From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id 7DCD72806EA for ; Thu, 20 Apr 2017 13:07:04 -0400 (EDT) Received: by mail-wr0-f200.google.com with SMTP id c55so6224169wrc.22 for ; Thu, 20 Apr 2017 10:07:04 -0700 (PDT) Received: from mail.skyhub.de (mail.skyhub.de. [2a01:4f8:190:11c2::b:1457]) by mx.google.com with ESMTP id n89si3085802wmi.41.2017.04.20.10.07.02 for ; Thu, 20 Apr 2017 10:07:03 -0700 (PDT) Date: Thu, 20 Apr 2017 18:59:22 +0200 From: Borislav Petkov Subject: Re: [PATCH v5 05/32] x86/CPU/AMD: Handle SME reduction in physical address size Message-ID: <20170420165922.j2inlwbchrs6senw@pd.tnic> References: <20170418211612.10190.82788.stgit@tlendack-t1.amdoffice.net> <20170418211711.10190.30861.stgit@tlendack-t1.amdoffice.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170418211711.10190.30861.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 04:17:11PM -0500, Tom Lendacky wrote: > When System Memory Encryption (SME) is enabled, the physical address > space is reduced. Adjust the x86_phys_bits value to reflect this > reduction. > > Signed-off-by: Tom Lendacky > --- > arch/x86/kernel/cpu/amd.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) ... > @@ -622,8 +624,14 @@ static void early_init_amd(struct cpuinfo_x86 *c) > > /* Check if SME is enabled */ > rdmsrl(MSR_K8_SYSCFG, msr); > - if (!(msr & MSR_K8_SYSCFG_MEM_ENCRYPT)) > + if (msr & MSR_K8_SYSCFG_MEM_ENCRYPT) { > + unsigned int ebx; > + > + ebx = cpuid_ebx(0x8000001f); > + c->x86_phys_bits -= (ebx >> 6) & 0x3f; > + } else { > clear_cpu_cap(c, X86_FEATURE_SME); > + } Lemme do some simplifying to save an indent level, get rid of local var ebx and kill some { }-brackets for a bit better readability: if (c->extended_cpuid_level >= 0x8000001f) { u64 msr; if (!cpu_has(c, X86_FEATURE_SME)) return; /* Check if SME is enabled */ rdmsrl(MSR_K8_SYSCFG, msr); if (msr & MSR_K8_SYSCFG_MEM_ENCRYPT) c->x86_phys_bits -= (cpuid_ebx(0x8000001f) >> 6) & 0x3f; else clear_cpu_cap(c, X86_FEATURE_SME); } -- 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