1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * kvm_binary_stats_test
4  *
5  * Copyright (C) 2021, Google LLC.
6  *
7  * Test the fd-based interface for KVM statistics.
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 <errno.h>
16 
17 #include "test_util.h"
18 
19 #include "kvm_util.h"
20 #include "asm/kvm.h"
21 #include "linux/kvm.h"
22 #include "kselftest.h"
23 
stats_test(int stats_fd)24 static void stats_test(int stats_fd)
25 {
26 	ssize_t ret;
27 	int i;
28 	size_t size_desc;
29 	size_t size_data = 0;
30 	struct kvm_stats_header header;
31 	char *id;
32 	struct kvm_stats_desc *stats_desc;
33 	u64 *stats_data;
34 	struct kvm_stats_desc *pdesc;
35 	u32 type, unit, base;
36 
37 	/* Read kvm stats header */
38 	read_stats_header(stats_fd, &header);
39 
40 	size_desc = get_stats_descriptor_size(&header);
41 
42 	/* Read kvm stats id string */
43 	id = malloc(header.name_size);
44 	TEST_ASSERT(id, "Allocate memory for id string");
45 
46 	ret = pread(stats_fd, id, header.name_size, sizeof(header));
47 	TEST_ASSERT(ret == header.name_size,
48 		    "Expected header size '%u', read '%lu' bytes",
49 		    header.name_size, ret);
50 
51 	/* Check id string, that should start with "kvm" */
52 	TEST_ASSERT(!strncmp(id, "kvm", 3) && strlen(id) < header.name_size,
53 		    "Invalid KVM stats type, id: %s", id);
54 
55 	/* Sanity check for other fields in header */
56 	if (header.num_desc == 0) {
57 		ksft_print_msg("No KVM stats defined!\n");
58 		return;
59 	}
60 	/*
61 	 * The descriptor and data offsets must be valid, they must not overlap
62 	 * the header, and the descriptor and data blocks must not overlap each
63 	 * other.  Note, the data block is rechecked after its size is known.
64 	 */
65 	TEST_ASSERT(header.desc_offset && header.desc_offset >= sizeof(header) &&
66 		    header.data_offset && header.data_offset >= sizeof(header),
67 		    "Invalid offset fields in header");
68 
69 	TEST_ASSERT(header.desc_offset > header.data_offset ||
70 		    (header.desc_offset + size_desc * header.num_desc <= header.data_offset),
71 		    "Descriptor block is overlapped with data block");
72 
73 	/* Read kvm stats descriptors */
74 	stats_desc = read_stats_descriptors(stats_fd, &header);
75 
76 	/* Sanity check for fields in descriptors */
77 	for (i = 0; i < header.num_desc; ++i) {
78 		pdesc = get_stats_descriptor(stats_desc, i, &header);
79 		type = pdesc->flags & KVM_STATS_TYPE_MASK;
80 		unit = pdesc->flags & KVM_STATS_UNIT_MASK;
81 		base = pdesc->flags & KVM_STATS_BASE_MASK;
82 
83 		/* Check name string */
84 		TEST_ASSERT(strlen(pdesc->name) < header.name_size,
85 			    "KVM stats name (index: %d) too long", i);
86 
87 		/* Check type,unit,base boundaries */
88 		TEST_ASSERT(type <= KVM_STATS_TYPE_MAX,
89 			    "Unknown KVM stats (%s) type: %u", pdesc->name, type);
90 		TEST_ASSERT(unit <= KVM_STATS_UNIT_MAX,
91 			    "Unknown KVM stats (%s) unit: %u", pdesc->name, unit);
92 		TEST_ASSERT(base <= KVM_STATS_BASE_MAX,
93 			    "Unknown KVM stats (%s) base: %u", pdesc->name, base);
94 
95 		/*
96 		 * Check exponent for stats unit
97 		 * Exponent for counter should be greater than or equal to 0
