1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * KVM_SET_SREGS tests
4 *
5 * Copyright (C) 2018, Google LLC.
6 *
7 * This is a regression test for the bug fixed by the following commit:
8 * d3802286fa0f ("kvm: x86: Disallow illegal IA32_APIC_BASE MSR values")
9 *
10 * That bug allowed a user-mode program that called the KVM_SET_SREGS
11 * ioctl to put a VCPU's local APIC into an invalid state.
12 */
13 #include <fcntl.h>
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <string.h>
17 #include <sys/ioctl.h>
18
19 #include "test_util.h"
20
21 #include "kvm_util.h"
22 #include "processor.h"
23
24 #define TEST_INVALID_CR_BIT(vcpu, cr, orig, bit) \
25 do { \
26 struct kvm_sregs new; \
27 int rc; \
28 \
29 /* Skip the sub-test, the feature/bit is supported. */ \
30 if (orig.cr & bit) \
31 break; \
32 \
33 memcpy(&new, &orig, sizeof(sregs)); \
34 new.cr |= bit; \
35 \
36 rc = _vcpu_sregs_set(vcpu, &new); \
37 TEST_ASSERT(rc, "KVM allowed invalid " #cr " bit (0x%lx)", bit); \
38 \
39 /* Sanity check that KVM didn't change anything. */ \
40 vcpu_sregs_get(vcpu, &new); \
41 TEST_ASSERT(!memcmp(&new, &orig, sizeof(new)), "KVM modified sregs"); \
42 } while (0)
43
44 #define KVM_ALWAYS_ALLOWED_CR4 (X86_CR4_VME | X86_CR4_PVI | X86_CR4_TSD | \
45 X86_CR4_DE | X86_CR4_PSE | X86_CR4_PAE | \
46 X86_CR4_MCE | X86_CR4_PGE | X86_CR4_PCE | \
47 X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT)
48
calc_supported_cr4_feature_bits(void)49 static uint64_t calc_supported_cr4_feature_bits(void)
50 {
51 uint64_t cr4 = KVM_ALWAYS_ALLOWED_CR4;
52
53 if (kvm_cpu_has(X86_FEATURE_UMIP))
54 cr4 |= X86_CR4_UMIP;
55 if (kvm_cpu_has(X86_FEATURE_LA57))
56 cr4 |= X86_CR4_LA57;
57 if (kvm_cpu_has(X86_FEATURE_VMX))
58 cr4 |= X86_CR4_VMXE;
59 if (kvm_cpu_has(X86_FEATURE_SMX))
60 cr4 |= X86_CR4_SMXE;
61 if (kvm_cpu_has(X86_FEATURE_FSGSBASE))
62 cr4 |= X86_CR4_FSGSBASE;
63 if (kvm_cpu_has(X86_FEATURE_PCID))
64 cr4 |= X86_CR4_PCIDE;
65 if (kvm_cpu_has(X86_FEATURE_XSAVE))
66 cr4 |= X86_CR4_OSXSAVE;
67 if (kvm_cpu_has(X86_FEATURE_SMEP))
68 cr4 |= X86_CR4_SMEP;
69 if (kvm_cpu_has(X86_FEATURE_SMAP))
70 cr4 |= X86_CR4_SMAP;
71 if (kvm_cpu_has(X86_FEATURE_PKU))
72 cr4 |= X86_CR4_PKE;
73
74 return cr4;
75 }
76
test_cr_bits(struct kvm_vcpu * vcpu,uint64_t cr4)77 static void test_cr_bits(struct kvm_vcpu *vcpu, uint64_t cr4)
78 {
79 struct kvm_sregs sregs;
80 int rc, i;
81
82 vcpu_sregs_get(vcpu, &sregs);
83 sregs.cr0 &= ~(X86_CR0_CD | X86_CR0_NW);
84 sregs.cr4 |= cr4;
85 rc = _vcpu_sregs_set(vcpu, &sregs);
86 TEST_ASSERT(!rc, "Failed to set supported CR4 bits (0x%lx)", cr4);
87
88 TEST_ASSERT(!!(sregs.cr4 & X86_CR4_OSXSAVE) ==
89 (vcpu->cpuid && vcpu_cpuid_has(vcpu, X86_FEATURE_OSXSAVE)),
90 "KVM didn't %s OSXSAVE in CPUID as expected",
91 (sregs.cr4 & X86_CR4_OSXSAVE) ? "set" : "clear");
92
93 TEST_ASSERT(!!(sregs.cr4 & X86_CR4_PKE) ==
94 (vcpu->cpuid && vcpu_cpuid_has(vcpu, X86_FEATURE_OSPKE)),
95 "KVM didn't %s OSPKE in CPUID as expected",
96 (sregs.cr4 & X86_CR4_PKE) ? "set" : "clear");
97
98 vcpu_sregs_get(vcpu, &sregs);
99 TEST_ASSERT(sregs.cr4 == cr4, "sregs.CR4 (0x%llx) != CR4 (0x%lx)",
100 sregs.cr4, cr4);
101
102 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_UMIP);
103 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_LA57);
104 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_VMXE);
105 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_SMXE);
106 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_FSGSBASE);
107 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_PCIDE);
108 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_OSXSAVE);
109 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_SMEP);
110 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_SMAP);
111 TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_PKE);
112
113 for (i = 32; i < 64; i++)
114 TEST_INVALID_CR_BIT(vcpu, cr0, sregs, BIT(i));
115
116 /* NW without CD is illegal, as is PG without PE. */
117 TEST_INVALID_CR_BIT(vcpu, cr0, sregs, X86_CR0_NW);
118 TEST_INVALID_CR_BIT(vcpu, cr0, sregs, X86_CR0_PG);
119 }
120
main(int argc,char * argv[])121 int main(int argc, char *argv[])
122 {
123 struct kvm_sregs sregs;
124 struct kvm_vcpu *vcpu;
125 struct kvm_vm *vm;
126 int rc;
127
128 /*
129 * Create a dummy VM, specifically to avoid doing KVM_SET_CPUID2, and
130 * use it to verify KVM enforces guest CPUID even if *userspace* never
131 * sets CPUID.
132 */
133 vm = vm_create_barebones();
134 vcpu = __vm_vcpu_add(vm, 0);
135 test_cr_bits(vcpu, KVM_ALWAYS_ALLOWED_CR4);
136 kvm_vm_free(vm);
137
138 /* Create a "real" VM with a fully populated guest CPUID and verify
139 * APIC_BASE and all supported CR4 can be set.
140 */
141 vm = vm_create_with_one_vcpu(&vcpu, NULL);
142
143 vcpu_sregs_get(vcpu, &sregs);
144 sregs.apic_base = 1 << 10;
145 rc = _vcpu_sregs_set(vcpu, &sregs);
146 TEST_ASSERT(rc, "Set IA32_APIC_BASE to %llx (invalid)",
147 sregs.apic_base);
148 sregs.apic_base = 1 << 11;
149 rc = _vcpu_sregs_set(vcpu, &sregs);
150 TEST_ASSERT(!rc, "Couldn't set IA32_APIC_BASE to %llx (valid)",
151 sregs.apic_base);
152
153 test_cr_bits(vcpu, calc_supported_cr4_feature_bits());
154
155 kvm_vm_free(vm);
156
157 return 0;
158 }
159