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=-15.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 A3416C433E0 for ; Wed, 10 Feb 2021 16:05:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 72F9D64E0B for ; Wed, 10 Feb 2021 16:05:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231948AbhBJQEm (ORCPT ); Wed, 10 Feb 2021 11:04:42 -0500 Received: from foss.arm.com ([217.140.110.172]:39946 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232086AbhBJQED (ORCPT ); Wed, 10 Feb 2021 11:04:03 -0500 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 7E0BA113E; Wed, 10 Feb 2021 08:03:16 -0800 (PST) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EE5D83F73B; Wed, 10 Feb 2021 08:03:13 -0800 (PST) Subject: Re: [RFC PATCH v8 5/5] KVM: arm64: ioctl to fetch/store tags in a guest To: Peter Maydell Cc: Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Julien Thierry , Suzuki K Poulose , kvmarm , arm-mail-list , lkml - Kernel Mailing List , Dave Martin , Mark Rutland , Thomas Gleixner , QEMU Developers , Juan Quintela , "Dr. David Alan Gilbert" , Richard Henderson , Haibo Xu , Andrew Jones References: <20210205135803.48321-1-steven.price@arm.com> <20210205135803.48321-6-steven.price@arm.com> From: Steven Price Message-ID: <1e09d70a-1443-c7bd-2d16-f50bc3993a83@arm.com> Date: Wed, 10 Feb 2021 16:03:34 +0000 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; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/02/2021 17:31, Peter Maydell wrote: > On Fri, 5 Feb 2021 at 13:58, Steven Price wrote: >> >> The VMM may not wish to have it's own mapping of guest memory mapped >> with PROT_MTE because this causes problems if the VMM has tag checking >> enabled (the guest controls the tags in physical RAM and it's unlikely >> the tags are correct for the VMM). >> >> Instead add a new ioctl which allows the VMM to easily read/write the >> tags from guest memory, allowing the VMM's mapping to be non-PROT_MTE >> while the VMM can still read/write the tags for the purpose of >> migration. >> >> Signed-off-by: Steven Price >> --- >> arch/arm64/include/uapi/asm/kvm.h | 13 +++++++ >> arch/arm64/kvm/arm.c | 57 +++++++++++++++++++++++++++++++ >> include/uapi/linux/kvm.h | 1 + >> 3 files changed, 71 insertions(+) > > Missing the update to the docs in Documentation/virtual/kvm/api.txt :-) Good point - although I was secretly hoping to get some feedback on the concepts before writing the documentation! But I guess the documentation will help with the review. I'll include some in the next posting. Thanks, Steve