Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751535AbbGMPUy (ORCPT ); Mon, 13 Jul 2015 11:20:54 -0400 Received: from mga09.intel.com ([134.134.136.24]:46303 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751115AbbGMPUx (ORCPT ); Mon, 13 Jul 2015 11:20:53 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,463,1432623600"; d="scan'208";a="605278218" Message-ID: <55A3D616.8010209@linux.intel.com> Date: Mon, 13 Jul 2015 23:15:34 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Paolo Bonzini , Alex Williamson CC: gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 01/10] KVM: MMU: fix decoding cache type from MTRR References: <1431499348-25188-1-git-send-email-guangrong.xiao@linux.intel.com> <1431499348-25188-2-git-send-email-guangrong.xiao@linux.intel.com> <1436722432.1391.347.camel@redhat.com> <55A2B8F7.1050805@linux.intel.com> <55A36976.6090807@redhat.com> <55A3CEF2.2030200@linux.intel.com> <55A3D57C.4050100@redhat.com> In-Reply-To: <55A3D57C.4050100@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1682 Lines: 54 On 07/13/2015 11:13 PM, Paolo Bonzini wrote: > On 13/07/2015 16:45, Xiao Guangrong wrote: >>> + /* MTRR is completely disabled, use UC for all of physical >>> memory. */ >>> + if (!(mtrr_state->enabled & 0x2)) >>> + return MTRR_TYPE_UNCACHABLE; >>> >>> actually disappears in commit fa61213746a7 (KVM: MTRR: simplify >>> kvm_mtrr_get_guest_memory_type, 2015-06-15). >> >> :( >> >> Based on the SDM, UC is applied to all memory rather than default-type >> if MTRR is disabled. > > There are two issues I think. One is that I cannot find in the current > code that "UC is applied to all memory rather than default-type if MTRR > is disabled". mtrr_default_type unconditionally looks at > mtrr_state->deftype. Yes... Will fix. > >> However, fast boot came back if "return 0xFF" here. So fast boot expects >> that the memory type is WB. > > Yes. > >>> >>> static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state) >>> { >>> if (mtrr_is_enabled(mtrr_state)) >>> return mtrr_state->deftype & >>> IA32_MTRR_DEF_TYPE_TYPE_MASK; >>> else >>> return MTRR_TYPE_UNCACHABLE; >>> } >>> >>> ? Then it's easy to add a quirk that makes the default WRITEBACK until >>> MTRRs are enabled. >> >> It is the wrong configure in OVMF... shall we need to adjust KVM to satisfy >> OVMF? > > That's what quirks are for... The firmware should still be fixed of course. I see, will do it. -- 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/