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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 DBEE6C352BE for ; Fri, 17 Apr 2020 09:39:33 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 6C5B3208E4 for ; Fri, 17 Apr 2020 09:39:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C5B3208E4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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 E8D4D4B24B; Fri, 17 Apr 2020 05:39:31 -0400 (EDT) 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 7zWDwBe2Vwgr; Fri, 17 Apr 2020 05:39:30 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id CF3164B257; Fri, 17 Apr 2020 05:39:30 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id F20794B24B for ; Fri, 17 Apr 2020 05:39:29 -0400 (EDT) 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 CMXupwY1afGZ for ; Fri, 17 Apr 2020 05:39:28 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mm01.cs.columbia.edu (Postfix) with ESMTP id CDFC54B14A for ; Fri, 17 Apr 2020 05:39:28 -0400 (EDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 60F2F30E; Fri, 17 Apr 2020 02:39:28 -0700 (PDT) Received: from [10.37.12.128] (unknown [10.37.12.128]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7D2C23F73D; Fri, 17 Apr 2020 02:39:26 -0700 (PDT) Subject: Re: [PATCH 3/8] arm64: cpufeature: Add CPU capability for AArch32 EL1 support To: maz@kernel.org References: <20200414213114.2378-1-will@kernel.org> <20200414213114.2378-4-will@kernel.org> <20200415101444.GC12621@willie-the-truck> <7978a5a9-463e-5e96-7ea9-d8472b7b051c@arm.com> <20200415142237.651114f7@why> From: Suzuki K Poulose Message-ID: <1ffdf91a-e418-61ec-1056-756e1a81f4a6@arm.com> Date: Fri, 17 Apr 2020 10:44:16 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20200415142237.651114f7@why> Content-Language: en-US Cc: saiprakash.ranjan@codeaurora.org, kernel-team@android.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, dianders@chromium.org, will@kernel.org, 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 04/15/2020 02:22 PM, Marc Zyngier wrote: > On Wed, 15 Apr 2020 14:15:51 +0100 > Suzuki K Poulose wrote: > >> On 04/15/2020 11:14 AM, Will Deacon wrote: >>> On Wed, Apr 15, 2020 at 11:13:54AM +0100, Suzuki K Poulose wrote: >>>> On 04/14/2020 10:31 PM, Will Deacon wrote: >>>>> Although we emit a "SANITY CHECK" warning and taint the kernel if we >>>>> detect a CPU mismatch for AArch32 support at EL1, we still online the >>>>> CPU with disastrous consequences for any running 32-bit VMs. >>>>> >>>>> Introduce a capability for AArch32 support at EL1 so that late onlining >>>>> of incompatible CPUs is forbidden. >>>>> >>>>> Signed-off-by: Will Deacon >>>> >>>> One of the other important missing sanity check for KVM is the VMID width >>>> check. I will code something up. >>> >>> Cheers! Do we handle things like the IPA size already? >> >> Good point. No, we don't. I will include this too. > > There is also the question of the ARMv8.5-GTG extension. I have a patch > that treats it as non-strict, but that approach would fail with KVM if > we online a late CPU without support for the right page size at S2. Good point. Again this can be added to the list of checks performed on the hot-plugged CPUs along with IPA, VMID width. Cheers Suzuki _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm