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 00465C433EF for ; Tue, 1 Feb 2022 23:14:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242783AbiBAXOx (ORCPT ); Tue, 1 Feb 2022 18:14:53 -0500 Received: from mga05.intel.com ([192.55.52.43]:29313 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229626AbiBAXOv (ORCPT ); Tue, 1 Feb 2022 18:14:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643757291; x=1675293291; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=JPI3uuMW8X1fbYmB/lxgAinKYS1OEHseGPfdAUaTibs=; b=iTPZRxXalG8hJyId/LBj+zzM0N+RMLTaVdLsQsEH50ianymNn9OS18ak tP1z0vFom74gKKXS6fklxvpYxvUcLacmpelDO9UWQ6aYBt2/74+hd24Gb TuyLyJ5UAL+9l7DiptD4ZSDnYbRaHasbW8cAMn85gcDskpoSoyOHWzfcb PgU3gaMkTWUUPWkukW14liED9uK2vddUr588Ai4XMdWbzMw/9gmTagc7M lX5fvJiYuIZvOx2jzt4UA7l2l4Ga+fD6meLgv/Llz1HmA1Ye8kekXTJOj /HGgDrrm2BtqqQhYyLwaVKix6mngWgPBn5sa3xY/gXb7+IAyZMkQU8YbF g==; X-IronPort-AV: E=McAfee;i="6200,9189,10245"; a="334174221" X-IronPort-AV: E=Sophos;i="5.88,335,1635231600"; d="scan'208";a="334174221" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2022 15:14:51 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,335,1635231600"; d="scan'208";a="698591818" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga005.jf.intel.com with ESMTP; 01 Feb 2022 15:14:45 -0800 Received: by black.fi.intel.com (Postfix, from userid 1000) id 5AF673B7; Wed, 2 Feb 2022 01:14:59 +0200 (EET) Date: Wed, 2 Feb 2022 02:14:59 +0300 From: "Kirill A. Shutemov" To: Thomas Gleixner Cc: mingo@redhat.com, bp@alien8.de, dave.hansen@intel.com, luto@kernel.org, peterz@infradead.org, sathyanarayanan.kuppuswamy@linux.intel.com, aarcange@redhat.com, ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com, hpa@zytor.com, jgross@suse.com, jmattson@google.com, joro@8bytes.org, jpoimboe@redhat.com, knsathya@kernel.org, pbonzini@redhat.com, sdeep@vmware.com, seanjc@google.com, tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCHv2 01/29] x86/tdx: Detect running as a TDX guest in early boot Message-ID: <20220201231459.2doc4iaibmuua4qk@black.fi.intel.com> References: <20220124150215.36893-1-kirill.shutemov@linux.intel.com> <20220124150215.36893-2-kirill.shutemov@linux.intel.com> <87fsp2z8p8.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87fsp2z8p8.ffs@tglx> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 01, 2022 at 08:29:55PM +0100, Thomas Gleixner wrote: > Kirill, > > On Mon, Jan 24 2022 at 18:01, Kirill A. Shutemov wrote: > > Just a nitpick... > > > +static bool tdx_guest_detected __ro_after_init; > > + > > +bool is_tdx_guest(void) > > +{ > > + return tdx_guest_detected; > > +} > > + > > +void __init tdx_early_init(void) > > +{ > > + u32 eax, sig[3]; > > + > > + cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2], &sig[1]); > > + > > + if (memcmp(TDX_IDENT, sig, 12)) > > + return; > > + > > + tdx_guest_detected = true; > > + > > + setup_force_cpu_cap(X86_FEATURE_TDX_GUEST); > > So with that we have two ways to detect a TDX guest: > > - tdx_guest_detected > > - X86_FEATURE_TDX_GUEST > > Shouldn't X86_FEATURE_TDX_GUEST be good enough? Right. We have only 3 callers of is_tdx_guest() in cc_platform.c I will replace them with cpu_feature_enabled(X86_FEATURE_TDX_GUEST). Thanks. -- Kirill A. Shutemov