KVM: selftests: Move vCPU thread creation and joining to common helpers

Move vCPU thread creation and joining to common helper functions. This
is in preparation for the next commit which ensures that all vCPU
threads are fully created before entering guest mode on any one
vCPU.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Message-Id: <20211111001257.1446428-3-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c
index 77f9eb5667c9..d646477ed16a 100644
--- a/tools/testing/selftests/kvm/lib/perf_test_util.c
+++ b/tools/testing/selftests/kvm/lib/perf_test_util.c
@@ -16,6 +16,20 @@ struct perf_test_args perf_test_args;
  */
 static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
 
+struct vcpu_thread {
+	/* The id of the vCPU. */
+	int vcpu_id;
+
+	/* The pthread backing the vCPU. */
+	pthread_t thread;
+};
+
+/* The vCPU threads involved in this test. */
+static struct vcpu_thread vcpu_threads[KVM_MAX_VCPUS];
+
+/* The function run by each vCPU thread, as provided by the test. */
+static void (*vcpu_thread_fn)(struct perf_test_vcpu_args *);
+
 /*
  * Continuously write to the first 8 bytes of each page in the
  * specified region.
@@ -177,3 +191,35 @@ void perf_test_set_wr_fract(struct kvm_vm *vm, int wr_fract)
 	perf_test_args.wr_fract = wr_fract;
 	sync_global_to_guest(vm, perf_test_args);
 }
+
+static void *vcpu_thread_main(void *data)
+{
+	struct vcpu_thread *vcpu = data;
+
+	vcpu_thread_fn(&perf_test_args.vcpu_args[vcpu->vcpu_id]);
+
+	return NULL;
+}
+
+void perf_test_start_vcpu_threads(int vcpus, void (*vcpu_fn)(struct perf_test_vcpu_args *))
+{
+	int vcpu_id;
+
+	vcpu_thread_fn = vcpu_fn;
+
+	for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
+		struct vcpu_thread *vcpu = &vcpu_threads[vcpu_id];
+
+		vcpu->vcpu_id = vcpu_id;
+
+		pthread_create(&vcpu->thread, NULL, vcpu_thread_main, vcpu);
+	}
+}
+
+void perf_test_join_vcpu_threads(int vcpus)
+{
+	int vcpu_id;
+
+	for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++)
+		pthread_join(vcpu_threads[vcpu_id].thread, NULL);
+}