1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Check for KVM_GET_REG_LIST regressions.
4  *
5  * Copyright (C) 2020, Red Hat, Inc.
6  *
7  * When attempting to migrate from a host with an older kernel to a host
8  * with a newer kernel we allow the newer kernel on the destination to
9  * list new registers with get-reg-list. We assume they'll be unused, at
10  * least until the guest reboots, and so they're relatively harmless.
11  * However, if the destination host with the newer kernel is missing
12  * registers which the source host with the older kernel has, then that's
13  * a regression in get-reg-list. This test checks for that regression by
14  * checking the current list against a blessed list. We should never have
15  * missing registers, but if new ones appear then they can probably be
16  * added to the blessed list. A completely new blessed list can be created
17  * by running the test with the --list command line argument.
18  *
19  * The blessed list should be created from the oldest possible kernel.
20  */
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <unistd.h>
25 #include <sys/types.h>
26 #include <sys/wait.h>
27 #include "kvm_util.h"
28 #include "test_util.h"
29 #include "processor.h"
30 
31 static struct kvm_reg_list *reg_list;
32 static __u64 *blessed_reg, blessed_n;
33 
34 extern struct vcpu_reg_list *vcpu_configs[];
35 extern int vcpu_configs_n;
36 
37 #define for_each_reg(i)								\
38 	for ((i) = 0; (i) < reg_list->n; ++(i))
39 
40 #define for_each_reg_filtered(i)						\
41 	for_each_reg(i)								\
42 		if (!filter_reg(reg_list->reg[i]))
43 
44 #define for_each_missing_reg(i)							\
45 	for ((i) = 0; (i) < blessed_n; ++(i))					\
46 		if (!find_reg(reg_list->reg, reg_list->n, blessed_reg[i]))	\
47 			if (check_supported_reg(vcpu, blessed_reg[i]))
48 
49 #define for_each_new_reg(i)							\
50 	for_each_reg_filtered(i)						\
51 		if (!find_reg(blessed_reg, blessed_n, reg_list->reg[i]))
52 
53 #define for_each_present_blessed_reg(i)						\
54 	for_each_reg(i)								\
55 		if (find_reg(blessed_reg, blessed_n, reg_list->reg[i]))
56 
config_name(struct vcpu_reg_list * c)57 static const char *config_name(struct vcpu_reg_list *c)
58 {
59 	struct vcpu_reg_sublist *s;
60 	int len = 0;
61 
62 	if (c->name)
63 		return c->name;
64 
65 	for_each_sublist(c, s)
66 		len += strlen(s->name) + 1;
67 
68 	c->name = malloc(len);
69 
70 	len = 0;
71 	for_each_sublist(c, s) {
72 		if (!strcmp(s->name, "base"))
73 			continue;
74 		strcat(c->name + len, s->name);
75 		len += strlen(s->name) + 1;
76 		c->name[len - 1] = '+';
77 	}
78 	c->name[len - 1] = '\0';
79 
80 	return c->name;
81 }
82 
check_supported_reg(struct kvm_vcpu * vcpu,__u64 reg)83 bool __weak check_supported_reg(struct kvm_vcpu *vcpu, __u64 reg)
84 {
85 	return true;
86 }
87 
filter_reg(__u64 reg)88 bool __weak filter_reg(__u64 reg)
89 {
90 	return false;
91 }
92 
find_reg(__u64 regs[],__u64 nr_regs,__u64 reg)93 static bool find_reg(__u64 regs[], __u64 nr_regs, __u64 reg)
94 {
95 	int i;
96 
97 	for (i = 0; i < nr_regs; ++i)
98 		if (reg == regs[i])
99 			return true;
100 	return false;
101 }
102 
print_reg(const char * prefix,__u64 id)103 void __weak print_reg(const char *prefix, __u64 id)
104 {
105 	printf("\t0x%llx,\n", id);
106 }
107 
check_reject_set(int err)108 bool __weak check_reject_set(int err)
109 {
110 	return true;
111 }
112 
finalize_vcpu(struct kvm_vcpu * vcpu,struct vcpu_reg_list * c)113 void __weak finalize_vcpu(struct kvm_vcpu *vcpu, struct vcpu_reg_list *c)
114 {
115 }
116 
117 #ifdef __aarch64__
prepare_vcpu_init(struct vcpu_reg_list * c,struct kvm_vcpu_init * init)118 static void prepare_vcpu_init(struct vcpu_reg_list *c, struct kvm_vcpu_init *init)
119 {
120 	struct vcpu_reg_sublist *s;
121 
122 	for_each_sublist(c, s)
123 		if (s->capability)
124 			init->features[s->feature / 32] |= 1 << (s->feature % 32);
125 }
126 
vcpu_config_get_vcpu(struct vcpu_reg_list * c,struct kvm_vm * vm)127 static struct kvm_vcpu *vcpu_config_get_vcpu(struct vcpu_reg_list *c, struct kvm_vm *vm)
128 {
