1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
|
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#if defined(__i386__) || defined(__x86_64__)
#include <cpuid.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include "confidential-virt-fundamental.h"
#include "confidential-virt.h"
#include "fd-util.h"
#include "fileio.h"
#include "missing_threads.h"
#include "string-table.h"
#include "utf8.h"
#if defined(__x86_64__)
static void cpuid(uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx) {
log_debug("CPUID func %" PRIx32 " %" PRIx32, *eax, *ecx);
__cpuid_count(*eax, *ecx, *eax, *ebx, *ecx, *edx);
log_debug("CPUID result %" PRIx32 " %" PRIx32 " %" PRIx32 " %" PRIx32, *eax, *ebx, *ecx, *edx);
}
static uint32_t cpuid_leaf(uint32_t eax, char ret_sig[static 13], bool swapped) {
/* zero-init as some queries explicitly require subleaf == 0 */
uint32_t sig[3] = {};
if (swapped)
cpuid(&eax, &sig[0], &sig[2], &sig[1]);
else
cpuid(&eax, &sig[0], &sig[1], &sig[2]);
memcpy(ret_sig, sig, sizeof(sig));
ret_sig[12] = 0; /* \0-terminate the string to make string comparison possible */
/* In some CI tests ret_sig doesn't contain valid UTF8 and prints garbage to the console */
log_debug("CPUID sig '%s'", strna(utf8_is_valid(ret_sig)));
return eax;
}
#define MSR_DEVICE "/dev/cpu/0/msr"
static uint64_t msr(uint64_t index) {
uint64_t ret;
ssize_t rv;
_cleanup_close_ int fd = -EBADF;
fd = open(MSR_DEVICE, O_RDONLY|O_CLOEXEC);
if (fd < 0) {
log_debug_errno(errno,
"Cannot open MSR device %s (index %" PRIu64 "), ignoring: %m",
MSR_DEVICE,
index);
return 0;
}
rv = pread(fd, &ret, sizeof(ret), index);
if (rv < 0) {
log_debug_errno(errno,
"Cannot read MSR device %s (index %" PRIu64 "), ignoring: %m",
MSR_DEVICE,
index);
return 0;
} else if (rv != sizeof(ret)) {
log_debug("Short read %zd bytes from MSR device %s (index %" PRIu64 "), ignoring",
rv,
MSR_DEVICE,
index);
return 0;
}
log_debug("MSR %" PRIu64 " result %" PRIu64 "", index, ret);
return ret;
}
static bool detect_hyperv_cvm(uint32_t isoltype) {
uint32_t eax, ebx, ecx, edx, feat;
char sig[13] = {};
feat = cpuid_leaf(CPUID_HYPERV_VENDOR_AND_MAX_FUNCTIONS, sig, false);
if (feat < CPUID_HYPERV_MIN || feat > CPUID_HYPERV_MAX)
return false;
if (memcmp(sig, CPUID_SIG_HYPERV, sizeof(sig)) != 0)
return false;
log_debug("CPUID is on hyperv");
eax = CPUID_HYPERV_FEATURES;
ebx = ecx = edx = 0;
cpuid(&eax, &ebx, &ecx, &edx);
if (ebx & CPUID_HYPERV_ISOLATION && !(ebx & CPUID_HYPERV_CPU_MANAGEMENT)) {
eax = CPUID_HYPERV_ISOLATION_CONFIG;
ebx = ecx = edx = 0;
cpuid(&eax, &ebx, &ecx, &edx);
if ((ebx & CPUID_HYPERV_ISOLATION_TYPE_MASK) == isoltype)
return true;
}
return false;
}
static ConfidentialVirtualization detect_sev(void) {
uint32_t eax, ebx, ecx, edx;
uint64_t msrval;
eax = CPUID_GET_HIGHEST_FUNCTION;
ebx = ecx = edx = 0;
cpuid(&eax, &ebx, &ecx, &edx);
if (eax < CPUID_AMD_GET_ENCRYPTED_MEMORY_CAPABILITIES)
return CONFIDENTIAL_VIRTUALIZATION_NONE;
eax = CPUID_AMD_GET_ENCRYPTED_MEMORY_CAPABILITIES;
ebx = ecx = edx = 0;
cpuid(&eax, &ebx, &ecx, &edx);
/* bit 1 == CPU supports SEV feature
*
* Note, Azure blocks this CPUID leaf from its SEV-SNP
* guests, so we must fallback to trying some HyperV
* specific CPUID checks.
