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=-5.2 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 1BFE6C33CAB for ; Mon, 13 Jan 2020 05:40:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC6FF2082E for ; Mon, 13 Jan 2020 05:40:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727014AbgAMFkU (ORCPT ); Mon, 13 Jan 2020 00:40:20 -0500 Received: from mga02.intel.com ([134.134.136.20]:2721 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726017AbgAMFkT (ORCPT ); Mon, 13 Jan 2020 00:40:19 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Jan 2020 21:40:18 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,427,1571727600"; d="scan'208";a="243089700" Received: from local-michael-cet-test.sh.intel.com (HELO localhost) ([10.239.159.128]) by fmsmga001.fm.intel.com with ESMTP; 12 Jan 2020 21:40:17 -0800 Date: Mon, 13 Jan 2020 13:44:38 +0800 From: Yang Weijiang To: Sean Christopherson Cc: Yang Weijiang , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, jmattson@google.com, yu.c.zhang@linux.intel.com, alazar@bitdefender.com, edwin.zhai@intel.com Subject: Re: [RESEND PATCH v10 02/10] vmx: spp: Add control flags for Sub-Page Protection(SPP) Message-ID: <20200113054438.GA12253@local-michael-cet-test.sh.intel.com> References: <20200102061319.10077-1-weijiang.yang@intel.com> <20200102061319.10077-3-weijiang.yang@intel.com> <20200110165859.GB21485@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200110165859.GB21485@linux.intel.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 10, 2020 at 08:58:59AM -0800, Sean Christopherson wrote: > On Thu, Jan 02, 2020 at 02:13:11PM +0800, Yang Weijiang wrote: > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > > index e3394c839dea..5713e8a6224c 100644 > > --- a/arch/x86/kvm/vmx/vmx.c > > +++ b/arch/x86/kvm/vmx/vmx.c > > @@ -60,6 +60,7 @@ > > #include "vmcs12.h" > > #include "vmx.h" > > #include "x86.h" > > +#include "../mmu/spp.h" > > The ".." should be unnecessary, e.g. x86.h is obviously a level up. > Sean, thanks a lot for the feedback! Will change this. > > MODULE_AUTHOR("Qumranet"); > > MODULE_LICENSE("GPL"); > > @@ -111,6 +112,7 @@ module_param_named(pml, enable_pml, bool, S_IRUGO); > > > > static bool __read_mostly dump_invalid_vmcs = 0; > > module_param(dump_invalid_vmcs, bool, 0644); > > +static bool __read_mostly spp_supported = 0; > > s/spp_supported/enable_spp to be consistent with all the other booleans. > > Is there a reason this isn't exposed as a module param? > Yes, in original versions, SPP is enbled by a module param, so called "static enable", considering the SPP bitmap pre-allocated is a bit large, the from v3, it's changed to "dynamic enable", i.e., user application need to enable SPP via init_spp IOCTL(later changed to via ENABLE_CAP) to remove the pre-allocation, so the flag now is used to cross-check SPP status between functions. Will change the name. > And if this is to be on by default, then the flag itself should be > initialized to '1' so that it's clear to readers that the feature is > enabled by default (if it's supported). Looking at only this code, I would > think that SPP is forced off and can't be enabled. > > That being said, turning on the enable_spp control flag should be the last > patch in the series, i.e. it shouldn't be turned on until all the > underlying support code is in place. So, I would keep this as is, but > invert the code in hardware_setup() below. That way the flag exists and > is checked, but can't be turned on without modifying the code. Then when > all is said and done, you can add a patch to introduce the module param > and turn on the flag by default (if that's indeed what we want). > You're right, I'll re-order the patch to enable SPP bit in the last patch, thanks! > > #define MSR_BITMAP_MODE_X2APIC 1 > > #define MSR_BITMAP_MODE_X2APIC_APICV 2 > > @@ -2391,6 +2393,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf, > > SECONDARY_EXEC_RDSEED_EXITING | > > SECONDARY_EXEC_RDRAND_EXITING | > > SECONDARY_EXEC_ENABLE_PML | > > + SECONDARY_EXEC_ENABLE_SPP | > > SECONDARY_EXEC_TSC_SCALING | > > SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE | > > SECONDARY_EXEC_PT_USE_GPA | > > @@ -4039,6 +4042,9 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx) > > if (!enable_pml) > > exec_control &= ~SECONDARY_EXEC_ENABLE_PML; > > > > + if (!spp_supported) > > + exec_control &= ~SECONDARY_EXEC_ENABLE_SPP; > > + > > if (vmx_xsaves_supported()) { > > /* Exposing XSAVES only when XSAVE is exposed */ > > bool xsaves_enabled = > > @@ -7630,6 +7636,9 @@ static __init int hardware_setup(void) > > if (!cpu_has_vmx_flexpriority()) > > flexpriority_enabled = 0; > > > > + if (cpu_has_vmx_ept_spp() && enable_ept) > > + spp_supported = 1; > > As above, invert this to disable spp when it's not supported, or when EPT > is disabled (or not supported). > Sure,thank you! > > + > > if (!cpu_has_virtual_nmis()) > > enable_vnmi = 0; > > > > -- > > 2.17.2 > >