AArch64 EL2 hypervisor for QEMU virt that boots at EL2
Introduce policy lattice validation for privileged register classes
author
vm.fail
date
(May 13, 2026, 10:24 AM UTC)
commit
e1ec3739
e1ec3739dbf451eb215246bd77f4e113576ac213
parent
1bb0138e
1bb0138eb9373a66d09eeb175f300a9892983f46
vm.fail
date
(May 13, 2026, 10:24 AM UTC)
commit
e1ec3739
e1ec3739dbf451eb215246bd77f4e113576ac213
parent
1bb0138e
1bb0138eb9373a66d09eeb175f300a9892983f46
+49
+49
core/policy.c
+49
core/policy.c
···
54
54
static enum policy_profile g_profile;
55
55
static struct policy_entry g_effective_entry;
56
56
57
+
static bool policy_action_valid(enum policy_action action)
58
+
{
59
+
return action == POLICY_ALLOW_NATIVE ||
60
+
action == POLICY_EMULATE_READ ||
61
+
action == POLICY_EMULATE_WRITE ||
62
+
action == POLICY_WRITE_MASK ||
63
+
action == POLICY_DENY_SKIP ||
64
+
action == POLICY_DENY_UNDEF ||
65
+
action == POLICY_PAUSE ||
66
+
action == POLICY_PANIC;
67
+
}
68
+
69
+
static bool policy_class_valid(enum policy_class access_class)
70
+
{
71
+
return access_class == POLICY_CLASS_ID ||
72
+
access_class == POLICY_CLASS_MMU ||
73
+
access_class == POLICY_CLASS_TIMER ||
74
+
access_class == POLICY_CLASS_THREAD ||
75
+
access_class == POLICY_CLASS_PMU ||
76
+
access_class == POLICY_CLASS_DEBUG ||
77
+
access_class == POLICY_CLASS_EL2_EL3 ||
78
+
access_class == POLICY_CLASS_MISC;
79
+
}
80
+
81
+
static bool policy_lattice_valid(const struct policy_entry *entry)
82
+
{
83
+
if (entry == (const struct policy_entry *)0 || entry->name == (const char *)0) {
84
+
return false;
85
+
}
86
+
if (!policy_class_valid(entry->access_class) ||
87
+
!policy_action_valid(entry->read_policy) ||
88
+
!policy_action_valid(entry->write_policy)) {
89
+
return false;
90
+
}
91
+
if (entry->access_class == POLICY_CLASS_EL2_EL3 &&
92
+
(entry->read_policy != POLICY_DENY_UNDEF ||
93
+
entry->write_policy != POLICY_DENY_UNDEF)) {
94
+
return false;
95
+
}
96
+
if (entry->write_policy == POLICY_WRITE_MASK && entry->writable_mask == 0u &&
97
+
entry->access_class != POLICY_CLASS_DEBUG) {
98
+
return false;
99
+
}
100
+
return true;
101
+
}
102
+
57
103
void policy_init(void)
58
104
{
59
105
g_profile = POLICY_PROFILE_STRICT;
···
268
314
enum policy_profile saved = g_profile;
269
315
bool profile_ok;
270
316
for (uint32_t i = 0; i < HV_ARRAY_SIZE(g_policy); i++) {
317
+
if (!policy_lattice_valid(&g_policy[i])) {
318
+
return false;
319
+
}
271
320
if (sysreg_policy_lookup(g_policy[i].key) != &g_policy[i]) {
272
321
return false;
273
322
}