From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id BF5206B0397 for ; Thu, 27 Apr 2017 03:26:08 -0400 (EDT) Received: by mail-qt0-f197.google.com with SMTP id u30so6150016qtu.14 for ; Thu, 27 Apr 2017 00:26:08 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id k16si2028412qtc.216.2017.04.27.00.26.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Apr 2017 00:26:07 -0700 (PDT) Date: Thu, 27 Apr 2017 15:25:47 +0800 From: Dave Young Subject: Re: [PATCH v5 31/32] x86: Add sysfs support for Secure Memory Encryption Message-ID: <20170427072547.GB15297@dhcp-128-65.nay.redhat.com> References: <20170418211612.10190.82788.stgit@tlendack-t1.amdoffice.net> <20170418212212.10190.73484.stgit@tlendack-t1.amdoffice.net> <1498ec98-b19d-c47d-902b-a68870a3f860@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1498ec98-b19d-c47d-902b-a68870a3f860@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Tom Lendacky , 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 , Radim =?utf-8?B?S3LEjW3DocWZ?= , 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 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? 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