From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752500AbdK3M1J (ORCPT ); Thu, 30 Nov 2017 07:27:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43022 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751099AbdK3M1H (ORCPT ); Thu, 30 Nov 2017 07:27:07 -0500 Subject: Re: [PATCH v3 9/9] KVM: x86: Implement Intel Processor Trace context switch To: Luwei Kang , kvm@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, rkrcmar@redhat.com, linux-kernel@vger.kernel.org, joro@8bytes.org, Chao Peng References: <1511814242-12949-1-git-send-email-luwei.kang@intel.com> <1511814242-12949-10-git-send-email-luwei.kang@intel.com> From: Paolo Bonzini Message-ID: <39ef8b45-f6f2-9002-259a-a6d0fa1058fc@redhat.com> Date: Thu, 30 Nov 2017 13:27:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1511814242-12949-10-git-send-email-luwei.kang@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Thu, 30 Nov 2017 12:27:07 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/11/2017 21:24, Luwei Kang wrote: > + if (pt_mode == PT_MODE_HOST_GUEST) { > + u32 eax, ebx, ecx, edx; > + > + cpuid_count(0x14, 1, &eax, &ebx, &ecx, &edx); Since it's used in many places, it's better if you cache CPUID[14,1].EAX. Thanks, Paolo > + memset(&vmx->pt_desc, 0, sizeof(vmx->pt_desc)); > + vmx->pt_desc.addr_num = eax & 0x7; > + /* Bit[6~0] are forced to 1, writes are ignored. */ > + vmx->pt_desc.guest.output_mask = 0x7F; > + vmcs_write64(GUEST_IA32_RTIT_CTL, 0); > + }