129 	struct kvm_vcpu_init init = { .target = -1, };
130 	struct kvm_vcpu *vcpu;
131 
132 	prepare_vcpu_init(c, &init);
133 	vcpu = __vm_vcpu_add(vm, 0);
134 	aarch64_vcpu_setup(vcpu, &init);
135 
136 	return vcpu;
137 }
138 #else
vcpu_config_get_vcpu(struct vcpu_reg_list * c,struct kvm_vm * vm)139 static struct kvm_vcpu *vcpu_config_get_vcpu(struct vcpu_reg_list *c, struct kvm_vm *vm)
140 {
141 	return __vm_vcpu_add(vm, 0);
142 }
143 #endif
144 
check_supported(struct vcpu_reg_list * c)145 static void check_supported(struct vcpu_reg_list *c)
146 {
147 	struct vcpu_reg_sublist *s;
148 
149 	for_each_sublist(c, s) {
150 		if (!s->capability)
151 			continue;
152 
153 		__TEST_REQUIRE(kvm_has_cap(s->capability),
154 			       "%s: %s not available, skipping tests\n",
155 			       config_name(c), s->name);
156 	}
157 }
158 
159 static bool print_list;
160 static bool print_filtered;
161 
run_test(struct vcpu_reg_list * c)162 static void run_test(struct vcpu_reg_list *c)
163 {
164 	int new_regs = 0, missing_regs = 0, i, n;
165 	int failed_get = 0, failed_set = 0, failed_reject = 0;
166 	int skipped_set = 0;
167 	struct kvm_vcpu *vcpu;
168 	struct kvm_vm *vm;
169 	struct vcpu_reg_sublist *s;
170 
171 	check_supported(c);
172 
173 	vm = vm_create_barebones();
174 	vcpu = vcpu_config_get_vcpu(c, vm);
175 	finalize_vcpu(vcpu, c);
176 
177 	reg_list = vcpu_get_reg_list(vcpu);
178 
179 	if (print_list || print_filtered) {
180 		putchar('\n');
181 		for_each_reg(i) {
182 			__u64 id = reg_list->reg[i];
183 			if ((print_list && !filter_reg(id)) ||
184 			    (print_filtered && filter_reg(id)))
185 				print_reg(config_name(c), id);
186 		}
187 		putchar('\n');
188 		return;
189 	}
190 
191 	for_each_sublist(c, s)
192 		blessed_n += s->regs_n;
193 	blessed_reg = calloc(blessed_n, sizeof(__u64));
194 
195 	n = 0;
196 	for_each_sublist(c, s) {
197 		for (i = 0; i < s->regs_n; ++i)
198 			blessed_reg[n++] = s->regs[i];
199 	}
200 
201 	/*
202 	 * We only test that we can get the register and then write back the
203 	 * same value. Some registers may allow other values to be written
204 	 * back, but others only allow some bits to be changed, and at least
205 	 * for ID registers set will fail if the value does not exactly match
206 	 * what was returned by get. If registers that allow other values to
207 	 * be written need to have the other values tested, then we should
208 	 * create a new set of tests for those in a new independent test
209 	 * executable.
210 	 *
211 	 * Only do the get/set tests on present, blessed list registers,
212 	 * since we don't know the capabilities of any new registers.
213 	 */
214 	for_each_present_blessed_reg(i) {
215 		uint8_t addr[2048 / 8];
216 		struct kvm_one_reg reg = {
217 			.id = reg_list->reg[i],
218 			.addr = (__u64)&addr,
219 		};
220 		bool reject_reg = false, skip_reg = false;
221 		int ret;
222 
223 		ret = __vcpu_get_reg(vcpu, reg_list->reg[i], &addr);
224 		if (ret) {
225 			printf("%s: Failed to get ", config_name(c));
226 			print_reg(config_name(c), reg.id);
227 			putchar('\n');
228 			++failed_get;
229 		}
230 
231 		for_each_sublist(c, s) {
232 			/* rejects_set registers are rejected for set operation */
233 			if (s->rejects_set && find_reg(s->rejects_set, s->rejects_set_n, reg.id)) {
234 				reject_reg = true;
235 				ret = __vcpu_ioctl(vcpu, KVM_SET_ONE_REG, &reg);
236 				if (ret != -1 || !check_reject_set(errno)) {
237 					printf("%s: Failed to reject (ret=%d, errno=%d) ", config_name(c), ret, errno);
238 					print_reg(config_name(c), reg.id);
239 					putchar('\n');
240 					++failed_reject;
241 				}
242 				break;
243 			}
244 
245 			/* skips_set registers are skipped for set operation */
246 			if (s->skips_set && find_reg(s->skips_set, s->skips_set_n, reg.id)) {
247 				skip_reg = true;
248 				++skipped_set;
249 				break;
250 			}
251 		}
252 
253 		if (!reject_reg && !skip_reg) {
254 			ret = __vcpu_ioctl(vcpu, KVM_SET_ONE_REG, &reg);
255 			if (ret) {
256 				printf("%s: Failed to set ", config_name(c));
257 				print_reg(config_name(c), reg.id);
