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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 394B4C64E7B for ; Tue, 1 Dec 2020 14:44:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D13802076C for ; Tue, 1 Dec 2020 14:44:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ICa9ez6x" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391698AbgLAOod (ORCPT ); Tue, 1 Dec 2020 09:44:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48350 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391697AbgLAOod (ORCPT ); Tue, 1 Dec 2020 09:44:33 -0500 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D56D9C0613D6 for ; Tue, 1 Dec 2020 06:43:52 -0800 (PST) Received: by mail-wr1-x441.google.com with SMTP id t4so2957802wrr.12 for ; Tue, 01 Dec 2020 06:43:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=JIA0Scl4OIMMkSS/5dfb1RixGjs/UhotRuHwz308dGA=; b=ICa9ez6xKvXoVFd5a+nyt9V7db40a6UDXltW3gu+5eDTPPoS7Y+JHn0qhh505cto8f GRLJkOPi8X4qfWqafWsQ6KrEg1FBVyXFnMuueku5Rvh2nAkHFVLVmB94DGc7SMapcND8 iCfVQkWismF7cf9Pxzp3Pi5NrsRfBnkClOAt3axQ3sGSRNPGhXQv7qFGz5pajfx4cjxn 5vFpF4gkJTjJGtnvbwVNxH5lm7Jc0cCZfd9IXPiS4SNeZVCufI98odvCCzyskxTIRMwx S+gz72PQ6q5hfrC4mBZr8J/bOiuIbHPAIKUX5idfyO8GKJNpNm3oeMe1COzvBl6m/a3D I85A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=JIA0Scl4OIMMkSS/5dfb1RixGjs/UhotRuHwz308dGA=; b=ib5SIO+zIIO2pklUZf2EAvFVHxHNODOMOUywSGmanGVA13bk5O2pjEEGxTIhTLPPI7 yts1CLriU4EfU04u5vKOb6YVq98IlCqIf0aObtZ7DFPd1RfMeS8pOUZ6kVeSX0wt3IoG 9KraEN5lbO8mFqK7Q/MOVs8QI5fb1CtA6q99Ivy43bX35X0RHA8l154K/6H+QZEemAlW uVVRxXzTduM+QZFWwYrEjujolmJ50W5adDmphJbVsmfBjClg+Qh8F+/MUWTnj9J7ZgGB U0w9FE2lVDvYcal3reLdqOPNk/VwP/6HgsgU/AmZwdgmhQY0sPiiX8QKmCfIqwOomW5s VD4w== X-Gm-Message-State: AOAM531y9Ah2+wNO6fS2tHcf+7taASEwow616YpwAMz11eqFVA1MPfrL J/8etlMOdXCs0kyXPBOShjV6ng== X-Google-Smtp-Source: ABdhPJxFvoIa6LKNTCZysKjYl0L3o6ekKKdzC32vTURn5ckCGb5MJxfK027unJvURm7vUyFNvUoRNg== X-Received: by 2002:a5d:4e87:: with SMTP id e7mr4467528wru.70.1606833831387; Tue, 01 Dec 2020 06:43:51 -0800 (PST) Received: from google.com ([2a01:4b00:8523:2d03:7c5f:5ab5:ac1f:89ce]) by smtp.gmail.com with ESMTPSA id y130sm99756wmc.22.2020.12.01.06.43.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Dec 2020 06:43:50 -0800 (PST) Date: Tue, 1 Dec 2020 14:43:49 +0000 From: David Brazdil To: Mark Rutland Cc: Sudeep Holla , kvmarm@lists.cs.columbia.edu, Jonathan Corbet , Catalin Marinas , Will Deacon , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , Dennis Zhou , Tejun Heo , Christoph Lameter , Lorenzo Pieralisi , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel-team@android.com Subject: Re: [PATCH v3 06/23] kvm: arm64: Add kvm-arm.protected early kernel parameter Message-ID: <20201201144349.bglz7yicc3peixe6@google.com> References: <20201126155421.14901-1-dbrazdil@google.com> <20201126155421.14901-7-dbrazdil@google.com> <20201127163254.zxdrszlveaxhluwn@bogus> <20201201131913.u7m2eifvtus74dra@google.com> <20201201140734.GA86881@C02TD0UTHF1T.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201201140734.GA86881@C02TD0UTHF1T.local> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org > > > be just me, but if you agree please update so that it doesn't give remote > > > idea that it is not valid on VHE enabled hardware. > > > > > > I was trying to run this on the hardware and was trying to understand the > > > details on how to do that. > > > > I see what you're saying, but !CONFIG_ARM64_VHE isn't accurate either. The > > option makes sense if: > > 1) all cores booted in EL2 > > == is_hyp_mode_available() > > 2) ID_AA64MMFR1_EL1.VH=0 or !CONFIG_ARM64_VHE > > == !is_kernel_in_hyp_mode() > > > > The former feels implied for KVM, the latter could be 'Valid if the kernel > > is running in EL1'? WDYT? > > I reckon we can avoid the restriction if we instead add an early stub > like with have for KASLR. That way we could parse the command line > early, and if necessary re-initialize EL2 and drop to EL1 before the > main kernel has to make any decisions about how to initialize things. > That would allow us to have a more general kvm-arm.mode option where a > single kernel Image could support: > > * "protected" mode on nVHE or VHE HW > * "nvhe" mode on nVHE or VHE HW > * "vhe" mode on VHE HW > > ... defaulting to VHE/nVHE modes depending on HW support. > > That would also be somewhat future-proof if we have to add other > variants of protected mode in future, as we could extend the mode option > with parameters for each mode. Agreed that 'mode' is a more future-proof flag and I would very much love to have an option to force nVHE on VHE HW. I however expect that the early stub would not be a trivial addition and would not want to get into that in this series. Could we agree on 'protected' as the only supported value for the time being? David