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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7940AC61DA3 for ; Tue, 21 Feb 2023 07:26:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233603AbjBUH03 (ORCPT ); Tue, 21 Feb 2023 02:26:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233607AbjBUH01 (ORCPT ); Tue, 21 Feb 2023 02:26:27 -0500 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C31C25B8D for ; Mon, 20 Feb 2023 23:26:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676964374; x=1708500374; h=message-id:subject:from:to:cc:date:in-reply-to: references:mime-version:content-transfer-encoding; bh=FBO5wXdrqkkhAJ4e+qH++0JjWPeGgBCsJJj8yqEccFs=; b=eeMrZHhKjtjABzBCMyiuP9GGxVPxi+XmOFHQDz+vJzU4C65VWlMm0yVZ M2XmElD+2FGqSQs4Gpat9661rToKslShzNZxqLbtTaHECCHi7GgODD1XM WdxfVG/WN/qC33M+tYCLX5LN7XTs2X37Kml2+Zmc0BNVmb6Mio83lSAxv YRG5itaUmRru7sNN7Tat3npiogr7jA7UwQD+NUL7F4BdgWl9TJdL78N+J k41jZK46N/FfQiXyI6WVOPqX4DTtQZcFvM1aB1EHYmLlFUFdESlZM6RQD Us++ND5plwwdZ6BzvgUW6xF0kRgUoqtSyH57c+pezTpUpn0Bjdr5Mxvz9 w==; X-IronPort-AV: E=McAfee;i="6500,9779,10627"; a="332572689" X-IronPort-AV: E=Sophos;i="5.97,315,1669104000"; d="scan'208";a="332572689" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Feb 2023 23:26:13 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10627"; a="701909813" X-IronPort-AV: E=Sophos;i="5.97,315,1669104000"; d="scan'208";a="701909813" Received: from sqa-gate.sh.intel.com (HELO robert-ivt.tsp.org) ([10.239.48.212]) by orsmga008.jf.intel.com with ESMTP; 20 Feb 2023 23:26:10 -0800 Message-ID: <587054f9715283ef4414af64dd69cda1f7597380.camel@linux.intel.com> Subject: Re: [PATCH v4 9/9] KVM: x86: LAM: Expose LAM CPUID to user space VMM From: Robert Hoo To: Binbin Wu , seanjc@google.com, pbonzini@redhat.com, yu.c.zhang@linux.intel.com, yuan.yao@linux.intel.com, jingqi.liu@intel.com, weijiang.yang@intel.com, chao.gao@intel.com, isaku.yamahata@intel.com Cc: kirill.shutemov@linux.intel.com, kvm@vger.kernel.org Date: Tue, 21 Feb 2023 15:26:09 +0800 In-Reply-To: <2c7c4d73-810e-6c9c-0480-46d68dedadc8@linux.intel.com> References: <20230209024022.3371768-1-robert.hu@linux.intel.com> <20230209024022.3371768-10-robert.hu@linux.intel.com> <2c7c4d73-810e-6c9c-0480-46d68dedadc8@linux.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-10.el7) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, 2023-02-21 at 13:47 +0800, Binbin Wu wrote: > On 2/9/2023 10:40 AM, Robert Hoo wrote: > > LAM feature is enumerated by (EAX=07H, ECX=01H):EAX.LAM[bit26]. > > > > Signed-off-by: Robert Hoo > > Reviewed-by: Jingqi Liu > > --- > > arch/x86/kvm/cpuid.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > > index b14653b61470..79f45cbe587e 100644 > > --- a/arch/x86/kvm/cpuid.c > > +++ b/arch/x86/kvm/cpuid.c > > @@ -664,7 +664,7 @@ void kvm_set_cpu_caps(void) > > > > kvm_cpu_cap_mask(CPUID_7_1_EAX, > > F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) | > > F(AMX_FP16) | > > - F(AVX_IFMA) > > + F(AVX_IFMA) | F(LAM) > > Do we allow to expose the LAM capability to guest when host kernel > disabled LAM feature (e.g. via clearcpuid)? No > > May be it should be handled similarly as LA57. > You mean expose LAM to guest based on HW capability rather than host status? Why is LA57 exposure like this? unlike most features. Without explicit rationality, I would tend to follow most conventions.