xref: /openbmc/qemu/hw/s390x/s390-skeys.c (revision b45c03f5)
1 /*
2  * s390 storage key device
3  *
4  * Copyright 2015 IBM Corp.
5  * Author(s): Jason J. Herne <jjherne@linux.vnet.ibm.com>
6  *
7  * This work is licensed under the terms of the GNU GPL, version 2 or (at
8  * your option) any later version. See the COPYING file in the top-level
9  * directory.
10  */
11 
12 #include "hw/boards.h"
13 #include "qmp-commands.h"
14 #include "migration/qemu-file.h"
15 #include "hw/s390x/storage-keys.h"
16 #include "qemu/error-report.h"
17 
18 #define S390_SKEYS_BUFFER_SIZE 131072  /* Room for 128k storage keys */
19 #define S390_SKEYS_SAVE_FLAG_EOS 0x01
20 #define S390_SKEYS_SAVE_FLAG_SKEYS 0x02
21 #define S390_SKEYS_SAVE_FLAG_ERROR 0x04
22 
23 S390SKeysState *s390_get_skeys_device(void)
24 {
25     S390SKeysState *ss;
26 
27     ss = S390_SKEYS(object_resolve_path_type("", TYPE_S390_SKEYS, NULL));
28     assert(ss);
29     return ss;
30 }
31 
32 void s390_skeys_init(void)
33 {
34     Object *obj;
35 
36     if (kvm_enabled()) {
37         obj = object_new(TYPE_KVM_S390_SKEYS);
38     } else {
39         obj = object_new(TYPE_QEMU_S390_SKEYS);
40     }
41     object_property_add_child(qdev_get_machine(), TYPE_S390_SKEYS,
42                               obj, NULL);
43     object_unref(obj);
44 
45     qdev_init_nofail(DEVICE(obj));
46 }
47 
48 static void write_keys(QEMUFile *f, uint8_t *keys, uint64_t startgfn,
49                        uint64_t count, Error **errp)
50 {
51     uint64_t curpage = startgfn;
52     uint64_t maxpage = curpage + count - 1;
53     const char *fmt = "page=%03" PRIx64 ": key(%d) => ACC=%X, FP=%d, REF=%d,"
54                       " ch=%d, reserved=%d\n";
55     char buf[128];
56     int len;
57 
58     for (; curpage <= maxpage; curpage++) {
59         uint8_t acc = (*keys & 0xF0) >> 4;
60         int fp =  (*keys & 0x08);
61         int ref = (*keys & 0x04);
62         int ch = (*keys & 0x02);
63         int res = (*keys & 0x01);
64 
65         len = snprintf(buf, sizeof(buf), fmt, curpage,
66                        *keys, acc, fp, ref, ch, res);
67         assert(len < sizeof(buf));
68         qemu_put_buffer(f, (uint8_t *)buf, len);
69         keys++;
70     }
71 }
72 
73 void hmp_info_skeys(Monitor *mon, const QDict *qdict)
74 {
75     S390SKeysState *ss = s390_get_skeys_device();
76     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
77     uint64_t addr = qdict_get_int(qdict, "addr");
78     uint8_t key;
79     int r;
80 
81     /* Quick check to see if guest is using storage keys*/
82     if (!skeyclass->skeys_enabled(ss)) {
83         monitor_printf(mon, "Error: This guest is not using storage keys\n");
84         return;
85     }
86 
87     r = skeyclass->get_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
88     if (r < 0) {
89         monitor_printf(mon, "Error: %s\n", strerror(-r));
90         return;
91     }
92 
93     monitor_printf(mon, "  key: 0x%X\n", key);
94 }
95 
96 void hmp_dump_skeys(Monitor *mon, const QDict *qdict)
97 {
98     const char *filename = qdict_get_str(qdict, "filename");
99     Error *err = NULL;
100 
101     qmp_dump_skeys(filename, &err);
102     if (err) {
103         monitor_printf(mon, "%s\n", error_get_pretty(err));
104         error_free(err);
105     }
106 }
107 
108 void qmp_dump_skeys(const char *filename, Error **errp)
109 {
110     S390SKeysState *ss = s390_get_skeys_device();
111     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
112     const uint64_t total_count = ram_size / TARGET_PAGE_SIZE;
113     uint64_t handled_count = 0, cur_count;
114     Error *lerr = NULL;
115     vaddr cur_gfn = 0;
116     uint8_t *buf;
117     int ret;
118     QEMUFile *f;
119 
120     /* Quick check to see if guest is using storage keys*/
121     if (!skeyclass->skeys_enabled(ss)) {
122         error_setg(errp, "This guest is not using storage keys - "
123                          "nothing to dump");
124         return;
125     }
126 
127     f = qemu_fopen(filename, "wb");
128     if (!f) {
129         error_setg_file_open(errp, errno, filename);
130         return;
131     }
132 
133     buf = g_try_malloc(S390_SKEYS_BUFFER_SIZE);
134     if (!buf) {
135         error_setg(errp, "Could not allocate memory");
136         goto out;
137     }
138 
139     /* we'll only dump initial memory for now */
140     while (handled_count < total_count) {
141         /* Calculate how many keys to ask for & handle overflow case */
142         cur_count = MIN(total_count - handled_count, S390_SKEYS_BUFFER_SIZE);
143 
144         ret = skeyclass->get_skeys(ss, cur_gfn, cur_count, buf);
145         if (ret < 0) {
146             error_setg(errp, "get_keys error %d", ret);
147             goto out_free;
148         }
149 
150         /* write keys to stream */
151         write_keys(f, buf, cur_gfn, cur_count, &lerr);
152         if (lerr) {
153             goto out_free;
154         }
155 
156         cur_gfn += cur_count;
157         handled_count += cur_count;
158     }
159 
160 out_free:
161     error_propagate(errp, lerr);
162     g_free(buf);
163 out:
164     qemu_fclose(f);
165 }
166 
167 static void qemu_s390_skeys_init(Object *obj)
168 {
169     QEMUS390SKeysState *skeys = QEMU_S390_SKEYS(obj);
170     MachineState *machine = MACHINE(qdev_get_machine());
171 
172     skeys->key_count = machine->maxram_size / TARGET_PAGE_SIZE;
173     skeys->keydata = g_malloc0(skeys->key_count);
174 }
175 
176 static int qemu_s390_skeys_enabled(S390SKeysState *ss)
177 {
178     return 1;
179 }
180 
181 /*
182  * TODO: for memory hotplug support qemu_s390_skeys_set and qemu_s390_skeys_get
183  * will have to make sure that the given gfn belongs to a memory region and not
184  * a memory hole.
185  */
186 static int qemu_s390_skeys_set(S390SKeysState *ss, uint64_t start_gfn,
187                               uint64_t count, uint8_t *keys)
188 {
189     QEMUS390SKeysState *skeydev = QEMU_S390_SKEYS(ss);
190     int i;
191 
192     /* Check for uint64 overflow and access beyond end of key data */
193     if (start_gfn + count > skeydev->key_count || start_gfn + count < count) {
194         error_report("Error: Setting storage keys for page beyond the end "
195                 "of memory: gfn=%" PRIx64 " count=%" PRId64 "\n", start_gfn,
196                 count);
197         return -EINVAL;
198     }
199 
200     for (i = 0; i < count; i++) {
201         skeydev->keydata[start_gfn + i] = keys[i];
202     }
203     return 0;
204 }
205 
206 static int qemu_s390_skeys_get(S390SKeysState *ss, uint64_t start_gfn,
207                                uint64_t count, uint8_t *keys)
208 {
209     QEMUS390SKeysState *skeydev = QEMU_S390_SKEYS(ss);
210     int i;
211 
212     /* Check for uint64 overflow and access beyond end of key data */
213     if (start_gfn + count > skeydev->key_count || start_gfn + count < count) {
214         error_report("Error: Getting storage keys for page beyond the end "
215                 "of memory: gfn=%" PRIx64 " count=%" PRId64 "\n", start_gfn,
216                 count);
217         return -EINVAL;
218     }
219 
220     for (i = 0; i < count; i++) {
221         keys[i] = skeydev->keydata[start_gfn + i];
222     }
223     return 0;
224 }
225 
226 static void qemu_s390_skeys_class_init(ObjectClass *oc, void *data)
227 {
228     S390SKeysClass *skeyclass = S390_SKEYS_CLASS(oc);
229 
230     skeyclass->skeys_enabled = qemu_s390_skeys_enabled;
231     skeyclass->get_skeys = qemu_s390_skeys_get;
232     skeyclass->set_skeys = qemu_s390_skeys_set;
233 }
234 
235 static const TypeInfo qemu_s390_skeys_info = {
236     .name          = TYPE_QEMU_S390_SKEYS,
237     .parent        = TYPE_S390_SKEYS,
238     .instance_init = qemu_s390_skeys_init,
239     .instance_size = sizeof(QEMUS390SKeysState),
240     .class_init    = qemu_s390_skeys_class_init,
241     .instance_size = sizeof(S390SKeysClass),
242 };
243 
244 static void s390_storage_keys_save(QEMUFile *f, void *opaque)
245 {
246     S390SKeysState *ss = S390_SKEYS(opaque);
247     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
248     uint64_t pages_left = ram_size / TARGET_PAGE_SIZE;
249     uint64_t read_count, eos = S390_SKEYS_SAVE_FLAG_EOS;
250     vaddr cur_gfn = 0;
251     int error = 0;
252     uint8_t *buf;
253 
254     if (!skeyclass->skeys_enabled(ss)) {
255         goto end_stream;
256     }
257 
258     buf = g_try_malloc(S390_SKEYS_BUFFER_SIZE);
259     if (!buf) {
260         error_report("storage key save could not allocate memory\n");
261         goto end_stream;
262     }
263 
264     /* We only support initial memory. Standby memory is not handled yet. */
265     qemu_put_be64(f, (cur_gfn * TARGET_PAGE_SIZE) | S390_SKEYS_SAVE_FLAG_SKEYS);
266     qemu_put_be64(f, pages_left);
267 
268     while (pages_left) {
269         read_count = MIN(pages_left, S390_SKEYS_BUFFER_SIZE);
270 
271         if (!error) {
272             error = skeyclass->get_skeys(ss, cur_gfn, read_count, buf);
273             if (error) {
274                 /*
275                  * If error: we want to fill the stream with valid data instead
276                  * of stopping early so we pad the stream with 0x00 values and
277                  * use S390_SKEYS_SAVE_FLAG_ERROR to indicate failure to the
278                  * reading side.
