From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id 3C44B831F4 for ; Thu, 18 May 2017 13:02:02 -0400 (EDT) Received: by mail-wm0-f71.google.com with SMTP id d127so10115129wmf.15 for ; Thu, 18 May 2017 10:02:02 -0700 (PDT) Received: from mail.skyhub.de (mail.skyhub.de. [5.9.137.197]) by mx.google.com with ESMTP id q4si6630326wrb.303.2017.05.18.10.02.00 for ; Thu, 18 May 2017 10:02:01 -0700 (PDT) Date: Thu, 18 May 2017 19:01:53 +0200 From: Borislav Petkov Subject: Re: [PATCH v5 31/32] x86: Add sysfs support for Secure Memory Encryption Message-ID: <20170518170153.eqiyat5s6q3yeejl@pd.tnic> References: <20170418211612.10190.82788.stgit@tlendack-t1.amdoffice.net> <20170418212212.10190.73484.stgit@tlendack-t1.amdoffice.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170418212212.10190.73484.stgit@tlendack-t1.amdoffice.net> Sender: owner-linux-mm@kvack.org List-ID: To: Tom Lendacky 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 , Radim =?utf-8?B?S3LEjW3DocWZ?= , Toshimitsu Kani , Arnd Bergmann , Jonathan Corbet , Matt Fleming , "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 On Tue, Apr 18, 2017 at 04:22:12PM -0500, Tom Lendacky wrote: > Add sysfs support for SME so that user-space utilities (kdump, etc.) can > determine if SME is active. But why do user-space tools need to know that? I mean, when we load the kdump kernel, we do it with the first kernel, with the kexec_load() syscall, AFAICT. And that code does a lot of things during that init, like machine_kexec_prepare()->init_pgtable() to prepare the ident mapping of the second kernel, for example. What I'm aiming at is that the first kernel knows *exactly* whether SME is enabled or not and doesn't need to tell the second one through some sysfs entries - it can do that during loading. So I don't think we need any userspace things at all... Or? -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply. -- 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