Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751269AbbHEEKM (ORCPT ); Wed, 5 Aug 2015 00:10:12 -0400 Received: from mga14.intel.com ([192.55.52.115]:49562 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750742AbbHEEKK (ORCPT ); Wed, 5 Aug 2015 00:10:10 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,613,1432623600"; d="scan'208";a="742410588" From: Xiao Guangrong To: pbonzini@redhat.com Cc: gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, ru.pchel@gmail.com, Xiao Guangrong Subject: [PATCH v2 0/9] KVM: MMU: fix and improve validation of mmio page fault Date: Wed, 5 Aug 2015 12:04:18 +0800 Message-Id: <1438747467-25425-1-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 2.1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2961 Lines: 73 Changelog in v2: - rename reset_*_rsvds_bits_mask() to reset_*_zero_bits_mask() and is_shadow_rsvd_bits_set() to is_shadow_zero_bits_set() to better match what we are checking. Thanks for Paolo's suggestion. Current code validating mmio #PF is buggy, it was spotted by Pavel Shirshov, the bug is that qemu complained with "KVM: unknown exit, hardware reason 31" and KVM shown these info: [84245.284948] EPT: Misconfiguration. [84245.285056] EPT: GPA: 0xfeda848 [84245.285154] ept_misconfig_inspect_spte: spte 0x5eaef50107 level 4 [84245.285344] ept_misconfig_inspect_spte: spte 0x5f5fadc107 level 3 [84245.285532] ept_misconfig_inspect_spte: spte 0x5141d18107 level 2 [84245.285723] ept_misconfig_inspect_spte: spte 0x52e40dad77 level 1 This is because we got a mmio #PF and the handler see the mmio spte becomes normal (points to the ram page) However, this is valid after introducing fast mmio spte invalidation which increases the generation-number instead of zapping mmio sptes, a example is as follows: 1. QEMU drops mmio region by adding a new memslot 2. invalidate all mmio sptes 3. VCPU 0 VCPU 1 access the invalid mmio spte access the region originally was MMIO before set the spte to the normal ram map mmio #PF check the spte and see it becomes normal ram mapping !!! The first patch simply fixes the bug by dropping the validation in mmio handler which is good for backport Later patches enable fully check reserved bits for shadow page table entries, since shadow page table and guest page table have the some format, this patches reuse the logic which checks reserved bits on guest pte to check sptes In order to catching as many bugs as possible, we not only check the reserved bits on hardware but also check other bits that spte never used Xiao Guangrong (9): KVM: MMU: fix validation of mmio page fault KVM: MMU: move FNAME(is_rsvd_bits_set) to mmu.c KVM: MMU: introduce rsvd_bits_validate KVM: MMU: split reset_rsvds_bits_mask KVM: MMU: split reset_rsvds_bits_mask_ept KVM: MMU: introduce the framework to check zero bits on sptes KVM: MMU: introduce is_shadow_zero_bits_set() KVM: MMU: fully check zero bits for sptes KVM: VMX: drop ept misconfig check arch/x86/include/asm/kvm_host.h | 16 ++- arch/x86/kvm/mmu.c | 283 ++++++++++++++++++++++++---------------- arch/x86/kvm/mmu.h | 4 +- arch/x86/kvm/paging_tmpl.h | 13 +- arch/x86/kvm/svm.c | 1 + arch/x86/kvm/vmx.c | 74 +---------- arch/x86/kvm/x86.c | 3 +- 7 files changed, 193 insertions(+), 201 deletions(-) -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/