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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150/* 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 <linux/errno.h>#include <linux/string.h>#include <linux/types.h>
#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 intsvsm_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 intsvsm_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_ */