xref: /qemu/hw/intc/s390_flic_kvm.c (revision 52ea63de) 
1 /*
2  * QEMU S390x KVM floating interrupt controller (flic)
3  *
4  * Copyright 2014 IBM Corp.
5  * Author(s): Jens Freimann <jfrei@linux.vnet.ibm.com>
6  *            Cornelia Huck <cornelia.huck@de.ibm.com>
7  *
8  * This work is licensed under the terms of the GNU GPL, version 2 or (at
9  * your option) any later version. See the COPYING file in the top-level
10  * directory.
11  */
12 
13 #include "qemu/osdep.h"
14 #include "qemu-common.h"
15 #include "cpu.h"
16 #include <sys/ioctl.h>
17 #include "qemu/error-report.h"
18 #include "hw/sysbus.h"
19 #include "sysemu/kvm.h"
20 #include "migration/qemu-file.h"
21 #include "hw/s390x/s390_flic.h"
22 #include "hw/s390x/adapter.h"
23 #include "trace.h"
24 
25 #define FLIC_SAVE_INITIAL_SIZE getpagesize()
26 #define FLIC_FAILED (-1UL)
27 #define FLIC_SAVEVM_VERSION 1
28 
29 typedef struct KVMS390FLICState {
30     S390FLICState parent_obj;
31 
32     uint32_t fd;
33     bool clear_io_supported;
34 } KVMS390FLICState;
35 
36 DeviceState *s390_flic_kvm_create(void)
37 {
38     DeviceState *dev = NULL;
39 
40     if (kvm_enabled()) {
41         dev = qdev_create(NULL, TYPE_KVM_S390_FLIC);
42         object_property_add_child(qdev_get_machine(), TYPE_KVM_S390_FLIC,
43                                   OBJECT(dev), NULL);
44     }
45     return dev;
46 }
47 
48 /**
49  * flic_get_all_irqs - store all pending irqs in buffer
50  * @buf: pointer to buffer which is passed to kernel
51  * @len: length of buffer
52  * @flic: pointer to flic device state
53  *
54  * Returns: -ENOMEM if buffer is too small,
55  * -EINVAL if attr.group is invalid,
56  * -EFAULT if copying to userspace failed,
57  * on success return number of stored interrupts
58  */
59 static int flic_get_all_irqs(KVMS390FLICState *flic,
60                              void *buf, int len)
61 {
62     struct kvm_device_attr attr = {
63         .group = KVM_DEV_FLIC_GET_ALL_IRQS,
64         .addr = (uint64_t) buf,
65         .attr = len,
66     };
67     int rc;
68 
69     rc = ioctl(flic->fd, KVM_GET_DEVICE_ATTR, &attr);
70 
71     return rc == -1 ? -errno : rc;
72 }
73 
74 static void flic_enable_pfault(KVMS390FLICState *flic)
75 {
76     struct kvm_device_attr attr = {
77         .group = KVM_DEV_FLIC_APF_ENABLE,
78     };
79     int rc;
80 
81     rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
82 
83     if (rc) {
84         fprintf(stderr, "flic: couldn't enable pfault\n");
85     }
86 }
87 
88 static void flic_disable_wait_pfault(KVMS390FLICState *flic)
89 {
90     struct kvm_device_attr attr = {
91         .group = KVM_DEV_FLIC_APF_DISABLE_WAIT,
92     };
93     int rc;
94 
95     rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
96 
97     if (rc) {
98         fprintf(stderr, "flic: couldn't disable pfault\n");
99     }
100 }
101 
102 /** flic_enqueue_irqs - returns 0 on success
103  * @buf: pointer to buffer which is passed to kernel
104  * @len: length of buffer
105  * @flic: pointer to flic device state
106  *
107  * Returns: -EINVAL if attr.group is unknown
108  */
109 static int flic_enqueue_irqs(void *buf, uint64_t len,
110                             KVMS390FLICState *flic)
111 {
112     int rc;
113     struct kvm_device_attr attr = {
114         .group = KVM_DEV_FLIC_ENQUEUE,
115         .addr = (uint64_t) buf,
116         .attr = len,
117     };
118 
119     rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
120 
121     return rc ? -errno : 0;
122 }
123 
124 int kvm_s390_inject_flic(struct kvm_s390_irq *irq)
125 {
126     static KVMS390FLICState *flic;
