From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751949AbdJRLHH (ORCPT ); Wed, 18 Oct 2017 07:07:07 -0400 Received: from mga09.intel.com ([134.134.136.24]:61608 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751683AbdJRLHG (ORCPT ); Wed, 18 Oct 2017 07:07:06 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.43,396,1503385200"; d="scan'208";a="324602209" From: "Kang, Luwei" To: Paolo Bonzini , "kvm@vger.kernel.org" CC: "rkrcmar@redhat.com" , "tglx@linutronix.de" , "mingo@redhat.com" , "hpa@zytor.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Chao Peng Subject: RE: [PATCH 0/9] Intel Processor Trace virtulization enabling Thread-Topic: [PATCH 0/9] Intel Processor Trace virtulization enabling Thread-Index: AQHTRuraeeq7WYE40EGyCTYR5nADyaLnbqgAgAHyv9D//4L7gIAAjZhg Date: Wed, 18 Oct 2017 11:06:48 +0000 Message-ID: <82D7661F83C1A047AF7DC287873BF1E167E1B74A@SHSMSX101.ccr.corp.intel.com> References: <1508155781-4576-1-git-send-email-luwei.kang@intel.com> <66f40c86-cdf3-84a7-6d42-c0c7f6850e19@redhat.com> <82D7661F83C1A047AF7DC287873BF1E167E1B5FB@SHSMSX101.ccr.corp.intel.com> <0ca0d53b-640a-c124-08dc-dbf009e01a8e@redhat.com> In-Reply-To: <0ca0d53b-640a-c124-08dc-dbf009e01a8e@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ctpclassification: CTP_IC x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiMmM4ZTA0MTEtM2E5OS00ZTI4LWFiNTgtYmI5MmFlYWQ3MzRhIiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjIuNS4xOCIsIlRydXN0ZWRMYWJlbEhhc2giOiJ1RnRIc29BNEo4MG9vU1J5WkFGSjBqRDhEMGRzVFZKNDh2eXhiWmRtZ2Q4TldQMFBLZWg1Y3BwNlZZWmw1YnkxIn0= dlp-product: dlpe-windows dlp-version: 11.0.0.116 dlp-reaction: no-action x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id v9IB7DbV012907 > >> Nested virtualization is interesting. We would like the nested > >> hypervisor to be forced to set the "use GPA for processor tracing" > >> secondary execution control whenever "enable EPT" is set and RTIT_CTL > >> is nonzero. There is no way to encode that in > >> IA32_VMX_PROCBASED_CTLS2, however. It would be nice if Intel could > >> reserve a bit in IA32_VMX_EPT_VPID_CAP for KVM to express that > >> constraint. > > > > Do you mean if nested hypervisor get the capability of "Guest PT use > > GPA" and EPT has enable. Highly recommend nested hypervisor set " > > Guest PT use GPA " as well. > > Well, it's required more than recommended. However, it's only required if "enable EPT" is set and RTIT_CTL is nonzero. > > > If nested hypervisor is also KVM, "use GPA for processor tracing" > > will be set for sure. But other hypervisor may not do that. So, we'd > > better add a flag in IA32_VMX_EPT_VPID_CAP to express that constraint. > > Correct. The constraint would be: > > * RTIT_CTL on entry is zero if EPT is disabled > > * RTIT_CTL on entry is zero if EPT is enabled and "Guest PT uses GPA" is zero > > Maybe IA32_VMX_EPT_VPID_CAP is not the best place. I'll let Intel decide that. > Get it. I have feedback to hardware architect. I hope it can be applied but it may need wait a long time. Thanks, Luwei Kang