diff options
Diffstat (limited to 'tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c')
-rw-r--r-- | tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c | 110 |
1 files changed, 110 insertions, 0 deletions
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 0000000000..59c7304f80 --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c @@ -0,0 +1,110 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright © 2021 Amazon.com, Inc. or its affiliates. + */ + +#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 vcpu_id = (unsigned long)_cpu_nr; + unsigned long failures = 0; + static bool first_cpu_done; + struct kvm_vcpu *vcpu; + + /* The kernel is fine, but vm_vcpu_add() needs locking */ + pthread_spin_lock(&create_lock); + + vcpu = vm_vcpu_add(vm, vcpu_id, guest_code); + + if (!first_cpu_done) { + first_cpu_done = true; + vcpu_set_msr(vcpu, MSR_IA32_TSC, TEST_TSC_OFFSET); + } + + pthread_spin_unlock(&create_lock); + + for (;;) { + struct ucall uc; + + vcpu_run(vcpu); + TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO); + + switch (get_ucall(vcpu, &uc)) { + case UCALL_DONE: + goto out; + + case UCALL_SYNC: + printf("Guest %d sync %lx %lx %ld\n", vcpu->id, + 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[]) +{ + TEST_REQUIRE(kvm_has_cap(KVM_CAP_VM_TSC_CONTROL)); + + vm = vm_create(NR_TEST_VCPUS); + 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; +} |