*/
if (!(eax & EAX_SEV)) {
log_debug("No sev in CPUID, trying hyperv CPUID");
if (detect_hyperv_cvm(CPUID_HYPERV_ISOLATION_TYPE_SNP))
return CONFIDENTIAL_VIRTUALIZATION_SEV_SNP;
log_debug("No hyperv CPUID");
return CONFIDENTIAL_VIRTUALIZATION_NONE;
}
msrval = msr(MSR_AMD64_SEV);
/* Test reverse order, since the SEV-SNP bit implies
* the SEV-ES bit, which implies the SEV bit */
if (msrval & MSR_SEV_SNP)
return CONFIDENTIAL_VIRTUALIZATION_SEV_SNP;
if (msrval & MSR_SEV_ES)
return CONFIDENTIAL_VIRTUALIZATION_SEV_ES;
if (msrval & MSR_SEV)
return CONFIDENTIAL_VIRTUALIZATION_SEV;
return CONFIDENTIAL_VIRTUALIZATION_NONE;
}
static ConfidentialVirtualization detect_tdx(void) {
uint32_t eax, ebx, ecx, edx;
char sig[13] = {};
eax = CPUID_GET_HIGHEST_FUNCTION;
ebx = ecx = edx = 0;
cpuid(&eax, &ebx, &ecx, &edx);
if (eax < CPUID_INTEL_TDX_ENUMERATION)
return CONFIDENTIAL_VIRTUALIZATION_NONE;
cpuid_leaf(CPUID_INTEL_TDX_ENUMERATION, sig, true);
if (memcmp(sig, CPUID_SIG_INTEL_TDX, sizeof(sig)) == 0)
return CONFIDENTIAL_VIRTUALIZATION_TDX;
log_debug("No tdx in CPUID, trying hyperv CPUID");
if (detect_hyperv_cvm(CPUID_HYPERV_ISOLATION_TYPE_TDX))
return CONFIDENTIAL_VIRTUALIZATION_TDX;
return CONFIDENTIAL_VIRTUALIZATION_NONE;
}
static bool detect_hypervisor(void) {
uint32_t eax, ebx, ecx, edx;
bool is_hv;
eax = CPUID_PROCESSOR_INFO_AND_FEATURE_BITS;
ebx = ecx = edx = 0;
cpuid(&eax, &ebx, &ecx, &edx);
is_hv = ecx & CPUID_FEATURE_HYPERVISOR;
log_debug("CPUID is hypervisor: %s", yes_no(is_hv));
return is_hv;
}
static ConfidentialVirtualization detect_confidential_virtualization_impl(void) {
char sig[13] = {};
/* Skip everything on bare metal */
if (detect_hypervisor()) {
cpuid_leaf(0, sig, true);
if (memcmp(sig, CPUID_SIG_AMD, sizeof(sig)) == 0)
return detect_sev();
else if (memcmp(sig, CPUID_SIG_INTEL, sizeof(sig)) == 0)
return detect_tdx();
}
return CONFIDENTIAL_VIRTUALIZATION_NONE;
}
#elif defined(__s390x__)
static ConfidentialVirtualization detect_confidential_virtualization_impl(void) {
_cleanup_free_ char *s = NULL;
size_t readsize;
int r;
r = read_full_virtual_file("/sys/firmware/uv/prot_virt_guest", &s, &readsize);
if (r < 0) {
log_debug_errno(r, "Unable to read /sys/firmware/uv/prot_virt_guest: %m");
return CONFIDENTIAL_VIRTUALIZATION_NONE;
}
if (readsize >= 1 && s[0] == '1')
return CONFIDENTIAL_VIRTUALIZATION_PROTVIRT;
return CONFIDENTIAL_VIRTUALIZATION_NONE;
}
#else /* ! x86_64 */
static ConfidentialVirtualization detect_confidential_virtualization_impl(void) {
log_debug("No confidential virtualization detection on this architecture");
return CONFIDENTIAL_VIRTUALIZATION_NONE;
}
#endif /* ! x86_64 */
ConfidentialVirtualization detect_confidential_virtualization(void) {
static thread_local ConfidentialVirtualization cached_found = _CONFIDENTIAL_VIRTUALIZATION_INVALID;
if (cached_found == _CONFIDENTIAL_VIRTUALIZATION_INVALID)
cached_found = detect_confidential_virtualization_impl();
return cached_found;
}
static const char *const confidential_virtualization_table[_CONFIDENTIAL_VIRTUALIZATION_MAX] = {
[CONFIDENTIAL_VIRTUALIZATION_NONE] = "none",
[CONFIDENTIAL_VIRTUALIZATION_SEV] = "sev",
[CONFIDENTIAL_VIRTUALIZATION_SEV_ES] = "sev-es",
[CONFIDENTIAL_VIRTUALIZATION_SEV_SNP] = "sev-snp",
[CONFIDENTIAL_VIRTUALIZATION_TDX] = "tdx",
[CONFIDENTIAL_VIRTUALIZATION_PROTVIRT] = "protvirt",
};
DEFINE_STRING_TABLE_LOOKUP(confidential_virtualization, ConfidentialVirtualization);
|
