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#include <sys/resource.h>
16
17#include "test_util.h"
18
19#include "kvm_util.h"
20#include "asm/kvm.h"
21#include "linux/kvm.h"
22
23void test_vcpu_creation(int first_vcpu_id, int num_vcpus)
24{
25	struct kvm_vm *vm;
26	int i;
27
28	pr_info("Testing creating %d vCPUs, with IDs %d...%d.\n",
29		num_vcpus, first_vcpu_id, first_vcpu_id + num_vcpus - 1);
30
31	vm = vm_create_barebones();
32
33	for (i = first_vcpu_id; i < first_vcpu_id + num_vcpus; i++)
34		/* This asserts that the vCPU was created. */
35		__vm_vcpu_add(vm, i);
36
37	kvm_vm_free(vm);
38}
39
40int main(int argc, char *argv[])
41{
42	int kvm_max_vcpu_id = kvm_check_cap(KVM_CAP_MAX_VCPU_ID);
43	int kvm_max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
44	/*
45	 * Number of file descriptors reqired, KVM_CAP_MAX_VCPUS for vCPU fds +
46	 * an arbitrary number for everything else.
47	 */
48	int nr_fds_wanted = kvm_max_vcpus + 100;
49	struct rlimit rl;
50
51	pr_info("KVM_CAP_MAX_VCPU_ID: %d\n", kvm_max_vcpu_id);
52	pr_info("KVM_CAP_MAX_VCPUS: %d\n", kvm_max_vcpus);
53
54	/*
55	 * Check that we're allowed to open nr_fds_wanted file descriptors and
56	 * try raising the limits if needed.
57	 */
58	TEST_ASSERT(!getrlimit(RLIMIT_NOFILE, &rl), "getrlimit() failed!");
59
60	if (rl.rlim_cur < nr_fds_wanted) {
61		rl.rlim_cur = nr_fds_wanted;
62		if (rl.rlim_max < nr_fds_wanted) {
63			int old_rlim_max = rl.rlim_max;
64			rl.rlim_max = nr_fds_wanted;
65
66			int r = setrlimit(RLIMIT_NOFILE, &rl);
67			__TEST_REQUIRE(r >= 0,
68				       "RLIMIT_NOFILE hard limit is too low (%d, wanted %d)",
69				       old_rlim_max, nr_fds_wanted);
70		} else {
71			TEST_ASSERT(!setrlimit(RLIMIT_NOFILE, &rl), "setrlimit() failed!");
72		}
73	}
74
75	/*
76	 * Upstream KVM prior to 4.8 does not support KVM_CAP_MAX_VCPU_ID.
77	 * Userspace is supposed to use KVM_CAP_MAX_VCPUS as the maximum ID
78	 * in this case.
79	 */
80	if (!kvm_max_vcpu_id)
81		kvm_max_vcpu_id = kvm_max_vcpus;
82
83	TEST_ASSERT(kvm_max_vcpu_id >= kvm_max_vcpus,
84		    "KVM_MAX_VCPU_IDS (%d) must be at least as large as KVM_MAX_VCPUS (%d).",
85		    kvm_max_vcpu_id, kvm_max_vcpus);
86
87	test_vcpu_creation(0, kvm_max_vcpus);
88
89	if (kvm_max_vcpu_id > kvm_max_vcpus)
90		test_vcpu_creation(
91			kvm_max_vcpu_id - kvm_max_vcpus, kvm_max_vcpus);
92
93	return 0;
94}
95