) I tend to use it to test that it still works, but that's it. > - It is more and more getting in the way of new arm64 developments To echo this last point, we're currently looking at the possibility of using KVM to isolate VMs from the host in Android. The scope of the changes we think we'll have to make would mean effectively duplicating the existing code for 32-bit or implementing a whole load of unused and untested functionality to keep the current structure. Neither of these options are particularly satisfactory from a maintainance point of view, so removing the 32-bit code if it doesn't have any significant use would be welcomed: Acked-by: Will Deacon Will _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm