1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * kvm_create_max_vcpus
4  *
5  * Copyright (C) 2019, Google LLC.
6  *
7  * Test for KVM_CAP_MAX_VCPUS and KVM_CAP_MAX_VCPU_ID.
8  */
9 
10 #define _GNU_SOURCE /* for program_invocation_short_name */
11 #include <fcntl.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15 
16 #include "test_util.h"
17 
18 #include "kvm_util.h"
19 #include "asm/kvm.h"
20 #include "linux/kvm.h"
21 
22 void test_vcpu_creation(int first_vcpu_id, int num_vcpus)
23 {
24 	struct kvm_vm *vm;
25 	int i;
26 
27 	pr_info("Testing creating %d vCPUs, with IDs %d...%d.\n",
28 		num_vcpus, first_vcpu_id, first_vcpu_id + num_vcpus - 1);
29 
30 	vm = vm_create(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES, O_RDWR);
31 
32 	for (i = first_vcpu_id; i < first_vcpu_id + num_vcpus; i++)
33 		/* This asserts that the vCPU was created. */
34 		vm_vcpu_add(vm, i);
35 
36 	kvm_vm_free(vm);
37 }
38 
39 int main(int argc, char *argv[])
40 {
41 	int kvm_max_vcpu_id = kvm_check_cap(KVM_CAP_MAX_VCPU_ID);
42 	int kvm_max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
43 
44 	pr_info("KVM_CAP_MAX_VCPU_ID: %d\n", kvm_max_vcpu_id);
45 	pr_info("KVM_CAP_MAX_VCPUS: %d\n", kvm_max_vcpus);
46 
47 	/*
48 	 * Upstream KVM prior to 4.8 does not support KVM_CAP_MAX_VCPU_ID.
49 	 * Userspace is supposed to use KVM_CAP_MAX_VCPUS as the maximum ID
50 	 * in this case.
51 	 */
52 	if (!kvm_max_vcpu_id)
53 		kvm_max_vcpu_id = kvm_max_vcpus;
54 
55 	TEST_ASSERT(kvm_max_vcpu_id >= kvm_max_vcpus,
56 		    "KVM_MAX_VCPU_ID (%d) must be at least as large as KVM_MAX_VCPUS (%d).",
57 		    kvm_max_vcpu_id, kvm_max_vcpus);
58 
59 	test_vcpu_creation(0, kvm_max_vcpus);
60 
61 	if (kvm_max_vcpu_id > kvm_max_vcpus)
62 		test_vcpu_creation(
63 			kvm_max_vcpu_id - kvm_max_vcpus, kvm_max_vcpus);
64 
65 	return 0;
66 }
67