258 				putchar('\n');
259 				++failed_set;
260 			}
261 		}
262 	}
263 
264 	for_each_new_reg(i)
265 		++new_regs;
266 
267 	for_each_missing_reg(i)
268 		++missing_regs;
269 
270 	if (new_regs || missing_regs) {
271 		n = 0;
272 		for_each_reg_filtered(i)
273 			++n;
274 
275 		printf("%s: Number blessed registers: %5lld\n", config_name(c), blessed_n);
276 		printf("%s: Number registers:         %5lld (includes %lld filtered registers)\n",
277 		       config_name(c), reg_list->n, reg_list->n - n);
278 	}
279 
280 	if (new_regs) {
281 		printf("\n%s: There are %d new registers.\n"
282 		       "Consider adding them to the blessed reg "
283 		       "list with the following lines:\n\n", config_name(c), new_regs);
284 		for_each_new_reg(i)
285 			print_reg(config_name(c), reg_list->reg[i]);
286 		putchar('\n');
287 	}
288 
289 	if (missing_regs) {
290 		printf("\n%s: There are %d missing registers.\n"
291 		       "The following lines are missing registers:\n\n", config_name(c), missing_regs);
292 		for_each_missing_reg(i)
293 			print_reg(config_name(c), blessed_reg[i]);
294 		putchar('\n');
295 	}
296 
297 	TEST_ASSERT(!missing_regs && !failed_get && !failed_set && !failed_reject,
298 		    "%s: There are %d missing registers; %d registers failed get; "
299 		    "%d registers failed set; %d registers failed reject; %d registers skipped set",
300 		    config_name(c), missing_regs, failed_get, failed_set, failed_reject, skipped_set);
301 
302 	pr_info("%s: PASS\n", config_name(c));
303 	blessed_n = 0;
304 	free(blessed_reg);
305 	free(reg_list);
306 	kvm_vm_free(vm);
307 }
308 
help(void)309 static void help(void)
310 {
311 	struct vcpu_reg_list *c;
312 	int i;
313 
314 	printf(
315 	"\n"
316 	"usage: get-reg-list [--config=<selection>] [--list] [--list-filtered]\n\n"
317 	" --config=<selection>        Used to select a specific vcpu configuration for the test/listing\n"
318 	"                             '<selection>' may be\n");
319 
320 	for (i = 0; i < vcpu_configs_n; ++i) {
321 		c = vcpu_configs[i];
322 		printf(
323 	"                               '%s'\n", config_name(c));
324 	}
325 
326 	printf(
327 	"\n"
328 	" --list                      Print the register list rather than test it (requires --config)\n"
329 	" --list-filtered             Print registers that would normally be filtered out (requires --config)\n"
330 	"\n"
331 	);
332 }
333 
parse_config(const char * config)334 static struct vcpu_reg_list *parse_config(const char *config)
335 {
336 	struct vcpu_reg_list *c = NULL;
337 	int i;
338 
339 	if (config[8] != '=')
340 		help(), exit(1);
341 
342 	for (i = 0; i < vcpu_configs_n; ++i) {
343 		c = vcpu_configs[i];
344 		if (strcmp(config_name(c), &config[9]) == 0)
345 			break;
346 	}
347 
348 	if (i == vcpu_configs_n)
349 		help(), exit(1);
350 
351 	return c;
352 }
353 
main(int ac,char ** av)354 int main(int ac, char **av)
355 {
356 	struct vcpu_reg_list *c, *sel = NULL;
357 	int i, ret = 0;
358 	pid_t pid;
359 
360 	for (i = 1; i < ac; ++i) {
361 		if (strncmp(av[i], "--config", 8) == 0)
362 			sel = parse_config(av[i]);
363 		else if (strcmp(av[i], "--list") == 0)
364 			print_list = true;
365 		else if (strcmp(av[i], "--list-filtered") == 0)
366 			print_filtered = true;
367 		else if (strcmp(av[i], "--help") == 0 || strcmp(av[1], "-h") == 0)
368 			help(), exit(0);
369 		else
370 			help(), exit(1);
371 	}
372 
373 	if (print_list || print_filtered) {
374 		/*
375 		 * We only want to print the register list of a single config.
376 		 */
377 		if (!sel)
378 			help(), exit(1);
379 	}
380 
381 	for (i = 0; i < vcpu_configs_n; ++i) {
382 		c = vcpu_configs[i];
383 		if (sel && c != sel)
384 			continue;
385 
386 		pid = fork();
387 
388 		if (!pid) {
389 			run_test(c);
390 			exit(0);
391 		} else {
392 			int wstatus;
393 			pid_t wpid = wait(&wstatus);
394 			TEST_ASSERT(wpid == pid && WIFEXITED(wstatus), "wait: Unexpected return");
395 			if (WEXITSTATUS(wstatus) && WEXITSTATUS(wstatus) != KSFT_SKIP)
396 				ret = KSFT_FAIL;
397 		}
398 	}
399 
400 	return ret;
401 }
402