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KVM: x86: Test case for TSC scaling and offset sync

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Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20220225145304.36166-4-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
David Woodhouse 2022-02-25 14:53:04 +00:00 committed by Paolo Bonzini
parent 741e511b42
commit e467b0de82
2 changed files with 120 additions and 0 deletions
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1
tools/testing/selftests/kvm/Makefile
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@ -66,6 +66,7 @@ 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

119
tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c Normal file
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@ -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;
}