127 
128     if (unlikely(!flic)) {
129         flic = KVM_S390_FLIC(s390_get_flic());
130     }
131     return flic_enqueue_irqs(irq, sizeof(*irq), flic);
132 }
133 
134 static int kvm_s390_clear_io_flic(S390FLICState *fs, uint16_t subchannel_id,
135                            uint16_t subchannel_nr)
136 {
137     KVMS390FLICState *flic = KVM_S390_FLIC(fs);
138     int rc;
139     uint32_t sid = subchannel_id << 16 | subchannel_nr;
140     struct kvm_device_attr attr = {
141         .group = KVM_DEV_FLIC_CLEAR_IO_IRQ,
142         .addr = (uint64_t) &sid,
143         .attr = sizeof(sid),
144     };
145     if (unlikely(!flic->clear_io_supported)) {
146         return -ENOSYS;
147     }
148     rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
149     return rc ? -errno : 0;
150 }
151 
152 /**
153  * __get_all_irqs - store all pending irqs in buffer
154  * @flic: pointer to flic device state
155  * @buf: pointer to pointer to a buffer
156  * @len: length of buffer
157  *
158  * Returns: return value of flic_get_all_irqs
159  * Note: Retry and increase buffer size until flic_get_all_irqs
160  * either returns a value >= 0 or a negative error code.
161  * -ENOMEM is an exception, which means the buffer is too small
162  * and we should try again. Other negative error codes can be
163  * -EFAULT and -EINVAL which we ignore at this point
164  */
165 static int __get_all_irqs(KVMS390FLICState *flic,
166                           void **buf, int len)
167 {
168     int r;
169 
170     do {
171         /* returns -ENOMEM if buffer is too small and number
172          * of queued interrupts on success */
173         r = flic_get_all_irqs(flic, *buf, len);
174         if (r >= 0) {
175             break;
176         }
177         len *= 2;
178         *buf = g_try_realloc(*buf, len);
179         if (!buf) {
180             return -ENOMEM;
181         }
182     } while (r == -ENOMEM && len <= KVM_S390_FLIC_MAX_BUFFER);
183 
184     return r;
185 }
186 
187 static int kvm_s390_register_io_adapter(S390FLICState *fs, uint32_t id,
188                                         uint8_t isc, bool swap,
189                                         bool is_maskable)
190 {
191     struct kvm_s390_io_adapter adapter = {
192         .id = id,
193         .isc = isc,
194         .maskable = is_maskable,
195         .swap = swap,
196     };
197     KVMS390FLICState *flic = KVM_S390_FLIC(fs);
198     int r, ret;
199     struct kvm_device_attr attr = {
200         .group = KVM_DEV_FLIC_ADAPTER_REGISTER,
201         .addr = (uint64_t)&adapter,
202     };
203 
204     if (!kvm_check_extension(kvm_state, KVM_CAP_IRQ_ROUTING)) {
205         /* nothing to do */
206         return 0;
207     }
208 
209     r = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
210 
211     ret = r ? -errno : 0;
212     return ret;
213 }
214 
215 static int kvm_s390_io_adapter_map(S390FLICState *fs, uint32_t id,
216                                    uint64_t map_addr, bool do_map)
217 {
218     struct kvm_s390_io_adapter_req req = {
219         .id = id,
220         .type = do_map ? KVM_S390_IO_ADAPTER_MAP : KVM_S390_IO_ADAPTER_UNMAP,
221         .addr = map_addr,
222     };
223     struct kvm_device_attr attr = {
224         .group = KVM_DEV_FLIC_ADAPTER_MODIFY,
225         .addr = (uint64_t)&req,
226     };
227     KVMS390FLICState *flic = KVM_S390_FLIC(fs);
228     int r;
229 
230     if (!kvm_check_extension(kvm_state, KVM_CAP_IRQ_ROUTING)) {
231         /* nothing to do */
232         return 0;
233     }
234 
235     r = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
