From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-dm6nam11on2059.outbound.protection.outlook.com ([40.107.223.59] helo=NAM11-DM6-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mG0va-002nhq-Or for kexec@lists.infradead.org; Tue, 17 Aug 2021 15:23:02 +0000 Subject: Re: [PATCH v2 03/12] x86/sev: Add an x86 version of prot_guest_has() References: <7d55bac0cf2e73f53816bce3a3097877ed9663f3.1628873970.git.thomas.lendacky@amd.com> <4710eb91-d054-7b31-5106-09e3e54bba9e@amd.com> From: Tom Lendacky Message-ID: Date: Tue, 17 Aug 2021 10:22:52 -0500 In-Reply-To: Content-Language: en-US MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Borislav Petkov Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, iommu@lists.linux-foundation.org, kvm@vger.kernel.org, linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-graphics-maintainer@vmware.com, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, Brijesh Singh , Joerg Roedel , Andi Kleen , Sathyanarayanan Kuppuswamy , Tianyu Lan , Thomas Gleixner , Ingo Molnar , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Joerg Roedel On 8/15/21 9:39 AM, Borislav Petkov wrote: > On Sun, Aug 15, 2021 at 08:53:31AM -0500, Tom Lendacky wrote: >> It's not a cross-vendor thing as opposed to a KVM or other hypervisor >> thing where the family doesn't have to be reported as AMD or HYGON. > > What would be the use case? A HV starts a guest which is supposed to be > encrypted using the AMD's confidential guest technology but the HV tells > the guest that it is not running on an AMD SVM HV but something else? > > Is that even an actual use case? > > Or am I way off? > > I know we have talked about this in the past but this still sounds > insane. Maybe the KVM folks have a better understanding of it... I can change it to be an AMD/HYGON check... although, I'll have to check to see if any (very) early use of the function will work with that. At a minimum, the check in arch/x86/kernel/head64.c will have to be changed or removed. I'll take a closer look. Thanks, Tom > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec