From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D551E38F220; Fri, 23 Jan 2026 06:02:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769148179; cv=none; b=Xd8SeaIhOASzt0aWNcizehrVvGUulI8iZeEBpDtP3JlCyfuxKI4DjKFm+JAxwv9sfttTQTOzIVuoJ78mp+RE2yRbCWukueq9fGDVK6rzYAd/X1+QgRZMUBQyLNKtZyUIfGvpalb1TDzO9EUGTcgxUxmbx8carV4hSvvYprpTn0I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769148179; c=relaxed/simple; bh=w5QxVYjLpIz8ZxUQ65k5wpaYI4icRM4cGhjOapYy8Z0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=giZz/x7yhkKpbRWmCcp0uR1CCPqKUCRioN9WqKEAkb2Mfyy0EoDY855sRe08mp/vZjIzTphhJzNM+r3K5yCm2ScwoZ1CuOcoxxr+WDPeWhbJVEGAE1u9YqJ34qC9h65ztBfYkBzD5qyHeLY+o/l1+dX7yL22A77h0jEWq0RHIWM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=ZTPEoQfJ; arc=none smtp.client-ip=192.198.163.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ZTPEoQfJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1769148175; x=1800684175; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=w5QxVYjLpIz8ZxUQ65k5wpaYI4icRM4cGhjOapYy8Z0=; b=ZTPEoQfJtE0orbEcIAkgM8pf8YzcN5YdKFbWoVYTUDKIUoiKcfeZx6Hd fb0t+3UROa6oFEnQlGbORT0NgAaVqkhscU97vvTz3Z2quC9egrLPVz7Lh g1giNoBLD2Xv/2Q2cAeO1MXAEs6gxZsVl4p2IKorilrdyvFXoNPhBzxJ1 9Ghw9r6ye2MrlZ0qrhWgDv8oSlWIwALMaJJv2Hos+U+hL8qBs5m3j0rEx belowqfcQvCqTmj0zNuW7js8+h440kgP391coAWr/ve2Jiup/sYnNXxwd 0gqpOEd3yrSEH5Dl0vQvfkKTmH1BD0m8vTdrKh6q/8qTtxChwxlgwEzIS A==; X-CSE-ConnectionGUID: k3lz4uVYSKuP/2DPJoq20A== X-CSE-MsgGUID: kF4t4UUpTKCSQ8/vRAmp3A== X-IronPort-AV: E=McAfee;i="6800,10657,11679"; a="69417417" X-IronPort-AV: E=Sophos;i="6.21,247,1763452800"; d="scan'208";a="69417417" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jan 2026 22:02:50 -0800 X-CSE-ConnectionGUID: f/khXmrmScWfxE2vMTZf/g== X-CSE-MsgGUID: yLN9rmbjQ/muHeqDGzWHjw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,247,1763452800"; d="scan'208";a="211398318" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.240.173]) ([10.124.240.173]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jan 2026 22:02:46 -0800 Message-ID: Date: Fri, 23 Jan 2026 14:02:42 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/4] KVM: x86: Advertise AMX CPUIDs in subleaf 0x1E.0x1 to userspace To: Zhao Liu , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Paolo Bonzini , Sean Christopherson , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Chao Gao , Xudong Hao References: <20251120050720.931449-1-zhao1.liu@intel.com> <20251120050720.931449-3-zhao1.liu@intel.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20251120050720.931449-3-zhao1.liu@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 11/20/2025 1:07 PM, Zhao Liu wrote: > In addition to the new features, CPUID 0x1E.0x1.EAX[bits 0-3] are > mirrored positions of existing AMX feature bits distributed across the > 0x7 leaves. To avoid duplicate feature names, name these mirror bits > with a *_MIRROR suffix, and define them in reverse_cpuid.h as KVM-only > features as well. It looks that KVM can emulate the mirroring CPUIDs regardless of whether hardware supports subleaf 1. However, given such emulation provides no real benefit but complicates KVM implementation, this patch looks good to me.