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=-7.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, HK_RANDOM_FROM,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 E78ADC54FD0 for ; Fri, 24 Apr 2020 13:28:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE0F820656 for ; Fri, 24 Apr 2020 13:28:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727788AbgDXN26 (ORCPT ); Fri, 24 Apr 2020 09:28:58 -0400 Received: from mga09.intel.com ([134.134.136.24]:55893 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726301AbgDXN25 (ORCPT ); Fri, 24 Apr 2020 09:28:57 -0400 IronPort-SDR: 2s/wr26Nd3cLiGALaelVfs8niM8JAi7yMdAixrqfniPydWDoLg96CjXhREObewCT9q0JcBKxaU dgzjpltsgThw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Apr 2020 06:28:57 -0700 IronPort-SDR: T9TGNZ54+4RZ2ioaL6az2UD8ZULfAOjgf9lrqoLaQX+kQKpbELXNz5hZj51kFieA0tC6sPCris yUedWC3CkNtQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,311,1583222400"; d="scan'208";a="403298479" Received: from xiaoyaol-mobl.ccr.corp.intel.com (HELO [10.249.173.189]) ([10.249.173.189]) by orsmga004.jf.intel.com with ESMTP; 24 Apr 2020 06:28:54 -0700 Subject: Re: [RFC PATCH 1/3] kvm: x86: Rename KVM_DEBUGREG_RELOAD to KVM_DEBUGREG_NEED_RELOAD To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, Nadav Amit , Vitaly Kuznetsov , linux-kernel@vger.kernel.org References: <20200416101509.73526-1-xiaoyao.li@intel.com> <20200416101509.73526-2-xiaoyao.li@intel.com> <20200423190941.GN17824@linux.intel.com> From: Xiaoyao Li Message-ID: Date: Fri, 24 Apr 2020 21:28:53 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200423190941.GN17824@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 4/24/2020 3:09 AM, Sean Christopherson wrote: > On Thu, Apr 16, 2020 at 06:15:07PM +0800, Xiaoyao Li wrote: >> To make it more clear that the flag means DRn (except DR7) need to be >> reloaded before vm entry. >> >> Signed-off-by: Xiaoyao Li >> --- >> arch/x86/include/asm/kvm_host.h | 2 +- >> arch/x86/kvm/x86.c | 6 +++--- >> 2 files changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >> index c7da23aed79a..f465c76e6e5a 100644 >> --- a/arch/x86/include/asm/kvm_host.h >> +++ b/arch/x86/include/asm/kvm_host.h >> @@ -511,7 +511,7 @@ struct kvm_pmu_ops; >> enum { >> KVM_DEBUGREG_BP_ENABLED = 1, >> KVM_DEBUGREG_WONT_EXIT = 2, >> - KVM_DEBUGREG_RELOAD = 4, >> + KVM_DEBUGREG_NEED_RELOAD = 4, > > My vote would be for KVM_DEBUGREG_DIRTY Any bit that is set switch_db_regs > triggers a reload, whereas I would expect a RELOAD flag to be set _every_ > time a load is needed and thus be the only bit that's checked > That's what I intended to do with this series, apparently I failed it. :( >> }; >> >> struct kvm_mtrr_range { >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index de77bc9bd0d7..cce926658d10 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -1067,7 +1067,7 @@ static void kvm_update_dr0123(struct kvm_vcpu *vcpu) >> if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) { >> for (i = 0; i < KVM_NR_DB_REGS; i++) >> vcpu->arch.eff_db[i] = vcpu->arch.db[i]; >> - vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD; >> + vcpu->arch.switch_db_regs |= KVM_DEBUGREG_NEED_RELOAD; >> } >> } >> >> @@ -8407,7 +8407,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) >> set_debugreg(vcpu->arch.eff_db[2], 2); >> set_debugreg(vcpu->arch.eff_db[3], 3); >> set_debugreg(vcpu->arch.dr6, 6); >> - vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD; >> + vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_NEED_RELOAD; >> } >> >> kvm_x86_ops.run(vcpu); >> @@ -8424,7 +8424,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) >> kvm_update_dr0123(vcpu); >> kvm_update_dr6(vcpu); >> kvm_update_dr7(vcpu); >> - vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD; >> + vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_NEED_RELOAD; > > This is the path that I think would really benefit from DIRTY, it took me > several reads to catch that kvm_update_dr0123() will set RELOAD. > >> } >> >> /* >> -- >> 2.20.1 >>