From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6E80A44C7C; Thu, 13 Feb 2025 22:17:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739485081; cv=none; b=I16WLd36gNMtKl/HzqZqYZbialCaq+UTu1609Qq0IFkmJC65gexlpGa0ZYZIuBhFbdkSMT1AbBfiZ1EyFRxiLJX3zpA1t8pOgU8aZPHGH/7kQ7MSGrbMzEy1Bf/4M8hLxwxPKITnGxkMNzSd+JQLUz5KxSYHQJAFcoby+OwowK0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739485081; c=relaxed/simple; bh=wqefMj2OjBMV9f903IECS9IfnZFQxMtV9+o7b+D27sU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=aFn6+IqNfM1WkVpdw8S5/FWNJQa5RcAJDi2Ogev9gSOecOU7PU6xxz+Jxk6jSByu8fdClVc9UGgIs3JJGKuVM0OdQCS/NjgrXKDbwc+xWliXifn9thGJ50FkyxRjMwkByfeXSoGjRVjkR6vO0DlS75saFAXdfrpEXD1+I8q7OJ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1B436106F; Thu, 13 Feb 2025 14:18:18 -0800 (PST) Received: from [10.122.17.146] (unknown [10.122.17.146]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 36CEA3F5A1; Thu, 13 Feb 2025 14:17:57 -0800 (PST) Message-ID: Date: Thu, 13 Feb 2025 16:17:56 -0600 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 v2 5/5] Documentation: tpm: add documentation for the CRB FF-A interface To: Jarkko Sakkinen Cc: linux-integrity@vger.kernel.org, peterhuewe@gmx.de, jgg@ziepe.ca, sudeep.holla@arm.com, rafael@kernel.org, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250212220548.400447-1-stuart.yoder@arm.com> <20250212220548.400447-6-stuart.yoder@arm.com> Content-Language: en-US From: Stuart Yoder In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2/13/25 4:11 PM, Jarkko Sakkinen wrote: > On Wed, Feb 12, 2025 at 04:05:48PM -0600, Stuart Yoder wrote: >> Add documentation providing details of how the CRB driver interacts >> with FF-A. >> >> Signed-off-by: Stuart Yoder >> --- >> Documentation/security/tpm/tpm_ffa_crb.rst | 65 ++++++++++++++++++++++ >> 1 file changed, 65 insertions(+) >> create mode 100644 Documentation/security/tpm/tpm_ffa_crb.rst >> >> diff --git a/Documentation/security/tpm/tpm_ffa_crb.rst b/Documentation/security/tpm/tpm_ffa_crb.rst >> new file mode 100644 >> index 000000000000..c70f8904a93d >> --- /dev/null >> +++ b/Documentation/security/tpm/tpm_ffa_crb.rst >> @@ -0,0 +1,65 @@ >> +.. SPDX-License-Identifier: GPL-2.0 >> + >> +======================== >> +TPM CRB over FF-A Driver >> +======================== >> + >> +The TPM Command Response Buffer (CRB) interface is a standard TPM interface >> +defined in the TCG PC Client Platform TPM Profile (PTP) Specification [1]_. >> +The CRB provides a structured set of control registers a client uses when >> +interacting with a TPM as well as a data buffer for storing TPM commands and >> +responses. A CRB interface can be implemented in: >> + >> +- hardware registers in a discrete TPM chip >> + >> +- in memory for a TPM running in isolated environment where shared memory >> + allows a client to interact with the TPM >> + >> +The Firmware Framework for Arm A-profile (FF-A) [2]_ is a specification >> +that defines interfaces and protocols for the following purposes: >> + >> +- Compartmentalize firmware into software partitions that run in the Arm >> + Secure world environment (also know as TrustZone) > > Does that also cover ARM CCA? Just a question (not a review question). No, CCA is for confidential VMs which is a separate trusted execution environment and FF-A is not used there. Thanks, Stuart