Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933474AbbEMGuM (ORCPT ); Wed, 13 May 2015 02:50:12 -0400 Received: from mga03.intel.com ([134.134.136.65]:13162 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753585AbbEMGqC (ORCPT ); Wed, 13 May 2015 02:46:02 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,419,1427785200"; d="scan'208";a="492939044" From: Xiao Guangrong To: pbonzini@redhat.com Cc: gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Xiao Guangrong Subject: [PATCH v3 01/10] KVM: MMU: fix decoding cache type from MTRR Date: Wed, 13 May 2015 14:42:19 +0800 Message-Id: <1431499348-25188-2-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1431499348-25188-1-git-send-email-guangrong.xiao@linux.intel.com> References: <1431499348-25188-1-git-send-email-guangrong.xiao@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2138 Lines: 64 There are some bugs in current get_mtrr_type(); 1: bit 1 of mtrr_state->enabled is corresponding bit 11 of IA32_MTRR_DEF_TYPE MSR which completely control MTRR's enablement that means other bits are ignored if it is cleared 2: the fixed MTRR ranges are controlled by bit 0 of mtrr_state->enabled (bit 10 of IA32_MTRR_DEF_TYPE) 3: if MTRR is disabled, UC is applied to all of physical memory rather than mtrr_state->def_type Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index b78e83f..d00cebd 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2393,19 +2393,20 @@ EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page); static int get_mtrr_type(struct mtrr_state_type *mtrr_state, u64 start, u64 end) { - int i; u64 base, mask; u8 prev_match, curr_match; - int num_var_ranges = KVM_NR_VAR_MTRR; + int i, num_var_ranges = KVM_NR_VAR_MTRR; - if (!mtrr_state->enabled) - return 0xFF; + /* MTRR is completely disabled, use UC for all of physical memory. */ + if (!(mtrr_state->enabled & 0x2)) + return MTRR_TYPE_UNCACHABLE; /* Make end inclusive end, instead of exclusive */ end--; /* Look in fixed ranges. Just return the type as per start */ - if (mtrr_state->have_fixed && (start < 0x100000)) { + if (mtrr_state->have_fixed && (mtrr_state->enabled & 0x1) && + (start < 0x100000)) { int idx; if (start < 0x80000) { @@ -2428,9 +2429,6 @@ static int get_mtrr_type(struct mtrr_state_type *mtrr_state, * Look of multiple ranges matching this address and pick type * as per MTRR precedence */ - if (!(mtrr_state->enabled & 2)) - return mtrr_state->def_type; - prev_match = 0xFF; for (i = 0; i < num_var_ranges; ++i) { unsigned short start_state, end_state; -- 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/