236     return r ? -errno : 0;
237 }
238 
239 static int kvm_s390_add_adapter_routes(S390FLICState *fs,
240                                        AdapterRoutes *routes)
241 {
242     int ret, i;
243     uint64_t ind_offset = routes->adapter.ind_offset;
244 
245     for (i = 0; i < routes->num_routes; i++) {
246         ret = kvm_irqchip_add_adapter_route(kvm_state, &routes->adapter);
247         if (ret < 0) {
248             goto out_undo;
249         }
250         routes->gsi[i] = ret;
251         routes->adapter.ind_offset++;
252     }
253     kvm_irqchip_commit_routes(kvm_state);
254 
255     /* Restore passed-in structure to original state. */
256     routes->adapter.ind_offset = ind_offset;
257     return 0;
258 out_undo:
259     while (--i >= 0) {
260         kvm_irqchip_release_virq(kvm_state, routes->gsi[i]);
261         routes->gsi[i] = -1;
262     }
263     routes->adapter.ind_offset = ind_offset;
264     return ret;
265 }
266 
267 static void kvm_s390_release_adapter_routes(S390FLICState *fs,
268                                             AdapterRoutes *routes)
269 {
270     int i;
271 
272     for (i = 0; i < routes->num_routes; i++) {
273         if (routes->gsi[i] >= 0) {
274             kvm_irqchip_release_virq(kvm_state, routes->gsi[i]);
275             routes->gsi[i] = -1;
276         }
277     }
278 }
279 
280 /**
281  * kvm_flic_save - Save pending floating interrupts
282  * @f: QEMUFile containing migration state
283  * @opaque: pointer to flic device state
284  *
285  * Note: Pass buf and len to kernel. Start with one page and
286  * increase until buffer is sufficient or maxium size is
287  * reached
288  */
289 static void kvm_flic_save(QEMUFile *f, void *opaque)
290 {
291     KVMS390FLICState *flic = opaque;
292     int len = FLIC_SAVE_INITIAL_SIZE;
293     void *buf;
294     int count;
295 
296     flic_disable_wait_pfault((struct KVMS390FLICState *) opaque);
297 
298     buf = g_try_malloc0(len);
299     if (!buf) {
300         /* Storing FLIC_FAILED into the count field here will cause the
301          * target system to fail when attempting to load irqs from the
302          * migration state */
303         error_report("flic: couldn't allocate memory");
304         qemu_put_be64(f, FLIC_FAILED);
305         return;
306     }
307 
308     count = __get_all_irqs(flic, &buf, len);
309     if (count < 0) {
310         error_report("flic: couldn't retrieve irqs from kernel, rc %d",
311                      count);
312         /* Storing FLIC_FAILED into the count field here will cause the
313          * target system to fail when attempting to load irqs from the
314          * migration state */
315         qemu_put_be64(f, FLIC_FAILED);
316     } else {
317         qemu_put_be64(f, count);
318         qemu_put_buffer(f, (uint8_t *) buf,
319                         count * sizeof(struct kvm_s390_irq));
320     }
321     g_free(buf);
322 }
323 
324 /**
325  * kvm_flic_load - Load pending floating interrupts
326  * @f: QEMUFile containing migration state
327  * @opaque: pointer to flic device state
328  * @version_id: version id for migration
329  *
330  * Returns: value of flic_enqueue_irqs, -EINVAL on error
331  * Note: Do nothing when no interrupts where stored
332  * in QEMUFile
333  */
334 static int kvm_flic_load(QEMUFile *f, void *opaque, int version_id)
335 {
336     uint64_t len = 0;
337     uint64_t count = 0;
338     void *buf = NULL;
339     int r = 0;
340 
341     if (version_id != FLIC_SAVEVM_VERSION) {
342         r = -EINVAL;
343         goto out;
344     }
345 
346     flic_enable_pfault((struct KVMS390FLICState *) opaque);
