From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f69.google.com (mail-it0-f69.google.com [209.85.214.69]) by kanga.kvack.org (Postfix) with ESMTP id 36F2C6B0279 for ; Fri, 26 May 2017 12:22:43 -0400 (EDT) Received: by mail-it0-f69.google.com with SMTP id q81so10258558itc.9 for ; Fri, 26 May 2017 09:22:43 -0700 (PDT) Received: from NAM01-SN1-obe.outbound.protection.outlook.com (mail-sn1nam01on0077.outbound.protection.outlook.com. [104.47.32.77]) by mx.google.com with ESMTPS id 79si1216974ior.125.2017.05.26.09.22.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 26 May 2017 09:22:42 -0700 (PDT) Subject: Re: [PATCH v5 17/32] x86/mm: Add support to access boot related data in the clear References: <20170418211612.10190.82788.stgit@tlendack-t1.amdoffice.net> <20170418211921.10190.1537.stgit@tlendack-t1.amdoffice.net> <20170515183517.mb4k2gp2qobbuvtm@pd.tnic> <20170518195051.GA5651@codeblueprint.co.uk> From: Tom Lendacky Message-ID: <4c2ef3ba-2940-3330-d362-5b2b0d812c6f@amd.com> Date: Fri, 26 May 2017 11:22:36 -0500 MIME-Version: 1.0 In-Reply-To: <20170518195051.GA5651@codeblueprint.co.uk> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Matt Fleming , Borislav Petkov Cc: linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Rik van Riel , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Toshimitsu Kani , Arnd Bergmann , Jonathan Corbet , "Michael S. Tsirkin" , Joerg Roedel , Konrad Rzeszutek Wilk , Paolo Bonzini , Larry Woodman , Brijesh Singh , Ingo Molnar , Andy Lutomirski , "H. Peter Anvin" , Andrey Ryabinin , Alexander Potapenko , Dave Young , Thomas Gleixner , Dmitry Vyukov , Ard Biesheuvel On 5/18/2017 2:50 PM, Matt Fleming wrote: > On Mon, 15 May, at 08:35:17PM, Borislav Petkov wrote: >> On Tue, Apr 18, 2017 at 04:19:21PM -0500, Tom Lendacky wrote: >> >>> + paddr = boot_params.efi_info.efi_memmap_hi; >>> + paddr <<= 32; >>> + paddr |= boot_params.efi_info.efi_memmap; >>> + if (phys_addr == paddr) >>> + return true; >>> + >>> + paddr = boot_params.efi_info.efi_systab_hi; >>> + paddr <<= 32; >>> + paddr |= boot_params.efi_info.efi_systab; >> >> So those two above look like could be two global vars which are >> initialized somewhere in the EFI init path: >> >> efi_memmap_phys and efi_systab_phys or so. >> >> Matt ? >> >> And then you won't need to create that paddr each time on the fly. I >> mean, it's not a lot of instructions but still... > > We should already have the physical memmap address available in > 'efi.memmap.phys_map'. Unfortunately memremap_is_efi_data() is called before the efi structure gets initialized, so I can't use that value. > > And the physical address of the system table should be in > 'efi_phys.systab'. See efi_init(). In addition to the same issue as efi.memmap.phys_map, efi_phys has the __initdata attribute so it will be released/freed which will cause problems in checks performed afterwards. Thanks, Tom > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org