From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Lendacky Subject: Re: [RFC PATCH v3 04/20] x86: Handle reduction in physical address size with SME Date: Tue, 15 Nov 2016 08:40:05 -0600 Message-ID: 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> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20161115121456.f4slpk4i2jl3e2ke@pd.tnic> Sender: owner-linux-mm@kvack.org 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 List-Id: linux-efi@vger.kernel.org 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