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=unavailable 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 157E0C742CA for ; Fri, 12 Jul 2019 16:03:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDE22206B8 for ; Fri, 12 Jul 2019 16:03:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727147AbfGLQDy (ORCPT ); Fri, 12 Jul 2019 12:03:54 -0400 Received: from mga18.intel.com ([134.134.136.126]:36561 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726907AbfGLQDx (ORCPT ); Fri, 12 Jul 2019 12:03:53 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Jul 2019 09:03:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,483,1557212400"; d="scan'208";a="174485411" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.165]) by FMSMGA003.fm.intel.com with ESMTP; 12 Jul 2019 09:03:52 -0700 Date: Fri, 12 Jul 2019 09:03:52 -0700 From: Sean Christopherson To: Tao Xu 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 Subject: Re: [PATCH v7 3/3] KVM: vmx: handle vm-exit for UMWAIT and TPAUSE Message-ID: <20190712160352.GD29659@linux.intel.com> References: <20190712082907.29137-1-tao3.xu@intel.com> <20190712082907.29137-4-tao3.xu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190712082907.29137-4-tao3.xu@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Archived-At: List-Archive: List-Post: 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: > + 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, } > + 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 >