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#include <fcntl.h>
10#include <stdio.h>
11#include <stdlib.h>
12#include <string.h>
13#include <sys/resource.h>
14
15#include "test_util.h"
16
17#include "kvm_util.h"
18#include "asm/kvm.h"
19#include "linux/kvm.h"
20
21void test_vcpu_creation(int first_vcpu_id, int num_vcpus)
22{
23	struct kvm_vm *vm;
24	int i;
25
26	pr_info("Testing creating %d vCPUs, with IDs %d...%d.\n",
27		num_vcpus, first_vcpu_id, first_vcpu_id + num_vcpus - 1);
28
29	vm = vm_create_barebones();
30
31	for (i = first_vcpu_id; i < first_vcpu_id + num_vcpus; i++)
32		/* This asserts that the vCPU was created. */
33		__vm_vcpu_add(vm, i);
34
35	kvm_vm_free(vm);
36}
37
38int main(int argc, char *argv[])
39{
40	int kvm_max_vcpu_id = kvm_check_cap(KVM_CAP_MAX_VCPU_ID);
41	int kvm_max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
42	/*
43	 * Number of file descriptors reqired, KVM_CAP_MAX_VCPUS for vCPU fds +
44	 * an arbitrary number for everything else.
45	 */
46	int nr_fds_wanted = kvm_max_vcpus + 100;
47	struct rlimit rl;
48
49	pr_info("KVM_CAP_MAX_VCPU_ID: %d\n", kvm_max_vcpu_id);
50	pr_info("KVM_CAP_MAX_VCPUS: %d\n", kvm_max_vcpus);
51
52	/*
53	 * Check that we're allowed to open nr_fds_wanted file descriptors and
54	 * try raising the limits if needed.
55	 */
56	TEST_ASSERT(!getrlimit(RLIMIT_NOFILE, &rl), "getrlimit() failed!");
57
58	if (rl.rlim_cur < nr_fds_wanted) {
59		rl.rlim_cur = nr_fds_wanted;
60		if (rl.rlim_max < nr_fds_wanted) {
61			int old_rlim_max = rl.rlim_max;
62			rl.rlim_max = nr_fds_wanted;
63
64			int r = setrlimit(RLIMIT_NOFILE, &rl);
65			__TEST_REQUIRE(r >= 0,
66				       "RLIMIT_NOFILE hard limit is too low (%d, wanted %d)",
67				       old_rlim_max, nr_fds_wanted);
68		} else {
69			TEST_ASSERT(!setrlimit(RLIMIT_NOFILE, &rl), "setrlimit() failed!");
70		}
71	}
72
73	/*
74	 * Upstream KVM prior to 4.8 does not support KVM_CAP_MAX_VCPU_ID.
75	 * Userspace is supposed to use KVM_CAP_MAX_VCPUS as the maximum ID
76	 * in this case.
77	 */
78	if (!kvm_max_vcpu_id)
79		kvm_max_vcpu_id = kvm_max_vcpus;
80
81	TEST_ASSERT(kvm_max_vcpu_id >= kvm_max_vcpus,
82		    "KVM_MAX_VCPU_IDS (%d) must be at least as large as KVM_MAX_VCPUS (%d).",
83		    kvm_max_vcpu_id, kvm_max_vcpus);
84
85	test_vcpu_creation(0, kvm_max_vcpus);
86
87	if (kvm_max_vcpu_id > kvm_max_vcpus)
88		test_vcpu_creation(
89			kvm_max_vcpu_id - kvm_max_vcpus, kvm_max_vcpus);
90
91	return 0;
92}