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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 #define _GNU_SOURCE /* for program_invocation_short_name */
14 #include <fcntl.h>
15 #include <stdio.h>
16 #include <stdlib.h>
17 #include <string.h>
18 #include <sys/ioctl.h>
19 
20 #include "test_util.h"
21 
22 #include "kvm_util.h"
23 #include "processor.h"
24 
25 #define VCPU_ID                  5
26 
test_cr4_feature_bit(struct kvm_vm * vm,struct kvm_sregs * orig,uint64_t feature_bit)27 static void test_cr4_feature_bit(struct kvm_vm *vm, struct kvm_sregs *orig,
28 				 uint64_t feature_bit)
29 {
30 	struct kvm_sregs sregs;
31 	int rc;
32 
33 	/* Skip the sub-test, the feature is supported. */
34 	if (orig->cr4 & feature_bit)
35 		return;
36 
37 	memcpy(&sregs, orig, sizeof(sregs));
38 	sregs.cr4 |= feature_bit;
39 
40 	rc = _vcpu_sregs_set(vm, VCPU_ID, &sregs);
41 	TEST_ASSERT(rc, "KVM allowed unsupported CR4 bit (0x%lx)", feature_bit);
42 
43 	/* Sanity check that KVM didn't change anything. */
44 	vcpu_sregs_get(vm, VCPU_ID, &sregs);
45 	TEST_ASSERT(!memcmp(&sregs, orig, sizeof(sregs)), "KVM modified sregs");
46 }
47 
calc_cr4_feature_bits(struct kvm_vm * vm)48 static uint64_t calc_cr4_feature_bits(struct kvm_vm *vm)
49 {
50 	struct kvm_cpuid_entry2 *cpuid_1, *cpuid_7;
51 	uint64_t cr4;
52 
53 	cpuid_1 = kvm_get_supported_cpuid_entry(1);
54 	cpuid_7 = kvm_get_supported_cpuid_entry(7);
55 
56 	cr4 = X86_CR4_VME | X86_CR4_PVI | X86_CR4_TSD | X86_CR4_DE |
57 	      X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE | X86_CR4_PGE |
58 	      X86_CR4_PCE | X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT;
59 	if (cpuid_7->ecx & CPUID_UMIP)
60 		cr4 |= X86_CR4_UMIP;
61 	if (cpuid_7->ecx & CPUID_LA57)
62 		cr4 |= X86_CR4_LA57;
63 	if (cpuid_1->ecx & CPUID_VMX)
64 		cr4 |= X86_CR4_VMXE;
65 	if (cpuid_1->ecx & CPUID_SMX)
66 		cr4 |= X86_CR4_SMXE;
67 	if (cpuid_7->ebx & CPUID_FSGSBASE)
68 		cr4 |= X86_CR4_FSGSBASE;
69 	if (cpuid_1->ecx & CPUID_PCID)
70 		cr4 |= X86_CR4_PCIDE;
71 	if (cpuid_1->ecx & CPUID_XSAVE)
72 		cr4 |= X86_CR4_OSXSAVE;
73 	if (cpuid_7->ebx & CPUID_SMEP)
74 		cr4 |= X86_CR4_SMEP;
75 	if (cpuid_7->ebx & CPUID_SMAP)
76 		cr4 |= X86_CR4_SMAP;
77 	if (cpuid_7->ecx & CPUID_PKU)
78 		cr4 |= X86_CR4_PKE;
79 
80 	return cr4;
81 }
82 
main(int argc,char * argv[])83 int main(int argc, char *argv[])
84 {
85 	struct kvm_sregs sregs;
86 	struct kvm_vm *vm;
87 	uint64_t cr4;
88 	int rc;
89 
90 	/* Tell stdout not to buffer its content */
91 	setbuf(stdout, NULL);
92 
93 	/*
94 	 * Create a dummy VM, specifically to avoid doing KVM_SET_CPUID2, and
95 	 * use it to verify all supported CR4 bits can be set prior to defining
96 	 * the vCPU model, i.e. without doing KVM_SET_CPUID2.
97 	 */
98 	vm = vm_create(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES, O_RDWR);
99 	vm_vcpu_add(vm, VCPU_ID);
100 
101 	vcpu_sregs_get(vm, VCPU_ID, &sregs);
102 
103 	sregs.cr4 |= calc_cr4_feature_bits(vm);
104 	cr4 = sregs.cr4;
105 
106 	rc = _vcpu_sregs_set(vm, VCPU_ID, &sregs);
107 	TEST_ASSERT(!rc, "Failed to set supported CR4 bits (0x%lx)", cr4);
108 
109 	vcpu_sregs_get(vm, VCPU_ID, &sregs);
110 	TEST_ASSERT(sregs.cr4 == cr4, "sregs.CR4 (0x%llx) != CR4 (0x%lx)",
111 		    sregs.cr4, cr4);
112 
113 	/* Verify all unsupported features are rejected by KVM. */
114 	test_cr4_feature_bit(vm, &sregs, X86_CR4_UMIP);
115 	test_cr4_feature_bit(vm, &sregs, X86_CR4_LA57);
116 	test_cr4_feature_bit(vm, &sregs, X86_CR4_VMXE);
117 	test_cr4_feature_bit(vm, &sregs, X86_CR4_SMXE);
118 	test_cr4_feature_bit(vm, &sregs, X86_CR4_FSGSBASE);
119 	test_cr4_feature_bit(vm, &sregs, X86_CR4_PCIDE);
120 	test_cr4_feature_bit(vm, &sregs, X86_CR4_OSXSAVE);
121 	test_cr4_feature_bit(vm, &sregs, X86_CR4_SMEP);
122 	test_cr4_feature_bit(vm, &sregs, X86_CR4_SMAP);
123 	test_cr4_feature_bit(vm, &sregs, X86_CR4_PKE);
124 	kvm_vm_free(vm);
125 
126 	/* Create a "real" VM and verify APIC_BASE can be set. */
127 	vm = vm_create_default(VCPU_ID, 0, NULL);
128 
129 	vcpu_sregs_get(vm, VCPU_ID, &sregs);
130 	sregs.apic_base = 1 << 10;
131 	rc = _vcpu_sregs_set(vm, VCPU_ID, &sregs);
132 	TEST_ASSERT(rc, "Set IA32_APIC_BASE to %llx (invalid)",
133 		    sregs.apic_base);
134 	sregs.apic_base = 1 << 11;
135 	rc = _vcpu_sregs_set(vm, VCPU_ID, &sregs);
136 	TEST_ASSERT(!rc, "Couldn't set IA32_APIC_BASE to %llx (valid)",
137 		    sregs.apic_base);
138 
139 	kvm_vm_free(vm);
140 
141 	return 0;
142 }
143