From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f198.google.com (mail-io0-f198.google.com [209.85.223.198]) by kanga.kvack.org (Postfix) with ESMTP id 69B696B0038 for ; Thu, 4 May 2017 10:13:44 -0400 (EDT) Received: by mail-io0-f198.google.com with SMTP id f102so16899393ioi.7 for ; Thu, 04 May 2017 07:13:44 -0700 (PDT) Received: from NAM03-DM3-obe.outbound.protection.outlook.com (mail-dm3nam03on0053.outbound.protection.outlook.com. [104.47.41.53]) by mx.google.com with ESMTPS id n6si324184otn.130.2017.05.04.07.13.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 04 May 2017 07:13:43 -0700 (PDT) Subject: Re: [PATCH v5 31/32] x86: Add sysfs support for Secure Memory Encryption References: <20170418211612.10190.82788.stgit@tlendack-t1.amdoffice.net> <20170418212212.10190.73484.stgit@tlendack-t1.amdoffice.net> <1498ec98-b19d-c47d-902b-a68870a3f860@intel.com> <20170427072547.GB15297@dhcp-128-65.nay.redhat.com> From: Tom Lendacky Message-ID: <2abc7ad8-9d64-8617-44fe-1cb8af31e1f6@amd.com> Date: Thu, 4 May 2017 09:13:35 -0500 MIME-Version: 1.0 In-Reply-To: <20170427072547.GB15297@dhcp-128-65.nay.redhat.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dave Young , Dave Hansen 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, Thomas Gleixner , Rik van Riel , Brijesh Singh , Toshimitsu Kani , Arnd Bergmann , Jonathan Corbet , Matt Fleming , Joerg Roedel , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Konrad Rzeszutek Wilk , Andrey Ryabinin , Ingo Molnar , "Michael S. Tsirkin" , Andy Lutomirski , "H. Peter Anvin" , Borislav Petkov , Paolo Bonzini , Alexander Potapenko , Larry Woodman , Dmitry Vyukov On 4/27/2017 2:25 AM, Dave Young wrote: > On 04/21/17 at 02:55pm, Dave Hansen wrote: >> On 04/18/2017 02:22 PM, Tom Lendacky wrote: >>> Add sysfs support for SME so that user-space utilities (kdump, etc.) can >>> determine if SME is active. >>> >>> A new directory will be created: >>> /sys/kernel/mm/sme/ >>> >>> And two entries within the new directory: >>> /sys/kernel/mm/sme/active >>> /sys/kernel/mm/sme/encryption_mask >> >> Why do they care, and what will they be doing with this information? > > Since kdump will copy old memory but need this to know if the old memory > was encrypted or not. With this sysfs file we can know the previous SME > status and pass to kdump kernel as like a kernel param. > > Tom, have you got chance to try if it works or not? Sorry, I haven't had a chance to test this yet. Thanks, Tom > > Thanks > Dave > -- 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