From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751277AbeEDKYG (ORCPT ); Fri, 4 May 2018 06:24:06 -0400 Received: from mga18.intel.com ([134.134.136.126]:44141 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750733AbeEDKYE (ORCPT ); Fri, 4 May 2018 06:24:04 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,362,1520924400"; d="scan'208";a="221592089" Date: Fri, 4 May 2018 13:23:58 +0300 From: Alexander Shishkin To: Luwei Kang Cc: kvm@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, pbonzini@redhat.com, rkrcmar@redhat.com, linux-kernel@vger.kernel.org, joro@8bytes.org, peterz@infradead.org, chao.p.peng@linux.intel.com Subject: Re: [PATCH v7 13/13] KVM: x86: Disable Intel Processor Trace when VMXON in L1 guest Message-ID: <20180504102358.eojiggqrnhxng2ru@um.fi.intel.com> References: <1525349323-9938-1-git-send-email-luwei.kang@intel.com> <1525349323-9938-14-git-send-email-luwei.kang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1525349323-9938-14-git-send-email-luwei.kang@intel.com> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 03, 2018 at 08:08:43PM +0800, Luwei Kang wrote: > Currently, Intel Processor Trace do not support tracing in L1 guest > VMX operation(IA32_VMX_MISC[bit 14] is 0). As mentioned in SDM, I don't understand this patch. You mention VMX_MISC[14] here, but I can't see anything related to it in the code. Also, the description should probably say "...does not support tracing in VMX *if* IA32_VMX_MISC[bit 14] is 0." > on these type of processors, execution of the VMXON instruction will > clears IA32_RTIT_CTL.TraceEn and any attempt to write IA32_RTIT_CTL > causes a general-protection exception (#GP). > > Signed-off-by: Luwei Kang > --- > arch/x86/kvm/vmx.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index c125fb1..1e800d0 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -3952,7 +3952,8 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > break; > case MSR_IA32_RTIT_CTL: > if ((pt_mode != PT_MODE_HOST_GUEST) || > - vmx_rtit_ctl_check(vcpu, data)) > + vmx_rtit_ctl_check(vcpu, data) || > + vmx->nested.vmxon) > return 1; > vmcs_write64(GUEST_IA32_RTIT_CTL, data); > pt_set_intercept_for_msr(vmx, !(data & RTIT_CTL_TRACEEN)); > @@ -8029,6 +8030,12 @@ static int handle_vmon(struct kvm_vcpu *vcpu) > if (ret) > return ret; > > + if (pt_mode == PT_MODE_HOST_GUEST) { > + vmx->pt_desc.guest.ctl = 0; > + vmcs_write64(GUEST_IA32_RTIT_CTL, 0); > + pt_set_intercept_for_msr(vmx, 1); > + } > + > nested_vmx_succeed(vcpu); > return kvm_skip_emulated_instruction(vcpu); > } > -- > 1.8.3.1 >