98 		 * Exponent for unit bytes should be greater than or equal to 0
99 		 * Exponent for unit seconds should be less than or equal to 0
100 		 * Exponent for unit clock cycles should be greater than or
101 		 * equal to 0
102 		 * Exponent for unit boolean should be 0
103 		 */
104 		switch (pdesc->flags & KVM_STATS_UNIT_MASK) {
105 		case KVM_STATS_UNIT_NONE:
106 		case KVM_STATS_UNIT_BYTES:
107 		case KVM_STATS_UNIT_CYCLES:
108 			TEST_ASSERT(pdesc->exponent >= 0,
109 				    "Unsupported KVM stats (%s) exponent: %i",
110 				    pdesc->name, pdesc->exponent);
111 			break;
112 		case KVM_STATS_UNIT_SECONDS:
113 			TEST_ASSERT(pdesc->exponent <= 0,
114 				    "Unsupported KVM stats (%s) exponent: %i",
115 				    pdesc->name, pdesc->exponent);
116 			break;
117 		case KVM_STATS_UNIT_BOOLEAN:
118 			TEST_ASSERT(pdesc->exponent == 0,
119 				    "Unsupported KVM stats (%s) exponent: %d",
120 				    pdesc->name, pdesc->exponent);
121 			break;
122 		}
123 
124 		/* Check size field, which should not be zero */
125 		TEST_ASSERT(pdesc->size,
126 			    "KVM descriptor(%s) with size of 0", pdesc->name);
127 		/* Check bucket_size field */
128 		switch (pdesc->flags & KVM_STATS_TYPE_MASK) {
129 		case KVM_STATS_TYPE_LINEAR_HIST:
130 			TEST_ASSERT(pdesc->bucket_size,
131 				    "Bucket size of Linear Histogram stats (%s) is zero",
132 				    pdesc->name);
133 			break;
134 		default:
135 			TEST_ASSERT(!pdesc->bucket_size,
136 				    "Bucket size of stats (%s) is not zero",
137 				    pdesc->name);
138 		}
139 		size_data = max(size_data, pdesc->offset + pdesc->size * sizeof(*stats_data));
140 	}
141 
142 	/*
143 	 * Now that the size of the data block is known, verify the data block
144 	 * doesn't overlap the descriptor block.
145 	 */
146 	TEST_ASSERT(header.data_offset >= header.desc_offset ||
147 		    header.data_offset + size_data <= header.desc_offset,
148 		    "Data block is overlapped with Descriptor block");
149 
150 	/* Check validity of all stats data size */
151 	TEST_ASSERT(size_data >= header.num_desc * sizeof(*stats_data),
152 		    "Data size is not correct");
153 
154 	/* Allocate memory for stats data */
155 	stats_data = malloc(size_data);
156 	TEST_ASSERT(stats_data, "Allocate memory for stats data");
157 	/* Read kvm stats data as a bulk */
158 	ret = pread(stats_fd, stats_data, size_data, header.data_offset);
159 	TEST_ASSERT(ret == size_data, "Read KVM stats data");
160 	/* Read kvm stats data one by one */
161 	for (i = 0; i < header.num_desc; ++i) {
162 		pdesc = get_stats_descriptor(stats_desc, i, &header);
163 		read_stat_data(stats_fd, &header, pdesc, stats_data,
164 			       pdesc->size);
165 	}
166 
167 	free(stats_data);
168 	free(stats_desc);
169 	free(id);
170 
171 	close(stats_fd);
172 	TEST_ASSERT(fcntl(stats_fd, F_GETFD) == -1, "Stats fd not freed");
173 }
174 
175 #define DEFAULT_NUM_VM		4
176 #define DEFAULT_NUM_VCPU	4
177 
178 /*
179  * Usage: kvm_bin_form_stats [#vm] [#vcpu]
180  * The first parameter #vm set the number of VMs being created.
181  * The second parameter #vcpu set the number of VCPUs being created.
182  * By default, DEFAULT_NUM_VM VM and DEFAULT_NUM_VCPU VCPU for the VM would be
183  * created for testing.
