From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Lendacky Subject: Re: [PATCH v5 31/32] x86: Add sysfs support for Secure Memory Encryption Date: Fri, 26 May 2017 10:47:39 -0500 Message-ID: References: <20170418211612.10190.82788.stgit@tlendack-t1.amdoffice.net> <20170418212212.10190.73484.stgit@tlendack-t1.amdoffice.net> <20170518170153.eqiyat5s6q3yeejl@pd.tnic> <20170526024933.GA3228@dhcp-128-65.nay.redhat.com> <5927B767.3010701@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5927B767.3010701@redhat.com> Sender: owner-linux-mm@kvack.org To: xlpang@redhat.com, Dave Young , Borislav Petkov Cc: linux-efi@vger.kernel.org, Brijesh Singh , Toshimitsu Kani , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Matt Fleming , x86@kernel.org, linux-mm@kvack.org, Alexander Potapenko , "H. Peter Anvin" , Larry Woodman , linux-arch@vger.kernel.org, kvm@vger.kernel.org, Jonathan Corbet , Joerg Roedel , linux-doc@vger.kernel.org, kasan-dev@googlegroups.com, Ingo Molnar , Andrey Ryabinin , Rik van Riel , Arnd Bergmann , Konrad Rzeszutek Wilk , Andy Lutomirski , Thomas Gleixner , Dmitry Vyukov , kexec@lists.infradead.org, linux-kernel@vger.kernel.or List-Id: linux-efi@vger.kernel.org On 5/26/2017 12:04 AM, Xunlei Pang wrote: > On 05/26/2017 at 10:49 AM, Dave Young wrote: >> Ccing Xunlei he is reading the patches see what need to be done for >> kdump. There should still be several places to handle to make kdump work. >> >> On 05/18/17 at 07:01pm, Borislav Petkov wrote: >>> 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... >> If kdump kernel can get the SME status from hardware register then this >> should be not necessary and this patch can be dropped. > > Yes, I also agree with dropping this one. Consensus is to drop, so it will be. Thanks, Tom > > Regards, > Xunlei > -- 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