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
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2018, Google LLC.
*
* IA32_TSC_ADJUST test
*
* According to the SDM, "if an execution of WRMSR to the
* IA32_TIME_STAMP_COUNTER MSR adds (or subtracts) value X from the TSC,
* the logical processor also adds (or subtracts) value X from the
* IA32_TSC_ADJUST MSR.
*
* Note that when L1 doesn't intercept writes to IA32_TSC, a
* WRMSR(IA32_TSC) from L2 sets L1's TSC value, not L2's perceived TSC
* value.
*
* This test verifies that this unusual case is handled correctly.
*/
#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
#include "vmx.h"
#include "svm_util.h"
#include <string.h>
#include <sys/ioctl.h>
#include "kselftest.h"
#ifndef MSR_IA32_TSC_ADJUST
#define MSR_IA32_TSC_ADJUST 0x3b
#endif
#define TSC_ADJUST_VALUE (1ll << 32)
#define TSC_OFFSET_VALUE -(1ll << 48)
#define L2_GUEST_STACK_SIZE 64
enum {
PORT_ABORT = 0x1000,
PORT_REPORT,
PORT_DONE,
};
enum {
VMXON_PAGE = 0,
VMCS_PAGE,
MSR_BITMAP_PAGE,
NUM_VMX_PAGES,
};
/* The virtual machine object. */
static struct kvm_vm *vm;
static void check_ia32_tsc_adjust(int64_t max)
{
int64_t adjust;
adjust = rdmsr(MSR_IA32_TSC_ADJUST);
GUEST_SYNC(adjust);
GUEST_ASSERT(adjust <= max);
}
static void l2_guest_code(void)
{
uint64_t l1_tsc = rdtsc() - TSC_OFFSET_VALUE;
wrmsr(MSR_IA32_TSC, l1_tsc - TSC_ADJUST_VALUE);
check_ia32_tsc_adjust(-2 * TSC_ADJUST_VALUE);
/* Exit to L1 */
__asm__ __volatile__("vmcall");
}
static void l1_guest_code(void *data)
{
unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
/* Set TSC from L1 and make sure TSC_ADJUST is updated correctly */
GUEST_ASSERT(rdtsc() < TSC_ADJUST_VALUE);
wrmsr(MSR_IA32_TSC, rdtsc() - TSC_ADJUST_VALUE);
check_ia32_tsc_adjust(-1 * TSC_ADJUST_VALUE);
/*
* Run L2 with TSC_OFFSET. L2 will write to TSC, and L1 is not
* intercepting the write so it should update L1's TSC_ADJUST.
*/
if (this_cpu_has(X86_FEATURE_VMX)) {
struct vmx_pages *vmx_pages = data;
uint32_t control;
GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
GUEST_ASSERT(load_vmcs(vmx_pages));
prepare_vmcs(vmx_pages, l2_guest_code,
&l2_guest_stack[L2_GUEST_STACK_SIZE]);
control = vmreadz(CPU_BASED_VM_EXEC_CONTROL);
control |= CPU_BASED_USE_MSR_BITMAPS | CPU_BASED_USE_TSC_OFFSETTING;
vmwrite(CPU_BASED_VM_EXEC_CONTROL, control);
vmwrite(TSC_OFFSET, TSC_OFFSET_VALUE);
GUEST_ASSERT(!vmlaunch());
GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
} else {
struct svm_test_data *svm = data;
generic_svm_setup(svm, l2_guest_code,
&l2_guest_stack[L2_GUEST_STACK_SIZE]);
svm->vmcb->control.tsc_offset = TSC_OFFSET_VALUE;
run_guest(svm->vmcb, svm->vmcb_gpa);
GUEST_ASSERT(svm->vmcb->control.exit_code == SVM_EXIT_VMMCALL);
}
check_ia32_tsc_adjust(-2 * TSC_ADJUST_VALUE);
GUEST_DONE();
}
static void report(int64_t val)
{
pr_info("IA32_TSC_ADJUST is %ld (%lld * TSC_ADJUST_VALUE + %lld).\n",
val, val / TSC_ADJUST_VALUE, val % TSC_ADJUST_VALUE);
}
int main(int argc, char *argv[])
{
vm_vaddr_t nested_gva;
struct kvm_vcpu *vcpu;
TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX) ||
kvm_cpu_has(X86_FEATURE_SVM));
vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
if (kvm_cpu_has(X86_FEATURE_VMX))
vcpu_alloc_vmx(vm, &nested_gva);
else
vcpu_alloc_svm(vm, &nested_gva);
vcpu_args_set(vcpu, 1, nested_gva);
for (;;) {
struct ucall uc;
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
switch (get_ucall(vcpu, &uc)) {
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
/* NOT REACHED */
case UCALL_SYNC:
report(uc.args[1]);
break;
case UCALL_DONE:
goto done;
default:
TEST_FAIL("Unknown ucall %lu", uc.cmd);
}
}
done:
kvm_vm_free(vm);
return 0;
}
|
