From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751159AbdKHH4w (ORCPT ); Wed, 8 Nov 2017 02:56:52 -0500 Received: from mga01.intel.com ([192.55.52.88]:4953 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750960AbdKHH4q (ORCPT ); Wed, 8 Nov 2017 02:56:46 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,363,1505804400"; d="scan'208";a="1241320357" From: Haozhong Zhang To: kvm@vger.kernel.org, x86@kernel.org Cc: linux-kernel@vger.kernel.org, Paolo Bonzini , rkrcmar@redhat.com, Xiao Guangrong , Dan Williams , ivan.d.cuevas.escareno@intel.com, karthik.kumar@intel.com, Konrad Rzeszutek Wilk , Olif Chapman , Mikulas Patocka , Haozhong Zhang , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Borislav Petkov , Tom Lendacky Subject: [PATCH v5 1/2] x86/mm: add a function to check if a pfn is UC/UC- Date: Wed, 8 Nov 2017 15:56:29 +0800 Message-Id: <20171108075630.16991-2-haozhong.zhang@intel.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20171108075630.16991-1-haozhong.zhang@intel.com> References: <20171108075630.16991-1-haozhong.zhang@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It will be used by KVM to check whether a pfn should be mapped to guest as UC. Signed-off-by: Haozhong Zhang --- arch/x86/include/asm/pat.h | 2 ++ arch/x86/mm/pat.c | 16 ++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/arch/x86/include/asm/pat.h b/arch/x86/include/asm/pat.h index fffb2794dd89..fabb0cf00e77 100644 --- a/arch/x86/include/asm/pat.h +++ b/arch/x86/include/asm/pat.h @@ -21,4 +21,6 @@ int io_reserve_memtype(resource_size_t start, resource_size_t end, void io_free_memtype(resource_size_t start, resource_size_t end); +bool pat_pfn_is_uc_or_uc_minus(unsigned long pfn); + #endif /* _ASM_X86_PAT_H */ diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index fe7d57a8fb60..e1282dd4eeb8 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -677,6 +677,22 @@ static enum page_cache_mode lookup_memtype(u64 paddr) return rettype; } +/** + * Check with PAT whether the memory type of a pfn is UC or UC-. + * + * Only to be called when PAT is enabled. + * + * Returns true, if the memory type of @pfn is UC or UC-. + * Otherwise, returns false. + */ +bool pat_pfn_is_uc_or_uc_minus(unsigned long pfn) +{ + enum page_cache_mode cm = lookup_memtype(PFN_PHYS(pfn)); + + return cm == _PAGE_CACHE_MODE_UC || cm == _PAGE_CACHE_MODE_UC_MINUS; +} +EXPORT_SYMBOL_GPL(pat_pfn_is_uc_or_uc_minus); + /** * io_reserve_memtype - Request a memory type mapping for a region of memory * @start: start (physical address) of the region -- 2.14.1