1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * svm_vmcall_test
4  *
5  * Copyright © 2021 Amazon.com, Inc. or its affiliates.
6  *
7  * Xen shared_info / pvclock testing
8  */
9 
10 #include "test_util.h"
11 #include "kvm_util.h"
12 #include "processor.h"
13 
14 #include <stdint.h>
15 #include <time.h>
16 #include <sched.h>
17 #include <signal.h>
18 #include <pthread.h>
19 
20 #define NR_TEST_VCPUS 20
21 
22 static struct kvm_vm *vm;
23 pthread_spinlock_t create_lock;
24 
25 #define TEST_TSC_KHZ    2345678UL
26 #define TEST_TSC_OFFSET 200000000
27 
28 uint64_t tsc_sync;
29 static void guest_code(void)
30 {
31 	uint64_t start_tsc, local_tsc, tmp;
32 
33 	start_tsc = rdtsc();
34 	do {
35 		tmp = READ_ONCE(tsc_sync);
36 		local_tsc = rdtsc();
37 		WRITE_ONCE(tsc_sync, local_tsc);
38 		if (unlikely(local_tsc < tmp))
39 			GUEST_SYNC_ARGS(0, local_tsc, tmp, 0, 0);
40 
41 	} while (local_tsc - start_tsc < 5000 * TEST_TSC_KHZ);
42 
43 	GUEST_DONE();
44 }
45 
46 
47 static void *run_vcpu(void *_cpu_nr)
48 {
49 	unsigned long vcpu_id = (unsigned long)_cpu_nr;
50 	unsigned long failures = 0;
51 	static bool first_cpu_done;
52 	struct kvm_vcpu *vcpu;
53 
54 	/* The kernel is fine, but vm_vcpu_add() needs locking */
55 	pthread_spin_lock(&create_lock);
56 
57 	vcpu = vm_vcpu_add(vm, vcpu_id, guest_code);
58 
59 	if (!first_cpu_done) {
60 		first_cpu_done = true;
61 		vcpu_set_msr(vcpu, MSR_IA32_TSC, TEST_TSC_OFFSET);
62 	}
63 
64 	pthread_spin_unlock(&create_lock);
65 
66 	for (;;) {
67                 struct ucall uc;
68 
69 		vcpu_run(vcpu);
70 		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
71 
72 		switch (get_ucall(vcpu, &uc)) {
73                 case UCALL_DONE:
74 			goto out;
75 
76                 case UCALL_SYNC:
77 			printf("Guest %d sync %lx %lx %ld\n", vcpu->id,
78 			       uc.args[2], uc.args[3], uc.args[2] - uc.args[3]);
79 			failures++;
80 			break;
81 
82                 default:
83                         TEST_FAIL("Unknown ucall %lu", uc.cmd);
84 		}
85 	}
86  out:
87 	return (void *)failures;
88 }
89 
90 int main(int argc, char *argv[])
91 {
92 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_VM_TSC_CONTROL));
93 
94 	vm = vm_create(NR_TEST_VCPUS);
95 	vm_ioctl(vm, KVM_SET_TSC_KHZ, (void *) TEST_TSC_KHZ);
96 
97 	pthread_spin_init(&create_lock, PTHREAD_PROCESS_PRIVATE);
98 	pthread_t cpu_threads[NR_TEST_VCPUS];
99 	unsigned long cpu;
100 	for (cpu = 0; cpu < NR_TEST_VCPUS; cpu++)
101 		pthread_create(&cpu_threads[cpu], NULL, run_vcpu, (void *)cpu);
102 
103 	unsigned long failures = 0;
104 	for (cpu = 0; cpu < NR_TEST_VCPUS; cpu++) {
105 		void *this_cpu_failures;
106 		pthread_join(cpu_threads[cpu], &this_cpu_failures);
107 		failures += (unsigned long)this_cpu_failures;
108 	}
109 
110 	TEST_ASSERT(!failures, "TSC sync failed");
111 	pthread_spin_destroy(&create_lock);
112 	kvm_vm_free(vm);
113 	return 0;
114 }
115