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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C711C433FE for ; Sat, 16 Apr 2022 02:17:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229474AbiDPCT1 (ORCPT ); Fri, 15 Apr 2022 22:19:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229454AbiDPCTA (ORCPT ); Fri, 15 Apr 2022 22:19:00 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A45A93C72F; Fri, 15 Apr 2022 19:16:24 -0700 (PDT) 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > . 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 13BF9C433EF for ; Sat, 16 Apr 2022 01:33:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:CC:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=dYvuDGPF11T022O91+BWsz+HEMNRKL44AFGMVXP61DE=; b=dyVtHSstSlGOkC 1T7JMLaT+PWjD6rY4eP64tfH2AQeMJx+TdrAGGfrkTAHLJ7RaK+syJcUjHzmDIV1XcKEv/tK0df1x 2WESGBS6Hra9jZ/nd6rarfdQ0YdPGvApnrs9xHpgx0wzkKHBDvmGntn/TT1hlWmPfh8e9v7FMI38J A35OWOUBpuES67ecAGUpUQL54lA27b/iIr/WwW3tv5kJ1eYWte7pCRjGneRxijU9YW/J4ULIg4306 0g6f4O4eAIH9SWyrqj2Mc0ca0R9sNI/hcI80FBZVvAzCdNqsdn5cwaKe160tTj6v3IE2Q4URHKM4d ht8+cKDzyCkkD9eR/caw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nfXIU-00BtZ6-D7; Sat, 16 Apr 2022 01:32:22 +0000 Received: from szxga03-in.huawei.com ([45.249.212.189]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nfXIP-00BtX6-B4 for linux-arm-kernel@lists.infradead.org; Sat, 16 Apr 2022 01:32:19 +0000 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: 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220415_183217_759784_C817E4BC X-CRM114-Status: GOOD ( 19.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org CgrlnKggMjAyMi80LzE0IDE4OjIyLCBBcmQgQmllc2hldXZlbCDlhpnpgZM6Cj4gT24gVGh1LCAx NCBBcHIgMjAyMiBhdCAxMTo1NCwgV3VwZW5nIE1hIDxtYXd1cGVuZzFAaHVhd2VpLmNvbT4gd3Jv dGU6Cj4+Cj4+IEZyb206IE1hIFd1cGVuZyA8bWF3dXBlbmcxQGh1YXdlaS5jb20+Cj4+Cj4+IENv bW1pdCBiMDViOWY1ZjlkY2YgKCJ4ODYsIG1pcnJvcjogeDg2IGVuYWJsaW5nIC0gZmluZCBtaXJy b3JlZCBtZW1vcnkgcmFuZ2VzIikKPj4gaW50cm9kdWNlZCBtaXJyb3JlZCBtZW1vcnkgc3VwcG9y dCBmb3IgeDg2LiBUaGlzIHN1cHBvcnQgcmVseSBvbiBVRUZJIHRvCj4+IHJlcG9ydCBtaXJyb3Jl ZCBtZW1vcnkgYWRkcmVzcyByYW5nZXMuICBTZWUgVUVGSSAyLjUgc3BlYyBwYWdlcyAxNTctMTU4 Ogo+Pgo+PiAgICBodHRwOi8vd3d3LnVlZmkub3JnL3NpdGVzL2RlZmF1bHQvZmlsZXMvcmVzb3Vy Y2VzL1VFRkklMjAyXzUucGRmCj4+Cj4+IE1lbW9yeSBtaXJyb3JpbmcgaXMgYSB0ZWNobmlxdWUg dXNlZCB0byBzZXBhcmF0ZSBtZW1vcnkgaW50byB0d28gc2VwYXJhdGUKPj4gY2hhbm5lbHMsIHVz