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 
23 void 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(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES, O_RDWR);
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 
40 int 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 			if (r < 0) {
68 				printf("RLIMIT_NOFILE hard limit is too low (%d, wanted %d)\n",
69 				       old_rlim_max, nr_fds_wanted);
70 				exit(KSFT_SKIP);
71 			}
72 		} else {
73 			TEST_ASSERT(!setrlimit(RLIMIT_NOFILE, &rl), "setrlimit() failed!");
74 		}
75 	}
76 
77 	/*
78 	 * Upstream KVM prior to 4.8 does not support KVM_CAP_MAX_VCPU_ID.
79 	 * Userspace is supposed to use KVM_CAP_MAX_VCPUS as the maximum ID
80 	 * in this case.
81 	 */
82 	if (!kvm_max_vcpu_id)
83 		kvm_max_vcpu_id = kvm_max_vcpus;
84 
85 	TEST_ASSERT(kvm_max_vcpu_id >= kvm_max_vcpus,
86 		    "KVM_MAX_VCPU_IDS (%d) must be at least as large as KVM_MAX_VCPUS (%d).",
87 		    kvm_max_vcpu_id, kvm_max_vcpus);
88 
89 	test_vcpu_creation(0, kvm_max_vcpus);
90 
91 	if (kvm_max_vcpu_id > kvm_max_vcpus)
92 		test_vcpu_creation(
93 			kvm_max_vcpu_id - kvm_max_vcpus, kvm_max_vcpus);
94 
95 	return 0;
96 }
97