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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B523BC433F5 for ; Sat, 16 Apr 2022 01:32:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0A4EC6B0072; Fri, 15 Apr 2022 21:32:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 054E46B0073; Fri, 15 Apr 2022 21:32:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E5EBB6B0074; Fri, 15 Apr 2022 21:32:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.26]) by kanga.kvack.org (Postfix) with ESMTP id D83FF6B0072 for ; Fri, 15 Apr 2022 21:32:08 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id C7C41120284 for ; Sat, 16 Apr 2022 01:32:08 +0000 (UTC) X-FDA: 79361016336.20.8FE536D Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by imf03.hostedemail.com (Postfix) with ESMTP id 5EE5A20005 for ; Sat, 16 Apr 2022 01:32:07 +0000 (UTC) Received: from dggpemm500021.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4KgFtl21SZzCr3Z; Sat, 16 Apr 2022 09:27:43 +0800 (CST) Received: from dggpemm500014.china.huawei.com (7.185.36.153) by dggpemm500021.china.huawei.com (7.185.36.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 16 Apr 2022 09:32:04 +0800 Received: from [10.174.178.120] (10.174.178.120) by dggpemm500014.china.huawei.com (7.185.36.153) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 16 Apr 2022 09:32:02 +0800 Message-ID: <6de859df-e1c3-e9aa-4530-3b61b9c69a28@huawei.com> Date: Sat, 16 Apr 2022 09:32:01 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH v2 0/9] introduce mirrored memory support for arm64 To: CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , References: <20220414101314.1250667-1-mawupeng1@huawei.com> From: mawupeng In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.178.120] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500014.china.huawei.com (7.185.36.153) X-CFilter-Loop: Reflected Authentication-Results: imf03.hostedemail.com; dkim=none; spf=pass (imf03.hostedemail.com: domain of mawupeng1@huawei.com designates 45.249.212.189 as permitted sender) smtp.mailfrom=mawupeng1@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Stat-Signature: t8tnzdchi9175rxkehoroxejdieab9j5 X-Rspamd-Queue-Id: 5EE5A20005 X-Rspamd-Server: rspam04 X-Rspam-User: X-HE-Tag: 1650072727-967797 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 在 2022/4/14 18:22, Ard Biesheuvel 写道: > On Thu, 14 Apr 2022 at 11:54, Wupeng Ma wrote: >> >> From: Ma Wupeng >> >> Commit b05b9f5f9dcf ("x86, mirror: x86 enabling - find mirrored memory ranges") >> introduced mirrored memory support for x86. This support rely on UEFI to >> report mirrored memory address ranges. See UEFI 2.5 spec pages 157-158: >> >> http://www.uefi.org/sites/default/files/resources/UEFI%202_5.pdf >> >> Memory mirroring is a technique used to separate memory into two separate >> channels, usually on a memory device, like a server. In memory mirroring, >> one channel is copied to another to create redundancy. This method makes >> input/output (I/O) registers and memory appear with more than one address >> range because the same physical byte is accessible at more than one >> address. Using memory mirroring, higher memory reliability and a higher >> level of memory consolidation are possible. >> >> Arm64 can support this too. So mirrored memory support is added to support >> arm64. >> >> Efi_fake_mem is used for testing mirrored features and will not be used in >> production environment. This test features can fake memory's attribute >> values. >> >> The reason why efi_fake_mem support is put first is that memory's attribute >> is reported by BIOS which is hard to simulate. With this support, any arm64 >> machines with efi support can easily test mirrored features. >> >> The main purpose of this patchset is to introduce mirrored support for >> arm64 and we have already fixed the problems we had which is shown in >> patch #5 to patch #7 and try to bring total isolation in patch #8 which >> will disable mirror feature if kernelcore is not specified. >> >> In order to test this support in arm64: >> - patch this patchset >> - add efi_fake_mem=8G@0:0x10000 in kernel parameter to simulate mirrored >> memroy between phy addr 0-8G. >> - add kernelcore=mirror in kernel parameter >> - start you kernel >> > > As I explained before: > > - NAK to EFI fake_mem support on arm64 fake_mem support on arm64 will be removed in subsequent version. > - NAK to the whole series until you come up with a proposal on how to > locate the static kernel image itself into more reliable memory, as > there is really no point to any of this otherwise. Sorry I am not familiar with this, as you metioned before, > you have to iterate over the memory map and look for regions with > the desired attribute, and allocate those pages explicitly. Do you mean this is x86, commit c05cd79750fb ("x86/boot/KASLR: Prefer mirrored memory regions for the kernel physical address"). I will do some research. > I'd prefer to implement this in the bootloader, and only add minimal > logic to the stub to respect the placement of the kernel by the loader > if the loader signals it to do so. Does this bootloader refer to grub and then add minimal logic to arm64-stub.c? What is the loader signal? System exists mirrored memory reported by uefi? Thanks for reviewing, sorry for my ignorance on this. > .