From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750953AbdKHH4k (ORCPT ); Wed, 8 Nov 2017 02:56:40 -0500 Received: from mga01.intel.com ([192.55.52.88]:33994 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750720AbdKHH4j (ORCPT ); Wed, 8 Nov 2017 02:56:39 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,363,1505804400"; d="scan'208";a="4988848" 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 0/2] KVM: MMU: fix kvm_is_mmio_pfn() Date: Wed, 8 Nov 2017 15:56:28 +0800 Message-Id: <20171108075630.16991-1-haozhong.zhang@intel.com> X-Mailer: git-send-email 2.14.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some reserved pages, such as those from NVDIMM DAX devices, are not for MMIO, and can be mapped with cached memory type for better performance. However, the above check misconceives those pages as MMIO. Because KVM maps MMIO pages with UC memory type, the performance of guest accesses to those pages would be harmed. Therefore, we check the host memory type in addition and only treat UC/UC- pages as MMIO. Changes in v5: * Rename pat_pfn_is_uc() into pat_pfn_is_uc_or_uc_minus() to avoid confusion. * Drop converters between kvm_pfn_t and pfn_t, because they are not necessary. pat_pfn_is_uc_or_uc_minus() does not need flags in pfn_t, so we can only pass a raw unsigned long to it. Changes in v4: * Mask pfn_t and kvm_pfn_t specific flags in conversion. Changes in v3: * Move cache mode check to pat.c as pat_pfn_is_uc() * Reintroduce converters between kvm_pfn_t and pfn_t. Changes in v2: * Switch to lookup_memtype() to get host memory type. * Rewrite the comment in KVM MMU patch. * Remove v1 patch 2, which is not necessary in v2. Haozhong Zhang (2): x86/mm: add functions to check if a pfn is UC/UC- KVM: MMU: consider host cache mode in MMIO page check arch/x86/include/asm/pat.h | 2 ++ arch/x86/kvm/mmu.c | 15 ++++++++++++++- arch/x86/mm/pat.c | 16 ++++++++++++++++ 3 files changed, 32 insertions(+), 1 deletion(-) -- 2.14.1