sm501: Add missing arbitration control register
[qemu.git] / hw / tpm / tpm_util.c
1 /*
2 * TPM utility functions
3 *
4 * Copyright (c) 2010 - 2015 IBM Corporation
5 * Authors:
6 * Stefan Berger <stefanb@us.ibm.com>
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, see <http://www.gnu.org/licenses/>
20 */
21
22 #include "qemu/osdep.h"
23 #include "tpm_util.h"
24 #include "tpm_int.h"
25
26 /*
27 * A basic test of a TPM device. We expect a well formatted response header
28 * (error response is fine) within one second.
29 */
30 static int tpm_util_test(int fd,
31 unsigned char *request,
32 size_t requestlen,
33 uint16_t *return_tag)
34 {
35 struct tpm_resp_hdr *resp;
36 fd_set readfds;
37 int n;
38 struct timeval tv = {
39 .tv_sec = 1,
40 .tv_usec = 0,
41 };
42 unsigned char buf[1024];
43
44 n = write(fd, request, requestlen);
45 if (n < 0) {
46 return errno;
47 }
48 if (n != requestlen) {
49 return EFAULT;
50 }
51
52 FD_ZERO(&readfds);
53 FD_SET(fd, &readfds);
54
55 /* wait for a second */
56 n = select(fd + 1, &readfds, NULL, NULL, &tv);
57 if (n != 1) {
58 return errno;
59 }
60
61 n = read(fd, &buf, sizeof(buf));
62 if (n < sizeof(struct tpm_resp_hdr)) {
63 return EFAULT;
64 }
65
66 resp = (struct tpm_resp_hdr *)buf;
67 /* check the header */
68 if (be32_to_cpu(resp->len) != n) {
69 return EBADMSG;
70 }
71
72 *return_tag = be16_to_cpu(resp->tag);
73
74 return 0;
75 }
76
77 /*
78 * Probe for the TPM device in the back
79 * Returns 0 on success with the version of the probed TPM set, 1 on failure.
80 */
81 int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version)
82 {
83 /*
84 * Sending a TPM1.2 command to a TPM2 should return a TPM1.2
85 * header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e)
86 *
87 * Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the
88 * header.
89 * Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag
90 * in the header and an error code.
91 */
92 const struct tpm_req_hdr test_req = {
93 .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
94 .len = cpu_to_be32(sizeof(test_req)),
95 .ordinal = cpu_to_be32(TPM_ORD_GetTicks),
96 };
97
98 const struct tpm_req_hdr test_req_tpm2 = {
99 .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
100 .len = cpu_to_be32(sizeof(test_req_tpm2)),
101 .ordinal = cpu_to_be32(TPM2_CC_ReadClock),
102 };
103 uint16_t return_tag;
104 int ret;
105
106 /* Send TPM 2 command */
107 ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req_tpm2,
108 sizeof(test_req_tpm2), &return_tag);
109 /* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */
110 if (!ret && return_tag == TPM2_ST_NO_SESSIONS) {
111 *tpm_version = TPM_VERSION_2_0;
112 return 0;
113 }
114
115 /* Send TPM 1.2 command */
116 ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req,
117 sizeof(test_req), &return_tag);
118 if (!ret && return_tag == TPM_TAG_RSP_COMMAND) {
119 *tpm_version = TPM_VERSION_1_2;
120 /* this is a TPM 1.2 */
121 return 0;
122 }
123
124 *tpm_version = TPM_VERSION_UNSPEC;
125
126 return 1;
127 }