279                  */
280                 error_report("S390_GET_KEYS error %d\n", error);
281                 memset(buf, 0, S390_SKEYS_BUFFER_SIZE);
282                 eos = S390_SKEYS_SAVE_FLAG_ERROR;
283             }
284         }
285 
286         qemu_put_buffer(f, buf, read_count);
287         cur_gfn += read_count;
288         pages_left -= read_count;
289     }
290 
291     g_free(buf);
292 end_stream:
293     qemu_put_be64(f, eos);
294 }
295 
296 static int s390_storage_keys_load(QEMUFile *f, void *opaque, int version_id)
297 {
298     S390SKeysState *ss = S390_SKEYS(opaque);
299     S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
300     int ret = 0;
301 
302     while (!ret) {
303         ram_addr_t addr;
304         int flags;
305 
306         addr = qemu_get_be64(f);
307         flags = addr & ~TARGET_PAGE_MASK;
308         addr &= TARGET_PAGE_MASK;
309 
310         switch (flags) {
311         case S390_SKEYS_SAVE_FLAG_SKEYS: {
312             const uint64_t total_count = qemu_get_be64(f);
313             uint64_t handled_count = 0, cur_count;
314             uint64_t cur_gfn = addr / TARGET_PAGE_SIZE;
315             uint8_t *buf = g_try_malloc(S390_SKEYS_BUFFER_SIZE);
316 
317             if (!buf) {
318                 error_report("storage key load could not allocate memory\n");
319                 ret = -ENOMEM;
320                 break;
321             }
322 
323             while (handled_count < total_count) {
324                 cur_count = MIN(total_count - handled_count,
325                                 S390_SKEYS_BUFFER_SIZE);
326                 qemu_get_buffer(f, buf, cur_count);
327 
328                 ret = skeyclass->set_skeys(ss, cur_gfn, cur_count, buf);
329                 if (ret < 0) {
330                     error_report("S390_SET_KEYS error %d\n", ret);
331                     break;
332                 }
333                 handled_count += cur_count;
334                 cur_gfn += cur_count;
335             }
336             g_free(buf);
337             break;
338         }
339         case S390_SKEYS_SAVE_FLAG_ERROR: {
340             error_report("Storage key data is incomplete");
341             ret = -EINVAL;
342             break;
343         }
344         case S390_SKEYS_SAVE_FLAG_EOS:
345             /* normal exit */
346             return 0;
347         default:
348             error_report("Unexpected storage key flag data: %#x", flags);
349             ret = -EINVAL;
350         }
351     }
352 
353     return ret;
354 }
355 
356 static inline bool s390_skeys_get_migration_enabled(Object *obj, Error **errp)
357 {
358     S390SKeysState *ss = S390_SKEYS(obj);
359 
360     return ss->migration_enabled;
361 }
362 
363 static inline void s390_skeys_set_migration_enabled(Object *obj, bool value,
364                                             Error **errp)
365 {
366     S390SKeysState *ss = S390_SKEYS(obj);
367 
368     /* Prevent double registration of savevm handler */
369     if (ss->migration_enabled == value) {
370         return;
371     }
372 
373     ss->migration_enabled = value;
374 
375     if (ss->migration_enabled) {
376         register_savevm(NULL, TYPE_S390_SKEYS, 0, 1, s390_storage_keys_save,
377                         s390_storage_keys_load, ss);
378     } else {
379         unregister_savevm(DEVICE(ss), TYPE_S390_SKEYS, ss);
380     }
381 }
382 
383 static void s390_skeys_instance_init(Object *obj)
384 {
385     object_property_add_bool(obj, "migration-enabled",
386                              s390_skeys_get_migration_enabled,
387                              s390_skeys_set_migration_enabled, NULL);
388     object_property_set_bool(obj, true, "migration-enabled", NULL);
389 }
390 
391 static void s390_skeys_class_init(ObjectClass *oc, void *data)
392 {
393     DeviceClass *dc = DEVICE_CLASS(oc);
394 
395     dc->hotpluggable = false;
396     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
397 }
398 
399 static const TypeInfo s390_skeys_info = {
400     .name          = TYPE_S390_SKEYS,
401     .parent        = TYPE_DEVICE,
402     .instance_init = s390_skeys_instance_init,
403     .instance_size = sizeof(S390SKeysState),
404     .class_init    = s390_skeys_class_init,
405     .class_size    = sizeof(S390SKeysClass),
406     .abstract = true,
407 };
408 
409 static void qemu_s390_skeys_register_types(void)
410 {
411     type_register_static(&s390_skeys_info);
412     type_register_static(&qemu_s390_skeys_info);
413 }
414 
415 type_init(qemu_s390_skeys_register_types)
416