1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Storage Key migration tests
4 *
5 * There are two variants of this test:
6 * - sequential: set storage keys on some pages, migrates the VM and then
7 * verifies that the storage keys are still as we expect.
8 * - parallel: start migration and set and check storage keys on some
9 * pages while migration is in process.
10 *
11 * Copyright IBM Corp. 2022
12 *
13 * Authors:
14 * Nico Boehr <nrb@linux.ibm.com>
15 */
16
17 #include <libcflat.h>
18 #include <migrate.h>
19 #include <asm/facility.h>
20 #include <asm/page.h>
21 #include <asm/mem.h>
22 #include <asm/barrier.h>
23 #include <hardware.h>
24 #include <smp.h>
25
26 struct verify_result {
27 bool verify_failed;
28 union skey expected_key;
29 union skey actual_key;
30 unsigned long page_mismatch_idx;
31 unsigned long page_mismatch_addr;
32 };
33
34 #define NUM_PAGES 128
35 static uint8_t pagebuf[NUM_PAGES * PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
36
37 static struct verify_result result;
38
39 static unsigned int thread_iters;
40 static bool thread_should_exit;
41 static bool thread_exited;
42
43 static enum {
44 TEST_INVALID,
45 TEST_SEQUENTIAL,
46 TEST_PARALLEL
47 } arg_test_to_run;
48
49 /*
50 * Set storage key test pattern on pagebuf with a seed for the storage keys.
51 *
52 * Each page's storage key is generated by taking the page's index in pagebuf,
53 * XOR-ing that with the given seed and then multipling the result with two.
54 *
55 * Only the lower seven bits of the seed are considered.
56 */
set_test_pattern(unsigned char seed)57 static void set_test_pattern(unsigned char seed)
58 {
59 unsigned char key_to_set;
60 unsigned long i;
61
62 for (i = 0; i < NUM_PAGES; i++) {
63 /*
64 * Storage keys are 7 bit, lowest bit is always returned as zero
65 * by iske.
66 * This loop will set all 7 bits which means we set fetch
67 * protection as well as reference and change indication for
68 * some keys.
69 */
70 key_to_set = (i ^ seed) * 2;
71 set_storage_key(pagebuf + i * PAGE_SIZE, key_to_set, 1);
72 }
73 }
74
75 /*
76 * Verify storage keys on pagebuf.
77 * Storage keys must have been set by set_test_pattern on pagebuf before.
78 * set_test_pattern must have been called with the same seed value.
79 *
80 * If storage keys match the expected result, will return a verify_result
81 * with verify_failed false. All other fields are then invalid.
82 * If there is a mismatch, returned struct will have verify_failed true and will
83 * be filled with the details on the first mismatch encountered.
84 */
verify_test_pattern(unsigned char seed)85 static struct verify_result verify_test_pattern(unsigned char seed)
86 {
87 union skey expected_key, actual_key;
88 struct verify_result result = {
89 .verify_failed = true
90 };
91 uint8_t *cur_page;
92 unsigned long i;
93
94 for (i = 0; i < NUM_PAGES; i++) {
95 cur_page = pagebuf + i * PAGE_SIZE;
96 actual_key.val = get_storage_key(cur_page);
97 expected_key.val = (i ^ seed) * 2;
98
99 /*
100 * The PoP neither gives a guarantee that the reference bit is
101 * accurate nor that it won't be cleared by hardware. Hence we
102 * don't rely on it and just clear the bits to avoid compare
103 * errors.