184  */
185 
main(int argc,char * argv[])186 int main(int argc, char *argv[])
187 {
188 	int vm_stats_fds, *vcpu_stats_fds;
189 	int i, j;
190 	struct kvm_vcpu **vcpus;
191 	struct kvm_vm **vms;
192 	int max_vm = DEFAULT_NUM_VM;
193 	int max_vcpu = DEFAULT_NUM_VCPU;
194 
195 	/* Get the number of VMs and VCPUs that would be created for testing. */
196 	if (argc > 1) {
197 		max_vm = strtol(argv[1], NULL, 0);
198 		if (max_vm <= 0)
199 			max_vm = DEFAULT_NUM_VM;
200 	}
201 	if (argc > 2) {
202 		max_vcpu = strtol(argv[2], NULL, 0);
203 		if (max_vcpu <= 0)
204 			max_vcpu = DEFAULT_NUM_VCPU;
205 	}
206 
207 	ksft_print_header();
208 
209 	/* Check the extension for binary stats */
210 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_BINARY_STATS_FD));
211 
212 	ksft_set_plan(max_vm);
213 
214 	/* Create VMs and VCPUs */
215 	vms = malloc(sizeof(vms[0]) * max_vm);
216 	TEST_ASSERT(vms, "Allocate memory for storing VM pointers");
217 
218 	vcpus = malloc(sizeof(struct kvm_vcpu *) * max_vm * max_vcpu);
219 	TEST_ASSERT(vcpus, "Allocate memory for storing vCPU pointers");
220 
221 	/*
222 	 * Not per-VM as the array is populated, used, and invalidated within a
223 	 * single for-loop iteration.
224 	 */
225 	vcpu_stats_fds = calloc(max_vm, sizeof(*vcpu_stats_fds));
226 	TEST_ASSERT(vcpu_stats_fds, "Allocate memory for VM stats fds");
227 
228 	for (i = 0; i < max_vm; ++i) {
229 		vms[i] = vm_create_barebones();
230 		for (j = 0; j < max_vcpu; ++j)
231 			vcpus[i * max_vcpu + j] = __vm_vcpu_add(vms[i], j);
232 	}
233 
234 	/*
235 	 * Check stats read for every VM and vCPU, with a variety of flavors.
236 	 * Note, stats_test() closes the passed in stats fd.
237 	 */
238 	for (i = 0; i < max_vm; ++i) {
239 		/*
240 		 * Verify that creating multiple userspace references to a
241 		 * single stats file works and doesn't cause explosions.
242 		 */
243 		vm_stats_fds = vm_get_stats_fd(vms[i]);
244 		stats_test(dup(vm_stats_fds));
245 
246 		/* Verify userspace can instantiate multiple stats files. */
247 		stats_test(vm_get_stats_fd(vms[i]));
248 
249 		for (j = 0; j < max_vcpu; ++j) {
250 			vcpu_stats_fds[j] = vcpu_get_stats_fd(vcpus[i * max_vcpu + j]);
251 			stats_test(dup(vcpu_stats_fds[j]));
252 			stats_test(vcpu_get_stats_fd(vcpus[i * max_vcpu + j]));
253 		}
254 
255 		/*
256 		 * Close the VM fd and redo the stats tests.  KVM should gift a
257 		 * reference (to the VM) to each stats fd, i.e. stats should
258 		 * still be accessible even after userspace has put its last
259 		 * _direct_ reference to the VM.
260 		 */
261 		kvm_vm_free(vms[i]);
262 
263 		stats_test(vm_stats_fds);
264 		for (j = 0; j < max_vcpu; ++j)
265 			stats_test(vcpu_stats_fds[j]);
266 
267 		ksft_test_result_pass("vm%i\n", i);
268 	}
269 
270 	free(vms);
271 	free(vcpus);
272 	free(vcpu_stats_fds);
273 
274 	ksft_finished();	/* Print results and exit() accordingly */
275 }
276