On 11/19/22 5:15 AM, Oliver Upton wrote:

Signal that a test run is complete through perf_test_args instead of having tests open code a similar solution. Ensure that the field resets to false at the beginning of a test run as the structure is reused between test runs, eliminating a couple of bugs:

access_tracking_perf_test hangs indefinitely on a subsequent test run, as 'done' remains true. The bug doesn't amount to much right now, as x86 supports a single guest mode. However, this is a precondition of enabling the test for other architectures with >1 guest mode, like arm64.

memslot_modification_stress_test has the exact opposite problem, where subsequent test runs complete immediately as 'run_vcpus' remains false.

Co-developed-by: Sean Christopherson seanjc@google.com Signed-off-by: Sean Christopherson seanjc@google.com [oliver: added commit message, preserve spin_wait_for_next_iteration()] Signed-off-by: Oliver Upton oliver.upton@linux.dev

---

tools/testing/selftests/kvm/access_tracking_perf_test.c | 8 +------- tools/testing/selftests/kvm/include/perf_test_util.h | 3 +++ tools/testing/selftests/kvm/lib/perf_test_util.c | 3 +++ .../selftests/kvm/memslot_modification_stress_test.c | 6 +----- 4 files changed, 8 insertions(+), 12 deletions(-)

Reviewed-by: Gavin Shan gshan@redhat.com

diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c index 76c583a07ea2..942370d57392 100644 --- a/tools/testing/selftests/kvm/access_tracking_perf_test.c +++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c @@ -58,9 +58,6 @@ static enum { ITERATION_MARK_IDLE, } iteration_work; -/* Set to true when vCPU threads should exit. */ -static bool done;

• /* The iteration that was last completed by each vCPU. */ static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];

@@ -211,7 +208,7 @@ static bool spin_wait_for_next_iteration(int *current_iteration) int last_iteration = *current_iteration; do {

• if (READ_ONCE(done))
  

• if (READ_ONCE(perf_test_args.stop_vcpus))
  return false;
  

*current_iteration = READ_ONCE(iteration); @@ -321,9 +318,6 @@ static void run_test(enum vm_guest_mode mode, void *arg) mark_memory_idle(vm, nr_vcpus); access_memory(vm, nr_vcpus, ACCESS_READ, "Reading from idle memory");

• /* Set done to signal the vCPU threads to exit */
• done = true;
• perf_test_join_vcpu_threads(nr_vcpus); perf_test_destroy_vm(vm); }

diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h index eaa88df0555a..536d7c3c3f14 100644 --- a/tools/testing/selftests/kvm/include/perf_test_util.h +++ b/tools/testing/selftests/kvm/include/perf_test_util.h @@ -40,6 +40,9 @@ struct perf_test_args { /* Run vCPUs in L2 instead of L1, if the architecture supports it. */ bool nested;

• /* Test is done, stop running vCPUs. */
• bool stop_vcpus;
• struct perf_test_vcpu_args vcpu_args[KVM_MAX_VCPUS]; };

diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c index 9618b37c66f7..ee3f499ccbd2 100644 --- a/tools/testing/selftests/kvm/lib/perf_test_util.c +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c @@ -267,6 +267,7 @@ void perf_test_start_vcpu_threads(int nr_vcpus, vcpu_thread_fn = vcpu_fn; WRITE_ONCE(all_vcpu_threads_running, false);

• WRITE_ONCE(perf_test_args.stop_vcpus, false);

for (i = 0; i < nr_vcpus; i++) { struct vcpu_thread *vcpu = &vcpu_threads[i]; @@ -289,6 +290,8 @@ void perf_test_join_vcpu_threads(int nr_vcpus) { int i;

• WRITE_ONCE(perf_test_args.stop_vcpus, true);
• for (i = 0; i < nr_vcpus; i++) pthread_join(vcpu_threads[i].thread, NULL); }

diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c index bb1d17a1171b..3a5e4518307c 100644 --- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c +++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c @@ -34,8 +34,6 @@ static int nr_vcpus = 1; static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE; -static bool run_vcpus = true;

• static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args) { struct kvm_vcpu *vcpu = vcpu_args->vcpu;

@@ -45,7 +43,7 @@ static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args) run = vcpu->run; /* Let the guest access its memory until a stop signal is received */

• while (READ_ONCE(run_vcpus)) {

• while (!READ_ONCE(perf_test_args.stop_vcpus)) { ret = _vcpu_run(vcpu); TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);

@@ -110,8 +108,6 @@ static void run_test(enum vm_guest_mode mode, void *arg) add_remove_memslot(vm, p->memslot_modification_delay, p->nr_memslot_modifications);

• run_vcpus = false;
• perf_test_join_vcpu_threads(nr_vcpus); pr_info("All vCPU threads joined\n");