104 */
105 actual_key.str.rf = 0;
106 expected_key.str.rf = 0;
107
108 if (actual_key.val != expected_key.val) {
109 result.expected_key.val = expected_key.val;
110 result.actual_key.val = actual_key.val;
111 result.page_mismatch_idx = i;
112 result.page_mismatch_addr = (unsigned long)cur_page;
113 return result;
114 }
115 }
116
117 result.verify_failed = false;
118 return result;
119 }
120
report_verify_result(const struct verify_result * result)121 static void report_verify_result(const struct verify_result * result)
122 {
123 if (result->verify_failed)
124 report_fail("page skey mismatch: first page idx = %lu, addr = 0x%lx, "
125 "expected_key = 0x%02x, actual_key = 0x%02x",
126 result->page_mismatch_idx, result->page_mismatch_addr,
127 result->expected_key.val, result->actual_key.val);
128 else
129 report_pass("skeys match");
130 }
131
test_skey_migration_sequential(void)132 static void test_skey_migration_sequential(void)
133 {
134 report_prefix_push("sequential");
135
136 set_test_pattern(0);
137
138 migrate_once();
139
140 result = verify_test_pattern(0);
141 report_verify_result(&result);
142
143 report_prefix_pop();
144 }
145
set_skeys_thread(void)146 static void set_skeys_thread(void)
147 {
148 while (!READ_ONCE(thread_should_exit)) {
149 set_test_pattern(thread_iters);
150
151 result = verify_test_pattern(thread_iters);
152
153 /*
154 * Always increment even if the verify fails. This ensures primary CPU knows where
155 * we left off and can do an additional verify round after migration finished.
156 */
157 thread_iters++;
158
159 if (result.verify_failed)
160 break;
161 }
162
163 WRITE_ONCE(thread_exited, 1);
164 }
165
test_skey_migration_parallel(void)166 static void test_skey_migration_parallel(void)
167 {
168 report_prefix_push("parallel");
169
170 if (smp_query_num_cpus() == 1) {
171 report_skip("need at least 2 cpus for this test");
172 migrate_skip();
173 goto error;
174 }
175
176 smp_cpu_setup(1, PSW_WITH_CUR_MASK(set_skeys_thread));
177
178 migrate_once();
179
180 WRITE_ONCE(thread_should_exit, 1);
181
182 while (!READ_ONCE(thread_exited))
183 ;
184
185 /* Ensure we read result and thread_iters below from memory after thread exited */
186 mb();
187 report_info("thread completed %u iterations", thread_iters);
188
189 report_prefix_push("during migration");
190 report_verify_result(&result);
191 report_prefix_pop();
192
193 /*
194 * Verification of skeys occurs on the thread. We don't know if we
195 * were still migrating during the verification.
196 * To be sure, make another verification round after the migration
197 * finished to catch skeys which might not have been migrated
198 * correctly.
199 */
200 report_prefix_push("after migration");
201 assert(thread_iters > 0);
202 result = verify_test_pattern(thread_iters - 1);
203 report_verify_result(&result);
204 report_prefix_pop();
205
206 error:
207 report_prefix_pop();
208 }
209
print_usage(void)210 static void print_usage(void)
211 {
212 report_info("Usage: migration-skey [--parallel|--sequential]");
213 }
214
parse_args(int argc,char ** argv)215 static void parse_args(int argc, char **argv)
216 {
217 if (argc < 2) {
218 /* default to sequential since it only needs one cpu */
219 arg_test_to_run = TEST_SEQUENTIAL;
220 return;
221 }
222
223 if (!strcmp("--parallel", argv[1]))
224 arg_test_to_run = TEST_PARALLEL;
225 else if (!strcmp("--sequential", argv[1]))
226 arg_test_to_run = TEST_SEQUENTIAL;
227 else
228 arg_test_to_run = TEST_INVALID;
229 }
230
main(int argc,char ** argv)231 int main(int argc, char **argv)
232 {
233 report_prefix_push("migration-skey");
234
235 if (test_facility(169)) {
236 report_skip("storage key removal facility is active");
237 migrate_skip();
238 goto error;
239 }
240
241 parse_args(argc, argv);
242
243 switch (arg_test_to_run) {
244 case TEST_SEQUENTIAL:
245 test_skey_migration_sequential();
246 break;
247 case TEST_PARALLEL:
248 test_skey_migration_parallel();
249 break;
250 default:
251 print_usage();
252 migrate_skip();
253 break;
254 }
255
256 error:
257 report_prefix_pop();
258 return report_summary();
259 }
260