dWFsbHkgb24gYSBtZW1vcnkgZGV2aWNlLCBsaWtlIGEgc2VydmVyLiBJbiBtZW1vcnkgbWlycm9y aW5nLAo+PiBvbmUgY2hhbm5lbCBpcyBjb3BpZWQgdG8gYW5vdGhlciB0byBjcmVhdGUgcmVkdW5k YW5jeS4gVGhpcyBtZXRob2QgbWFrZXMKPj4gaW5wdXQvb3V0cHV0IChJL08pIHJlZ2lzdGVycyBh bmQgbWVtb3J5IGFwcGVhciB3aXRoIG1vcmUgdGhhbiBvbmUgYWRkcmVzcwo+PiByYW5nZSBiZWNh dXNlIHRoZSBzYW1lIHBoeXNpY2FsIGJ5dGUgaXMgYWNjZXNzaWJsZSBhdCBtb3JlIHRoYW4gb25l Cj4+IGFkZHJlc3MuIFVzaW5nIG1lbW9yeSBtaXJyb3JpbmcsIGhpZ2hlciBtZW1vcnkgcmVsaWFi aWxpdHkgYW5kIGEgaGlnaGVyCj4+IGxldmVsIG9mIG1lbW9yeSBjb25zb2xpZGF0aW9uIGFyZSBw b3NzaWJsZS4KPj4KPj4gQXJtNjQgY2FuIHN1cHBvcnQgdGhpcyB0b28uIFNvIG1pcnJvcmVkIG1l bW9yeSBzdXBwb3J0IGlzIGFkZGVkIHRvIHN1cHBvcnQKPj4gYXJtNjQuCj4+Cj4+IEVmaV9mYWtl X21lbSBpcyB1c2VkIGZvciB0ZXN0aW5nIG1pcnJvcmVkIGZlYXR1cmVzIGFuZCB3aWxsIG5vdCBi ZSB1c2VkIGluCj4+IHByb2R1Y3Rpb24gZW52aXJvbm1lbnQuIFRoaXMgdGVzdCBmZWF0dXJlcyBj YW4gZmFrZSBtZW1vcnkncyBhdHRyaWJ1dGUKPj4gdmFsdWVzLgo+Pgo+PiBUaGUgcmVhc29uIHdo eSBlZmlfZmFrZV9tZW0gc3VwcG9ydCBpcyBwdXQgZmlyc3QgaXMgdGhhdCBtZW1vcnkncyBhdHRy aWJ1dGUKPj4gaXMgcmVwb3J0ZWQgYnkgQklPUyB3aGljaCBpcyBoYXJkIHRvIHNpbXVsYXRlLiBX aXRoIHRoaXMgc3VwcG9ydCwgYW55IGFybTY0Cj4+IG1hY2hpbmVzIHdpdGggZWZpIHN1cHBvcnQg Y2FuIGVhc2lseSB0ZXN0IG1pcnJvcmVkIGZlYXR1cmVzLgo+Pgo+PiBUaGUgbWFpbiBwdXJwb3Nl IG9mIHRoaXMgcGF0Y2hzZXQgaXMgdG8gaW50cm9kdWNlIG1pcnJvcmVkIHN1cHBvcnQgZm9yCj4+ IGFybTY0IGFuZCB3ZSBoYXZlIGFscmVhZHkgZml4ZWQgdGhlIHByb2JsZW1zIHdlIGhhZCB3aGlj aCBpcyBzaG93biBpbgo+PiBwYXRjaCAjNSB0byBwYXRjaCAjNyBhbmQgdHJ5IHRvIGJyaW5nIHRv dGFsIGlzb2xhdGlvbiBpbiBwYXRjaCAjOCB3aGljaAo+PiB3aWxsIGRpc2FibGUgbWlycm9yIGZl YXR1cmUgaWYga2VybmVsY29yZSBpcyBub3Qgc3BlY2lmaWVkLgo+Pgo+PiBJbiBvcmRlciB0byB0 ZXN0IHRoaXMgc3VwcG9ydCBpbiBhcm02NDoKPj4gLSBwYXRjaCB0aGlzIHBhdGNoc2V0Cj4+IC0g YWRkIGVmaV9mYWtlX21lbT04R0AwOjB4MTAwMDAgaW4ga2VybmVsIHBhcmFtZXRlciB0byBzaW11 bGF0ZSBtaXJyb3JlZAo+PiAgICBtZW1yb3kgYmV0d2VlbiBwaHkgYWRkciAwLThHLgo+PiAtIGFk ZCBrZXJuZWxjb3JlPW1pcnJvciBpbiBrZXJuZWwgcGFyYW1ldGVyCj4+IC0gc3RhcnQgeW91IGtl cm5lbAo+Pgo+IAo+IEFzIEkgZXhwbGFpbmVkIGJlZm9yZToKPiAKPiAtIE5BSyB0byBFRkkgZmFr ZV9tZW0gc3VwcG9ydCBvbiBhcm02NAoKZmFrZV9tZW0gc3VwcG9ydCBvbiBhcm02NCB3aWxsIGJl IHJlbW92ZWQgaW4gc3Vic2VxdWVudCB2ZXJzaW9uLgoKPiAtIE5BSyB0byB0aGUgd2hvbGUgc2Vy aWVzIHVudGlsIHlvdSBjb21lIHVwIHdpdGggYSBwcm9wb3NhbCBvbiBob3cgdG8KPiBsb2NhdGUg dGhlIHN0YXRpYyBrZXJuZWwgaW1hZ2UgaXRzZWxmIGludG8gbW9yZSByZWxpYWJsZSBtZW1vcnks IGFzCj4gdGhlcmUgaXMgcmVhbGx5IG5vIHBvaW50IHRvIGFueSBvZiB0aGlzIG90aGVyd2lzZS4K