--- /dev/null
+/*
+ * kvm_create_max_vcpus
+ *
+ * Copyright (C) 2019, Google LLC.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * Test for KVM_CAP_MAX_VCPUS and KVM_CAP_MAX_VCPU_ID.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "test_util.h"
+
+#include "kvm_util.h"
+#include "asm/kvm.h"
+#include "linux/kvm.h"
+
+void test_vcpu_creation(int first_vcpu_id, int num_vcpus)
+{
+ struct kvm_vm *vm;
+ int i;
+
+ printf("Testing creating %d vCPUs, with IDs %d...%d.\n",
+ num_vcpus, first_vcpu_id, first_vcpu_id + num_vcpus - 1);
+
+ vm = vm_create(VM_MODE_P52V48_4K, DEFAULT_GUEST_PHY_PAGES, O_RDWR);
+
+ for (i = 0; i < num_vcpus; i++) {
+ int vcpu_id = first_vcpu_id + i;
+
+ /* This asserts that the vCPU was created. */
+ vm_vcpu_add(vm, vcpu_id, 0, 0);
+ }
+
+ kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+ int kvm_max_vcpu_id = kvm_check_cap(KVM_CAP_MAX_VCPU_ID);
+ int kvm_max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
+
+ printf("KVM_CAP_MAX_VCPU_ID: %d\n", kvm_max_vcpu_id);
+ printf("KVM_CAP_MAX_VCPUS: %d\n", kvm_max_vcpus);
+
+ /*
+ * Upstream KVM prior to 4.8 does not support KVM_CAP_MAX_VCPU_ID.
+ * Userspace is supposed to use KVM_CAP_MAX_VCPUS as the maximum ID
+ * in this case.
+ */
+ if (!kvm_max_vcpu_id)
+ kvm_max_vcpu_id = kvm_max_vcpus;
+
+ TEST_ASSERT(kvm_max_vcpu_id >= kvm_max_vcpus,
+ "KVM_MAX_VCPU_ID (%d) must be at least as large as KVM_MAX_VCPUS (%d).",
+ kvm_max_vcpu_id, kvm_max_vcpus);
+
+ test_vcpu_creation(0, kvm_max_vcpus);
+
+ if (kvm_max_vcpu_id > kvm_max_vcpus)
+ test_vcpu_creation(
+ kvm_max_vcpu_id - kvm_max_vcpus, kvm_max_vcpus);
+
+ return 0;
+}