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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, HK_RANDOM_FROM,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 B2029C17461 for ; Tue, 5 Nov 2019 12:51:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FE3721D7F for ; Tue, 5 Nov 2019 12:51:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388222AbfKEMv5 (ORCPT ); Tue, 5 Nov 2019 07:51:57 -0500 Received: from mga04.intel.com ([192.55.52.120]:64062 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388008AbfKEMv4 (ORCPT ); Tue, 5 Nov 2019 07:51:56 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Nov 2019 04:51:56 -0800 X-IronPort-AV: E=Sophos;i="5.68,271,1569308400"; d="scan'208";a="195809553" Received: from xiaoyaol-mobl.ccr.corp.intel.com (HELO [10.239.13.123]) ([10.239.13.123]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/AES256-SHA; 05 Nov 2019 04:51:53 -0800 Subject: Re: [PATCH] KVM: X86: Dynamically allocating MSR number lists(msrs_to_save[], emulated_msrs[], msr_based_features[]) To: Paolo Bonzini , Chenyi Qiang , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Sean Christopherson , Vitaly Kuznetsov , Jim Mattson , Joerg Roedel Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20191105092031.8064-1-chenyi.qiang@intel.com> <4a5fd5b4-64b7-726a-57a5-a5c669ce84f6@redhat.com> From: Xiaoyao Li Message-ID: <477da390-4bdb-c25d-24b1-5b57c3bf78bb@intel.com> Date: Tue, 5 Nov 2019 20:51:51 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <4a5fd5b4-64b7-726a-57a5-a5c669ce84f6@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On 11/5/2019 7:30 PM, Paolo Bonzini wrote: > On 05/11/19 10:20, Chenyi Qiang wrote: >> The three msr number lists(msrs_to_save[], emulated_msrs[] and >> msr_based_features[]) are global arrays of kvm.ko, which are >> initialized/adjusted (copy supported MSRs forward to override the >> unsupported MSRs) when installing kvm-{intel,amd}.ko, but it doesn't >> reset these three arrays to their initial value when uninstalling >> kvm-{intel,amd}.ko. Thus, at the next installation, kvm-{intel,amd}.ko >> will initialize the modified arrays with some MSRs lost and some MSRs >> duplicated. >> >> So allocate and initialize these three MSR number lists dynamically when >> installing kvm-{intel,amd}.ko and free them when uninstalling. >> >> Cc: stable@vger.kernel.org >> Reviewed-by: Xiaoyao Li >> Signed-off-by: Chenyi Qiang >> --- >> arch/x86/kvm/x86.c | 86 ++++++++++++++++++++++++++++++---------------- >> 1 file changed, 57 insertions(+), 29 deletions(-) >> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index ff395f812719..08efcf6351cc 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -1132,13 +1132,15 @@ EXPORT_SYMBOL_GPL(kvm_rdpmc); >> * List of msr numbers which we expose to userspace through KVM_GET_MSRS >> * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST. >> * >> - * This list is modified at module load time to reflect the >> + * The three msr number lists(msrs_to_save, emulated_msrs, msr_based_features) >> + * are allocated and initialized at module load time and freed at unload time. >> + * msrs_to_save is selected from the msrs_to_save_all to reflect the >> * capabilities of the host cpu. This capabilities test skips MSRs that are >> - * kvm-specific. Those are put in emulated_msrs; filtering of emulated_msrs >> + * kvm-specific. Those are put in emulated_msrs_all; filtering of emulated_msrs >> * may depend on host virtualization features rather than host cpu features. >> */ >> >> -static u32 msrs_to_save[] = { >> +const u32 msrs_to_save_all[] = { > > This can remain static. How about static const u32 msrs_to_save_all[] ? Or you think static is enough? >> MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP, >> MSR_STAR, >> #ifdef CONFIG_X86_64 >> @@ -1179,9 +1181,10 @@ static u32 msrs_to_save[] = { >> MSR_ARCH_PERFMON_EVENTSEL0 + 16, MSR_ARCH_PERFMON_EVENTSEL0 + 17, >> }; >> >> +static u32 *msrs_to_save; > > You can use ARRAY_SIZE to allocate the destination arrays statically. It's much better, then we don't need to allocation and free. > Paolo >