From: David Woodhouse <dwmw@xxxxxxxxxxxx>
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/x86_64/tsc_scaling_sync.c | 119 ++++++++++++++++++
2 files changed, 120 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 06c3a4602bcc..33b57f8c6251 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -65,6 +65,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/state_test
TEST_GEN_PROGS_x86_64 += x86_64/vmx_preemption_timer_test
TEST_GEN_PROGS_x86_64 += x86_64/svm_vmcall_test
TEST_GEN_PROGS_x86_64 += x86_64/svm_int_ctl_test
+TEST_GEN_PROGS_x86_64 += x86_64/tsc_scaling_sync
TEST_GEN_PROGS_x86_64 += x86_64/sync_regs_test
TEST_GEN_PROGS_x86_64 += x86_64/userspace_io_test
TEST_GEN_PROGS_x86_64 += x86_64/userspace_msr_exit_test
diff --git a/tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c b/tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c
new file mode 100644
index 000000000000..f0083d8cfe98
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * svm_vmcall_test
+ *
+ * Copyright © 2021 Amazon.com, Inc. or its affiliates.
+ *
+ * Xen shared_info / pvclock testing
+ */
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+#include <stdint.h>
+#include <time.h>
+#include <sched.h>
+#include <signal.h>
+#include <pthread.h>
+
+#define NR_TEST_VCPUS 20
+
+static struct kvm_vm *vm;
+pthread_spinlock_t create_lock;
+
+#define TEST_TSC_KHZ 2345678UL
+#define TEST_TSC_OFFSET 200000000
+
+uint64_t tsc_sync;
+static void guest_code(void)
+{
+ uint64_t start_tsc, local_tsc, tmp;
+
+ start_tsc = rdtsc();
+ do {
+ tmp = READ_ONCE(tsc_sync);
+ local_tsc = rdtsc();
+ WRITE_ONCE(tsc_sync, local_tsc);
+ if (unlikely(local_tsc < tmp))
+ GUEST_SYNC_ARGS(0, local_tsc, tmp, 0, 0);
+
+ } while (local_tsc - start_tsc < 5000 * TEST_TSC_KHZ);
+
+ GUEST_DONE();
+}
+
+
+static void *run_vcpu(void *_cpu_nr)
+{
+ unsigned long cpu = (unsigned long)_cpu_nr;
+ unsigned long failures = 0;
+ static bool first_cpu_done;
+
+ /* The kernel is fine, but vm_vcpu_add_default() needs locking */
+ pthread_spin_lock(&create_lock);
+
+ vm_vcpu_add_default(vm, cpu, guest_code);
+
+ if (!first_cpu_done) {
+ first_cpu_done = true;
+ vcpu_set_msr(vm, cpu, MSR_IA32_TSC, TEST_TSC_OFFSET);
+ }
+
+ pthread_spin_unlock(&create_lock);
+
+ for (;;) {
+ volatile struct kvm_run *run = vcpu_state(vm, cpu);
+ struct ucall uc;
+
+ vcpu_run(vm, cpu);
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
+ run->exit_reason,
+ exit_reason_str(run->exit_reason));
+
+ switch (get_ucall(vm, cpu, &uc)) {
+ case UCALL_DONE:
+ goto out;
+
+ case UCALL_SYNC:
+ printf("Guest %ld sync %lx %lx %ld\n", cpu, uc.args[2], uc.args[3], uc.args[2] - uc.args[3]);
+ failures++;
+ break;
+
+ default:
+ TEST_FAIL("Unknown ucall %lu", uc.cmd);
+ }
+ }
+ out:
+ return (void *)failures;
+}
+
+int main(int argc, char *argv[])
+{
+ if (!kvm_check_cap(KVM_CAP_VM_TSC_CONTROL)) {
+ print_skip("KVM_CAP_VM_TSC_CONTROL not available");
+ exit(KSFT_SKIP);
+ }
+
+ vm = vm_create_default_with_vcpus(0, DEFAULT_STACK_PGS * NR_TEST_VCPUS, 0, guest_code, NULL);
+ vm_ioctl(vm, KVM_SET_TSC_KHZ, (void *) TEST_TSC_KHZ);
+
+ pthread_spin_init(&create_lock, PTHREAD_PROCESS_PRIVATE);
+ pthread_t cpu_threads[NR_TEST_VCPUS];
+ unsigned long cpu;
+ for (cpu = 0; cpu < NR_TEST_VCPUS; cpu++)
+ pthread_create(&cpu_threads[cpu], NULL, run_vcpu, (void *)cpu);
+
+ unsigned long failures = 0;
+ for (cpu = 0; cpu < NR_TEST_VCPUS; cpu++) {
+ void *this_cpu_failures;
+ pthread_join(cpu_threads[cpu], &this_cpu_failures);
+ failures += (unsigned long)this_cpu_failures;
+ }
+
+ TEST_ASSERT(!failures, "TSC sync failed");
+ pthread_spin_destroy(&create_lock);
+ kvm_vm_free(vm);
+ return 0;
+}
--
2.33.1
