From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wanpeng Li Subject: Re: [PATCH v3 01/10] KVM: MMU: fix decoding cache type from MTRR Date: Wed, 13 May 2015 16:09:21 +0800 Message-ID: <20150513080920.GA4335@kernel> References: <1431499348-25188-1-git-send-email-guangrong.xiao@linux.intel.com> <1431499348-25188-2-git-send-email-guangrong.xiao@linux.intel.com> Reply-To: Wanpeng Li Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: pbonzini@redhat.com, gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: Xiao Guangrong Return-path: Received: from mga03.intel.com ([134.134.136.65]:44067 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932109AbbEMI1N (ORCPT ); Wed, 13 May 2015 04:27:13 -0400 Content-Disposition: inline In-Reply-To: <1431499348-25188-2-git-send-email-guangrong.xiao@linux.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, May 13, 2015 at 02:42:19PM +0800, Xiao Guangrong wrote: >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 Reviewed-by: Wanpeng Li >--- > 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 kvm" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html