From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) (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 2C0A837CD32; Thu, 4 Jun 2026 07:20:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780557624; cv=none; b=UiYW4aCv3bcdfzN2r6NTTjamtoOsuwlGJNYR9ya0uEdLLdb8DNFQk6bNjT2Ou4hFqMEagexHd9zxoBHkcvCXTVLuJdIM35xeO7+j8PGuzRVp8oYRxKRiOaLHZ28zTja5hKlX4P6amhgCa3HJ4sczUzp3C9Wb2RssBpYadqg0O0o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780557624; c=relaxed/simple; bh=+uJNHgFWw32KJn+Dd7evwkhd1RVCZfNmZgMtwDgY/EY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CbRp1OSgrZdduYOIx3vC6psL56hUfMBXKfnazeKdBE5yQ8RDYUq+S03OIS/kkND83AGVzXcxssjYqpG+1EZbHXxnC1WOu2WZbQivXY2yk12UFO1KtQ2jhv5vrgUEnUyhOV5nlXni2wdQUd3xN8Ipd7+gRWOrQ3JNHV7NFRSzLSE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=ZjMSbKs2; arc=none smtp.client-ip=192.198.163.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ZjMSbKs2" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1780557623; x=1812093623; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=+uJNHgFWw32KJn+Dd7evwkhd1RVCZfNmZgMtwDgY/EY=; b=ZjMSbKs2bnqJl/i6FEsdhPgw5Ep3m1J+AdMZfNvq/fcXU0ZzOTFad/Wr E57lchreOdjVQ2ABrmPL+Rq4iHr2ROnOFNxgPCf7Ttvjxb40ziXCd2voh nKyNIKs6Mqn/qkv4ilvO7mqmbrnKv6P4iVWGWVL3DIpg4UwJo8Um5P4QU y48kwjwCrHGsR611XhFxfzGjfGuFoBS+CAWH3tzVc+LcYKDlVUseWusmF N4DkSiCCYvdwNrSnlmNvG2uI/cEjUuewRAsuHPcply34j3VNHeJm1e70o o+yYiRFq+PM/ik4qpvCVuLORcqZ3WiV96SWGSpRuBH2SKbLU0pv4ckHyy Q==; X-CSE-ConnectionGUID: 5ff5T1H+TWmKDXpCAeIboQ== X-CSE-MsgGUID: GI1YWSz4SlO5zNTIm0AKyQ== X-IronPort-AV: E=McAfee;i="6800,10657,11806"; a="92751770" X-IronPort-AV: E=Sophos;i="6.24,186,1774335600"; d="scan'208";a="92751770" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jun 2026 00:20:22 -0700 X-CSE-ConnectionGUID: D008F64YSh+QNDdzXWub0A== X-CSE-MsgGUID: 5xcgOHJ6TbS38DYDCFwIhQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,186,1774335600"; d="scan'208";a="248410251" Received: from unknown (HELO [10.238.2.24]) ([10.238.2.24]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jun 2026 00:20:21 -0700 Message-ID: <014f4cee-8865-4767-a460-d991a7a67448@linux.intel.com> Date: Thu, 4 Jun 2026 15:20:18 +0800 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 4/4] KVM: x86: TDX: Report CORE_CAPABILITIES as supported To: Xiaoyao Li Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, seanjc@google.com, pbonzini@redhat.com, rick.p.edgecombe@intel.com, chao.gao@intel.com, kai.huang@intel.com References: <20260604023314.3907511-1-binbin.wu@linux.intel.com> <20260604023314.3907511-5-binbin.wu@linux.intel.com> <883588d1-27a2-4874-b832-5b1b62db3cb9@intel.com> Content-Language: en-US From: Binbin Wu In-Reply-To: <883588d1-27a2-4874-b832-5b1b62db3cb9@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 6/4/2026 2:53 PM, Xiaoyao Li wrote: > On 6/4/2026 10:33 AM, Binbin Wu wrote: >> Add CORE_CAPABILITIES (CPUID.0x7.0.EDX[30]) to the TDX configurable >> CPUID allowlist to accommodate legacy TDX module behavior. >> >> KVM doesn't support MSR_IA32_CORE_CAPS, however, some older TDX specs >> define CORE_CAPABILITIES CPUID bit as fixed-1.  As a result, userspace >> may expect this bit to be enabled in the TDX module for TDs.  When the >> CPUID bit becomes a directly configurable without reporting to the >> userspace, it can not be enabled.  To avoid confusing userspace, report >> CORE_CAPABILITIES to userspace via KVM_TDX_CAPABILITIES. >> >> Although KVM could determine the real CPUID setting by reading the >> metadata via SEAMCALL after KVM_TDX_INIT_VM, doing so is overkill to >> cover such a corner case.  If CORE_CAPABILITIES is exposed to a TDX >> guest, and the guest reads it, simply return 0. > > shouldn't this patch be put as patch 02 instead of 04? > > Patch 02 and 03 in this series break the old QEMU and then patch 04 fixes the broken. This is not friendly to the bisect. Good point. I will reorder the patch in the later version if the direction of this patch series is acked by maintainers.