From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f70.google.com (mail-pa0-f70.google.com [209.85.220.70]) by kanga.kvack.org (Postfix) with ESMTP id 2DF9F6B0286 for ; Tue, 15 Nov 2016 09:40:17 -0500 (EST) Received: by mail-pa0-f70.google.com with SMTP id fp5so118500909pac.6 for ; Tue, 15 Nov 2016 06:40:17 -0800 (PST) Received: from NAM01-SN1-obe.outbound.protection.outlook.com (mail-sn1nam01on0083.outbound.protection.outlook.com. [104.47.32.83]) by mx.google.com with ESMTPS id m6si8358509pgg.171.2016.11.15.06.40.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 15 Nov 2016 06:40:16 -0800 (PST) Subject: Re: [RFC PATCH v3 04/20] x86: Handle reduction in physical address size with SME References: <20161110003426.3280.2999.stgit@tlendack-t1.amdoffice.net> <20161110003513.3280.12104.stgit@tlendack-t1.amdoffice.net> <20161115121035.GD24857@8bytes.org> <20161115121456.f4slpk4i2jl3e2ke@pd.tnic> From: Tom Lendacky Message-ID: Date: Tue, 15 Nov 2016 08:40:05 -0600 MIME-Version: 1.0 In-Reply-To: <20161115121456.f4slpk4i2jl3e2ke@pd.tnic> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Borislav Petkov , Joerg Roedel Cc: linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Rik van Riel , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Arnd Bergmann , Jonathan Corbet , Matt Fleming , Konrad Rzeszutek Wilk , Paolo Bonzini , Larry Woodman , Ingo Molnar , Andy Lutomirski , "H. Peter Anvin" , Andrey Ryabinin , Alexander Potapenko , Thomas Gleixner , Dmitry Vyukov On 11/15/2016 6:14 AM, Borislav Petkov wrote: > On Tue, Nov 15, 2016 at 01:10:35PM +0100, Joerg Roedel wrote: >> Maybe add a comment here why you can't use cpu_has (yet). > > So that could be alleviated by moving this function *after* > init_scattered_cpuid_features(). Then you can simply do *cpu_has(). Yes, I can move it after init_scattered_cpuid_features() and then use the cpu_has() function. I'll make sure to include a comment that the function needs to be called after init_scattered_cpuid_features(). > > Also, I'm not sure why we're checking CPUID for the SME feature when we > have sme_get_me_mask() et al which have been setup much earlier... > The feature may be present and enabled even if it is not currently active. In other words, the SYS_CFG MSR bit could be set but we aren't actually using encryption (sme_me_mask is 0). As long as the SYS_CFG MSR bit is set we need to take into account the physical reduction in address space. Thanks, Tom -- 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