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 
test_vcpu_creation(int first_vcpu_id,int num_vcpus)21 void 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 
main(int argc,char * argv[])38 int 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 }
93