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 ADD66C43334 for ; Sat, 11 Jun 2022 09:56:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229994AbiFKJ42 (ORCPT ); Sat, 11 Jun 2022 05:56:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229541AbiFKJ41 (ORCPT ); Sat, 11 Jun 2022 05:56:27 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08B6BEE15; Sat, 11 Jun 2022 02:56:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 965DA60BA3; Sat, 11 Jun 2022 09:56:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF641C3411E; Sat, 11 Jun 2022 09:56:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654941386; bh=G3SijAZJFwW8PPbomjAxbmJ1C1Qf1Qf77wWOoRRw+dg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=je5xCyBasUps0lw+zm8BT+55x7BMo8QBuhxo7JbtlactdaXmHz6lygNzLVrkm8nAX HjEppJFc+QzCFrtWjpMbQ5TNT070wVV+inQya2B9+gtBdLCpCi5lhYrB8oioVSA00t hIu1Oa3GrD0WLeAPrt7UP5jlkYHkU2fo87dm0Y2tsE2pbKenH7urJXTDUAgrXYtoWI sACEfm3Hy0H/485yd2z03sytvQHGo5HqeAr0OHZgDGtUHNS7u3v0z9DoUqRmcgnTGS yJ2Edt+EBxtqLD6Zk4/TW4K+j7AB4xUoNv3rGt0AT9EmLHGsWZAuNEVqCOGQlFxuD6 6hRDH3YDodvdQ== Date: Sat, 11 Jun 2022 12:56:12 +0300 From: Mike Rapoport To: Ard Biesheuvel Cc: Wupeng Ma , Andrew Morton , Jonathan Corbet , Will Deacon , Catalin Marinas , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , X86 ML , "H. Peter Anvin" , Darren Hart , Andy Shevchenko , Paul Walmsley , Palmer Dabbelt , Albert Ou , "Paul E. McKenney" , Kees Cook , songmuchun@bytedance.com, Randy Dunlap , damien.lemoal@opensource.wdc.com, Stephen Boyd , Wei Liu , Robin Murphy , David Hildenbrand , Anshuman Khandual , Zhen Lei , Kefeng Wang , gpiccoli@igalia.com, Huacai Chen , Geert Uytterhoeven , chenzhou10@huawei.com, vijayb@linux.microsoft.com, Linux Doc Mailing List , Linux Kernel Mailing List , Linux ARM , linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v3 0/6] introduce mirrored memory support for arm64 Message-ID: References: <20220607093805.1354256-1-mawupeng1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Fri, Jun 10, 2022 at 01:23:34PM +0200, Ard Biesheuvel wrote: > On Tue, 7 Jun 2022 at 11:16, 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. > > > > These EFI memory regions have various attributes, and the "mirrored" > > attribute is one of them. The physical memory region whose descriptors > > in EFI memory map has EFI_MEMORY_MORE_RELIABLE attribute (bit: 16) are > > mirrored. The address range mirroring feature of the kernel arranges such > > mirrored regions into normal zones and other regions into movable zones. > > > > Arm64 can support this too. So mirrored memory support is added to support > > arm64. > > > > The main purpose of this patch set is to introduce mirrored support for > > arm64 and we have already fixed the problems we had which is shown in > > patch #5 to patch #8 and try to bring total isolation in patch #9 which > > will disable mirror feature if kernelcore is not specified. > > > > In order to test this support in arm64: > > - patch this patch set > > - add kernelcore=mirror in kernel parameter > > - start you kernel > > > > Patch #1-#2 introduce mirrored memory support form arm64. > > Patch #3-#5 fix some bugs for arm64 if memory reliable is enabled. > > Patch #6 disable mirror feature if kernelcore is not specified. > > > > Thanks to Ard Biesheuvel's hard work [1], now kernel will perfer mirrored > > memory if kaslr is enabled. > > > > [1] https://lore.kernel.org/linux-arm-kernel/CAMj1kXEPVEzMgOM4+Yj6PxHA-jFuDOAUdDJSiSxy_XaP4P7LSw@mail.gmail.com/T/ > > > > Changelog since v2: > > - remove efi_fake_mem support > > - remove Commit ("remove some redundant code in ia64 efi_init") since > > efi_print_memmap() is not public > > - add mirror flag back on initrd memory > > > > Changelog since v1: > > - update changelog in cover letter > > - use PHYS_PFN in patch #7 > > > > Ma Wupeng (6): > > efi: Make efi_find_mirror() public > > arm64/mirror: arm64 enabling - find mirrored memory ranges > > mm: Ratelimited mirrored memory related warning messages > > mm: Demote warning message in vmemmap_verify() to debug level > > mm: Add mirror flag back on initrd memory > > efi: Disable mirror feature if kernelcore is not specified > > > > I have tested these changes on QEMU/arm64 with the patch below, and > things seem to work as expected. We have some minor issues to work out > but the general shape of this code is good. > > As for the mm/ changes: does anyone mind if I take those through the > EFI tree as well? No objections from me. > I don't think the EFI and -mm changes depend on each other, so they > can go into -mm separately as well. -- Sincerely yours, Mike.