From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9AEAC742A7 for ; Sat, 13 Jul 2019 14:23:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6A7720838 for ; Sat, 13 Jul 2019 14:23:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727848AbfGMOXD (ORCPT ); Sat, 13 Jul 2019 10:23:03 -0400 Received: from mga11.intel.com ([192.55.52.93]:20899 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727504AbfGMOXD (ORCPT ); Sat, 13 Jul 2019 10:23:03 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Jul 2019 07:23:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,486,1557212400"; d="scan'208";a="174701302" Received: from txu2-mobl.ccr.corp.intel.com (HELO [10.255.30.205]) ([10.255.30.205]) by FMSMGA003.fm.intel.com with ESMTP; 13 Jul 2019 07:23:00 -0700 Subject: Re: [PATCH v7 3/3] KVM: vmx: handle vm-exit for UMWAIT and TPAUSE To: Sean Christopherson Cc: pbonzini@redhat.com, rkrcmar@redhat.com, corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, fenghua.yu@intel.com, xiaoyao.li@linux.intel.com, jingqi.liu@intel.com References: <20190712082907.29137-1-tao3.xu@intel.com> <20190712082907.29137-4-tao3.xu@intel.com> <20190712160352.GD29659@linux.intel.com> From: Tao Xu Message-ID: Date: Sat, 13 Jul 2019 22:22:59 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190712160352.GD29659@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/13/2019 12:03 AM, Sean Christopherson wrote: > On Fri, Jul 12, 2019 at 04:29:07PM +0800, Tao Xu wrote: >> --- a/arch/x86/kvm/vmx/nested.c >> +++ b/arch/x86/kvm/vmx/nested.c >> @@ -5213,6 +5213,9 @@ bool nested_vmx_exit_reflected(struct kvm_vcpu *vcpu, u32 exit_reason) >> case EXIT_REASON_ENCLS: >> /* SGX is never exposed to L1 */ >> return false; >> + case EXIT_REASON_UMWAIT: case EXIT_REASON_TPAUSE: > > Grouped case statements are usually stacked vertically, e.g.: > > case EXIT_REASON_UMWAIT: > case EXIT_REASON_TPAUSE: >Ok, thank you for your suggestion. >> + return nested_cpu_has2(vmcs12, >> + SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE); >> default: >> return true; >> } >> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c >> index 0787f140d155..e026b1313dc3 100644 >> --- a/arch/x86/kvm/vmx/vmx.c >> +++ b/arch/x86/kvm/vmx/vmx.c >> @@ -5349,6 +5349,20 @@ static int handle_monitor(struct kvm_vcpu *vcpu) >> return handle_nop(vcpu); >> } >> >> +static int handle_umwait(struct kvm_vcpu *vcpu) >> +{ >> + kvm_skip_emulated_instruction(vcpu); >> + WARN(1, "this should never happen\n"); > > Blech. I'm guessing this code was copy-pasted from handle_xsaves() and > handle_xrstors(). The blurb of "this should never happen" isn't very > helpful, e.g. the WARN itself makes it pretty obvious that we don't expect > to reach this point. WARN_ONCE would also be preferable, no need to spam > the log in the event things go completely haywire. > > Rather than propagate ugly code, what about defining a common helper, e.g. > > static int handle_unexpected_vmexit(struct kvm_vcpu *vcpu) > { > kvm_skip_emulated_instruction(vcpu); > WARN_ONCE(1, "Unexpected VM-Exit = 0x%x", vmcs_read32(VM_EXIT_REASON)); > return 1; > } > > ... > { > [EXIT_REASON_XSAVES] = handle_unexpected_vmexit, > [EXIT_REASON_XRSTORS] = handle_unexpected_vmexit, > > [EXIT_REASON_UMWAIT] = handle_unexpected_vmexit, > [EXIT_REASON_TPAUSE] = handle_unexpected_vmexit, > > } > Thank you Sean, I will do this in next version of patch. >> + return 1; >> +} >> + >> +static int handle_tpause(struct kvm_vcpu *vcpu) >> +{ >> + kvm_skip_emulated_instruction(vcpu); >> + WARN(1, "this should never happen\n"); >> + return 1; >> +} >> + >> static int handle_invpcid(struct kvm_vcpu *vcpu) >> { >> u32 vmx_instruction_info; >> @@ -5559,6 +5573,8 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = { >> [EXIT_REASON_VMFUNC] = handle_vmx_instruction, >> [EXIT_REASON_PREEMPTION_TIMER] = handle_preemption_timer, >> [EXIT_REASON_ENCLS] = handle_encls, >> + [EXIT_REASON_UMWAIT] = handle_umwait, >> + [EXIT_REASON_TPAUSE] = handle_tpause, >> }; >> >> static const int kvm_vmx_max_exit_handlers = >> -- >> 2.20.1 >>