347 
348     count = qemu_get_be64(f);
349     len = count * sizeof(struct kvm_s390_irq);
350     if (count == FLIC_FAILED) {
351         r = -EINVAL;
352         goto out;
353     }
354     if (count == 0) {
355         r = 0;
356         goto out;
357     }
358     buf = g_try_malloc0(len);
359     if (!buf) {
360         r = -ENOMEM;
361         goto out;
362     }
363 
364     if (qemu_get_buffer(f, (uint8_t *) buf, len) != len) {
365         r = -EINVAL;
366         goto out_free;
367     }
368     r = flic_enqueue_irqs(buf, len, (struct KVMS390FLICState *) opaque);
369 
370 out_free:
371     g_free(buf);
372 out:
373     return r;
374 }
375 
376 static void kvm_s390_flic_realize(DeviceState *dev, Error **errp)
377 {
378     KVMS390FLICState *flic_state = KVM_S390_FLIC(dev);
379     struct kvm_create_device cd = {0};
380     struct kvm_device_attr test_attr = {0};
381     int ret;
382 
383     flic_state->fd = -1;
384     if (!kvm_check_extension(kvm_state, KVM_CAP_DEVICE_CTRL)) {
385         trace_flic_no_device_api(errno);
386         return;
387     }
388 
389     cd.type = KVM_DEV_TYPE_FLIC;
390     ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd);
391     if (ret < 0) {
392         trace_flic_create_device(errno);
393         return;
394     }
395     flic_state->fd = cd.fd;
396 
397     /* Check clear_io_irq support */
398     test_attr.group = KVM_DEV_FLIC_CLEAR_IO_IRQ;
399     flic_state->clear_io_supported = !ioctl(flic_state->fd,
400                                             KVM_HAS_DEVICE_ATTR, test_attr);
401 
402     /* Register savevm handler for floating interrupts */
403     register_savevm(NULL, "s390-flic", 0, 1, kvm_flic_save,
404                     kvm_flic_load, (void *) flic_state);
405 }
406 
407 static void kvm_s390_flic_unrealize(DeviceState *dev, Error **errp)
408 {
409     KVMS390FLICState *flic_state = KVM_S390_FLIC(dev);
410 
411     unregister_savevm(DEVICE(flic_state), "s390-flic", flic_state);
412 }
413 
414 static void kvm_s390_flic_reset(DeviceState *dev)
415 {
416     KVMS390FLICState *flic = KVM_S390_FLIC(dev);
417     struct kvm_device_attr attr = {
418         .group = KVM_DEV_FLIC_CLEAR_IRQS,
419     };
420     int rc = 0;
421 
422     if (flic->fd == -1) {
423         return;
424     }
425 
426     flic_disable_wait_pfault(flic);
427 
428     rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
429     if (rc) {
430         trace_flic_reset_failed(errno);
431     }
432 
433     flic_enable_pfault(flic);
434 }
435 
436 static void kvm_s390_flic_class_init(ObjectClass *oc, void *data)
437 {
438     DeviceClass *dc = DEVICE_CLASS(oc);
439     S390FLICStateClass *fsc = S390_FLIC_COMMON_CLASS(oc);
440 
441     dc->realize = kvm_s390_flic_realize;
442     dc->unrealize = kvm_s390_flic_unrealize;
443     dc->reset = kvm_s390_flic_reset;
444     fsc->register_io_adapter = kvm_s390_register_io_adapter;
445     fsc->io_adapter_map = kvm_s390_io_adapter_map;
446     fsc->add_adapter_routes = kvm_s390_add_adapter_routes;
447     fsc->release_adapter_routes = kvm_s390_release_adapter_routes;
448     fsc->clear_io_irq = kvm_s390_clear_io_flic;
449 }
450 
451 static const TypeInfo kvm_s390_flic_info = {
452     .name          = TYPE_KVM_S390_FLIC,
453     .parent        = TYPE_S390_FLIC_COMMON,
454     .instance_size = sizeof(KVMS390FLICState),
455     .class_init    = kvm_s390_flic_class_init,
456 };
457 
458 static void kvm_s390_flic_register_types(void)
459 {
460     type_register_static(&kvm_s390_flic_info);
461 }
462 
463 type_init(kvm_s390_flic_register_types)
464