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 	printf("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 = 0; i < num_vcpus; i++) {
33 		int vcpu_id = first_vcpu_id + i;
34 
35 		/* This asserts that the vCPU was created. */
36 		vm_vcpu_add(vm, vcpu_id);
37 	}
38 
39 	kvm_vm_free(vm);
40 }
41 
42 int main(int argc, char *argv[])
43 {
44 	int kvm_max_vcpu_id = kvm_check_cap(KVM_CAP_MAX_VCPU_ID);
45 	int kvm_max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
46 
47 	printf("KVM_CAP_MAX_VCPU_ID: %d\n", kvm_max_vcpu_id);
48 	printf("KVM_CAP_MAX_VCPUS: %d\n", kvm_max_vcpus);
49 
50 	/*
51 	 * Upstream KVM prior to 4.8 does not support KVM_CAP_MAX_VCPU_ID.
52 	 * Userspace is supposed to use KVM_CAP_MAX_VCPUS as the maximum ID
53 	 * in this case.
54 	 */
55 	if (!kvm_max_vcpu_id)
56 		kvm_max_vcpu_id = kvm_max_vcpus;
57 
58 	TEST_ASSERT(kvm_max_vcpu_id >= kvm_max_vcpus,
59 		    "KVM_MAX_VCPU_ID (%d) must be at least as large as KVM_MAX_VCPUS (%d).",
60 		    kvm_max_vcpu_id, kvm_max_vcpus);
61 
62 	test_vcpu_creation(0, kvm_max_vcpus);
63 
64 	if (kvm_max_vcpu_id > kvm_max_vcpus)
65 		test_vcpu_creation(
66 			kvm_max_vcpu_id - kvm_max_vcpus, kvm_max_vcpus);
67 
68 	return 0;
69 }
70