ClNvcnJ5IEkgYW0gbm90IGZhbWlsaWFyIHdpdGggdGhpcywgYXMgeW91IG1ldGlvbmVkIGJlZm9y ZSwKCiA+IHlvdSBoYXZlIHRvIGl0ZXJhdGUgb3ZlciB0aGUgbWVtb3J5IG1hcCBhbmQgbG9vayBm b3IgcmVnaW9ucyB3aXRoCiA+IHRoZSBkZXNpcmVkIGF0dHJpYnV0ZSwgYW5kIGFsbG9jYXRlIHRo b3NlIHBhZ2VzIGV4cGxpY2l0bHkuCgpEbyB5b3UgbWVhbiB0aGlzIGlzIHg4NiwgY29tbWl0IGMw NWNkNzk3NTBmYgooIng4Ni9ib290L0tBU0xSOiBQcmVmZXIgbWlycm9yZWQgbWVtb3J5IHJlZ2lv bnMgZm9yIHRoZSBrZXJuZWwgcGh5c2ljYWwgYWRkcmVzcyIpLgpJIHdpbGwgZG8gc29tZSByZXNl YXJjaC4KCiA+IEknZCBwcmVmZXIgdG8gaW1wbGVtZW50IHRoaXMgaW4gdGhlIGJvb3Rsb2FkZXIs IGFuZCBvbmx5IGFkZCBtaW5pbWFsCiA+IGxvZ2ljIHRvIHRoZSBzdHViIHRvIHJlc3BlY3QgdGhl IHBsYWNlbWVudCBvZiB0aGUga2VybmVsIGJ5IHRoZSBsb2FkZXIKID4gaWYgdGhlIGxvYWRlciBz aWduYWxzIGl0IHRvIGRvIHNvLgoKRG9lcyB0aGlzIGJvb3Rsb2FkZXIgcmVmZXIgdG8gZ3J1YiBh bmQgdGhlbiBhZGQgbWluaW1hbCBsb2dpYyB0byBhcm02NC1zdHViLmM/CgpXaGF0IGlzIHRoZSBs b2FkZXIgc2lnbmFsPwpTeXN0ZW0gZXhpc3RzIG1pcnJvcmVkIG1lbW9yeSByZXBvcnRlZCBieSB1 ZWZpPwoKVGhhbmtzIGZvciByZXZpZXdpbmcsIHNvcnJ5IGZvciBteSBpZ25vcmFuY2Ugb24gdGhp cy4KCj4gLgoKCgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X18KbGludXgtYXJtLWtlcm5lbCBtYWlsaW5nIGxpc3QKbGludXgtYXJtLWtlcm5lbEBsaXN0cy5p bmZyYWRlYWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGluZm8v bGludXgtYXJtLWtlcm5lbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 From: mawupeng Date: Sat, 16 Apr 2022 01:32:01 +0000 Subject: Re: [PATCH v2 0/9] introduce mirrored memory support for arm64 Message-Id: <6de859df-e1c3-e9aa-4530-3b61b9c69a28@huawei.com> List-Id: References: <20220414101314.1250667-1-mawupeng1@huawei.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: ardb@kernel.org Cc: akpm@linux-foundation.org, catalin.marinas@arm.com, will@kernel.org, corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zyccr.com, dvhart@infradead.org, andy@infradead.org, rppt@kernel.org, paulmck@kernel.org, peterz@infradead.org, jroedel@suse.de, songmuchun@bytedance.com, macro@orcam.me.uk, frederic@kernel.org, W_Armin@gmx.de, john.garry@huawei.com, seanjc@google.com, tsbogend@alpha.franken.de, anshuman.khandual@arm.com, chenhuacai@kernel.org, david@redhat.com, gpiccoli@igalia.com, mark.rutland@arm.com, wangkefeng.wang@huawei.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org, linux-ia64@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-mm@kvack.org 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. > .