From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 718ED253B67; Wed, 26 Mar 2025 19:27:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743017233; cv=none; b=l+RTEifZEJndSgTACGn0GoTJpyuJEmeooRq2kbMt4svZRbcTVLRgbVVvyfk96194iHZTpkHvXkbozchlMr1ufj6U13Sgd03yz0G6SKyhA842O/yjX19y818Zv7SwhpgzA+ulGm/iABLCL01Xt98wJZbQ35/5NO+t3JAxF3L+4fo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743017233; c=relaxed/simple; bh=5iHQPfbctrSC7dSBsYc3jaiqsRDAIya5ZCYxpgK5Nc4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mnR7OaVbRq4yJ9OSsnfQzmTTPX4VI8Pr1Al1Xmu6guwtH2ygHRt0eUK950YkPlhVHfLk/QI3zM8u7Rj/eWn7zpXV829jHOJ2U0qS7051xmvUUZcYYT6Ajp/5DnKCHek8CpLFqF2yxbFxJeL64Jq0E7toPGJgUbgY2MqJjLSWIvM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O7H1zHfe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="O7H1zHfe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62DE0C4CEE2; Wed, 26 Mar 2025 19:27:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743017232; bh=5iHQPfbctrSC7dSBsYc3jaiqsRDAIya5ZCYxpgK5Nc4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=O7H1zHfeFlt52dwrzEEh5mv4LpX2PNy/dOB7Wd8PNZ7PD5XIkS3iBjuyc2MkouA1n FjVoON4CpOEBhrutKCQUlPg77r4OQ/5HDF3ZX1hug+vUzGHYmbYXN0Iit67t7lMV1l JtXWIA4m/cuUp5IdkWk7onZt9TtIcVOKVNbEg43VmW8CIYQnjpWwtPiH+yBhz4aYkh tC3lFgJYcDDzRV5uw0Ss5b2KkJEzoQlnKJ7fgnx4qqb9WTzHlu+6guLfT0UVAECEZY 5/c1KkVMAGQJoGvyr7ovucnmCvciKuS97wmmyJtpemYl0wrWSZJyAZGotWeXXrjo/L egHC64ZXFLB2Q== Date: Wed, 26 Mar 2025 21:27:08 +0200 From: Jarkko Sakkinen To: Stefano Garzarella Cc: Joerg Roedel , Ingo Molnar , Dave Hansen , Peter Huewe , Tom Lendacky , Thomas Gleixner , x86@kernel.org, James Bottomley , linux-kernel@vger.kernel.org, Borislav Petkov , Jason Gunthorpe , "H. Peter Anvin" , linux-coco@lists.linux.dev, Claudio Carvalho , Dov Murik , Dionna Glaze , linux-integrity@vger.kernel.org Subject: Re: [PATCH v4 2/4] svsm: add header with SVSM_VTPM_CMD helpers Message-ID: References: <20250324104653.138663-1-sgarzare@redhat.com> <20250324104653.138663-3-sgarzare@redhat.com> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250324104653.138663-3-sgarzare@redhat.com> On Mon, Mar 24, 2025 at 11:46:47AM +0100, Stefano Garzarella wrote: > From: Stefano Garzarella > > Helpers for the SVSM_VTPM_CMD calls used by the vTPM protocol defined by > the AMD SVSM spec [1]. > > The vTPM protocol follows the Official TPM 2.0 Reference Implementation > (originally by Microsoft, now part of the TCG) simulator protocol. > > [1] "Secure VM Service Module for SEV-SNP Guests" > Publication # 58019 Revision: 1.00 > > Co-developed-by: James Bottomley > Signed-off-by: James Bottomley > Co-developed-by: Claudio Carvalho > Signed-off-by: Claudio Carvalho > Signed-off-by: Stefano Garzarella > --- > v4: > - used svsm_vtpm_ prefix consistently [Jarkko] > - removed __packed where not needed [Jarkko] > - expanded headers to avoid obfuscation [Jarkko] > - used `buf` instead of `inbuf`/`outbuf` [Jarkko] > - added more documentation quoting the specification > - removed TPM_* macros since we only use TPM_SEND_COMMAND in one place > and don't want dependencies on external headers, but put the value > directly as specified in the AMD SVSM specification > - header renamed in tpm_svsm.h so it will fall under TPM DEVICE DRIVER > section [Borislav, Jarkko] > v3: > - renamed header and prefix to make clear it's related to the SVSM vTPM > protocol > - renamed fill/parse functions [Tom] > - removed link to the spec because those URLs are unstable [Borislav] > --- > include/linux/tpm_svsm.h | 149 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 149 insertions(+) > create mode 100644 include/linux/tpm_svsm.h > > diff --git a/include/linux/tpm_svsm.h b/include/linux/tpm_svsm.h > new file mode 100644 > index 000000000000..38e341f9761a > --- /dev/null > +++ b/include/linux/tpm_svsm.h > @@ -0,0 +1,149 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (C) 2023 James.Bottomley@HansenPartnership.com > + * Copyright (C) 2025 Red Hat, Inc. All Rights Reserved. > + * > + * Helpers for the SVSM_VTPM_CMD calls used by the vTPM protocol defined by the > + * AMD SVSM spec [1]. > + * > + * The vTPM protocol follows the Official TPM 2.0 Reference Implementation > + * (originally by Microsoft, now part of the TCG) simulator protocol. > + * > + * [1] "Secure VM Service Module for SEV-SNP Guests" > + * Publication # 58019 Revision: 1.00 > + */ > +#ifndef _TPM_SVSM_H_ > +#define _TPM_SVSM_H_ > + > +#include > +#include > +#include > + > +#define SVSM_VTPM_MAX_BUFFER 4096 /* max req/resp buffer size */ > + > +/** > + * struct svsm_vtpm_request - Generic request for single word command > + * @cmd: The command to send > + * > + * Defined by AMD SVSM spec [1] in section "8.2 SVSM_VTPM_CMD Call" - > + * Table 15: vTPM Common Request/Response Structure > + * Byte Size     In/Out    Description > + * Offset    (Bytes) > + * 0x000     4          In        Platform command > + *                         Out       Platform command response size > + */ > +struct svsm_vtpm_request { > + u32 cmd; > +}; > + > +/** > + * struct svsm_vtpm_response - Generic response > + * @size: The response size (zero if nothing follows) > + * > + * Defined by AMD SVSM spec [1] in section "8.2 SVSM_VTPM_CMD Call" - > + * Table 15: vTPM Common Request/Response Structure > + * Byte Size     In/Out    Description > + * Offset    (Bytes) > + * 0x000     4          In        Platform command > + *                         Out       Platform command response size > + * > + * Note: most TCG Simulator commands simply return zero here with no indication > + * of success or failure. > + */ > +struct svsm_vtpm_response { > + u32 size; > +}; > + > +/** > + * struct svsm_vtpm_cmd_request - Structure for a TPM_SEND_COMMAND request > + * @cmd: The command to send (must be TPM_SEND_COMMAND) > + * @locality: The locality > + * @buf_size: The size of the input buffer following > + * @buf: A buffer of size buf_size > + * > + * Defined by AMD SVSM spec [1] in section "8.2 SVSM_VTPM_CMD Call" - > + * Table 16: TPM_SEND_COMMAND Request Structure > + * Byte Size Meaning > + * Offset    (Bytes) > + * 0x000     4          Platform command (8) > + * 0x004     1          Locality (must-be-0) > + * 0x005     4          TPM Command size (in bytes) > + * 0x009     Variable   TPM Command > + * > + * Note: the TCG Simulator expects @buf_size to be equal to the size of the > + * specific TPM command, otherwise an TPM_RC_COMMAND_SIZE error is returned. > + */ > +struct svsm_vtpm_cmd_request { > + u32 cmd; > + u8 locality; > + u32 buf_size; > + u8 buf[]; > +} __packed; > + > +/** > + * struct svsm_vtpm_cmd_response - Structure for a TPM_SEND_COMMAND response > + * @buf_size: The size of the output buffer following > + * @buf: A buffer of size buf_size > + * > + * Defined by AMD SVSM spec [1] in section "8.2 SVSM_VTPM_CMD Call" - > + * Table 17: TPM_SEND_COMMAND Response Structure > + * Byte Size Meaning > + * Offset    (Bytes) > + * 0x000     4          Response size (in bytes) > + * 0x004     Variable   Response > + */ > +struct svsm_vtpm_cmd_response { > + u32 buf_size; > + u8 buf[]; > +}; > + > +/** > + * svsm_vtpm_cmd_request_fill() - Fill a TPM_SEND_COMMAND request to be sent to SVSM > + * @req: The struct svsm_vtpm_cmd_request to fill > + * @locality: The locality > + * @buf: The buffer from where to copy the payload of the command > + * @len: The size of the buffer > + * > + * Return: 0 on success, negative error code on failure. > + */ > +static inline int > +svsm_vtpm_cmd_request_fill(struct svsm_vtpm_cmd_request *req, u8 locality, > + const u8 *buf, size_t len) > +{ > + if (len > SVSM_VTPM_MAX_BUFFER - sizeof(*req)) > + return -EINVAL; > + > + req->cmd = 8; /* TPM_SEND_COMMAND */ > + req->locality = locality; > + req->buf_size = len; > + > + memcpy(req->buf, buf, len); > + > + return 0; > +} > + > +/** > + * svsm_vtpm_cmd_response_parse() - Parse a TPM_SEND_COMMAND response received from SVSM > + * @resp: The struct svsm_vtpm_cmd_response to parse > + * @buf: The buffer where to copy the response > + * @len: The size of the buffer > + * > + * Return: buffer size filled with the response on success, negative error > + * code on failure. > + */ > +static inline int > +svsm_vtpm_cmd_response_parse(const struct svsm_vtpm_cmd_response *resp, u8 *buf, > + size_t len) > +{ > + if (len < resp->buf_size) > + return -E2BIG; > + > + if (resp->buf_size > SVSM_VTPM_MAX_BUFFER - sizeof(*resp)) > + return -EINVAL; // Invalid response from the platform TPM > + > + memcpy(buf, resp->buf, resp->buf_size); > + > + return resp->buf_size; > +} > + > +#endif /* _TPM_SVSM_H_ */ > -- > 2.49.0 > Reviewed-by: Jarkko Sakkinen BR, Jarkko