Linux debugging

Check our new training course

Linux debugging, tracing, profiling & perf. analysis

Check our new training course
with Creative Commons CC-BY-SA
lecture and lab materials

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
/*
 * QEMU S390x KVM floating interrupt controller (flic)
 *
 * Copyright 2014 IBM Corp.
 * Author(s): Jens Freimann <jfrei@linux.vnet.ibm.com>
 *            Cornelia Huck <cornelia.huck@de.ibm.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or (at
 * your option) any later version. See the COPYING file in the top-level
 * directory.
 */

#include <sys/ioctl.h>
#include "qemu/error-report.h"
#include "hw/sysbus.h"
#include "sysemu/kvm.h"
#include "migration/qemu-file.h"
#include "hw/s390x/s390_flic.h"
#include "hw/s390x/adapter.h"
#include "trace.h"

#define FLIC_SAVE_INITIAL_SIZE getpagesize()
#define FLIC_FAILED (-1UL)
#define FLIC_SAVEVM_VERSION 1

typedef struct KVMS390FLICState {
    S390FLICState parent_obj;

    uint32_t fd;
} KVMS390FLICState;

DeviceState *s390_flic_kvm_create(void)
{
    DeviceState *dev = NULL;

    if (kvm_enabled()) {
        dev = qdev_create(NULL, TYPE_KVM_S390_FLIC);
        object_property_add_child(qdev_get_machine(), TYPE_KVM_S390_FLIC,
                                  OBJECT(dev), NULL);
    }
    return dev;
}

/**
 * flic_get_all_irqs - store all pending irqs in buffer
 * @buf: pointer to buffer which is passed to kernel
 * @len: length of buffer
 * @flic: pointer to flic device state
 *
 * Returns: -ENOMEM if buffer is too small,
 * -EINVAL if attr.group is invalid,
 * -EFAULT if copying to userspace failed,
 * on success return number of stored interrupts
 */
static int flic_get_all_irqs(KVMS390FLICState *flic,
                             void *buf, int len)
{
    struct kvm_device_attr attr = {
        .group = KVM_DEV_FLIC_GET_ALL_IRQS,
        .addr = (uint64_t) buf,
        .attr = len,
    };
    int rc;

    rc = ioctl(flic->fd, KVM_GET_DEVICE_ATTR, &attr);

    return rc == -1 ? -errno : rc;
}

static void flic_enable_pfault(KVMS390FLICState *flic)
{
    struct kvm_device_attr attr = {
        .group = KVM_DEV_FLIC_APF_ENABLE,
    };
    int rc;

    rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);

    if (rc) {
        fprintf(stderr, "flic: couldn't enable pfault\n");
    }
}

static void flic_disable_wait_pfault(KVMS390FLICState *flic)
{
    struct kvm_device_attr attr = {
        .group = KVM_DEV_FLIC_APF_DISABLE_WAIT,
    };
    int rc;

    rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);

    if (rc) {
        fprintf(stderr, "flic: couldn't disable pfault\n");
    }
}

/** flic_enqueue_irqs - returns 0 on success
 * @buf: pointer to buffer which is passed to kernel
 * @len: length of buffer
 * @flic: pointer to flic device state
 *
 * Returns: -EINVAL if attr.group is unknown
 */
static int flic_enqueue_irqs(void *buf, uint64_t len,
                            KVMS390FLICState *flic)
{
    int rc;
    struct kvm_device_attr attr = {
        .group = KVM_DEV_FLIC_ENQUEUE,
        .addr = (uint64_t) buf,
        .attr = len,
    };

    rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);

    return rc ? -errno : 0;
}

int kvm_s390_inject_flic(struct kvm_s390_irq *irq)
{
    static KVMS390FLICState *flic;

    if (unlikely(!flic)) {
        flic = KVM_S390_FLIC(s390_get_flic());
    }
    return flic_enqueue_irqs(irq, sizeof(*irq), flic);
}

/**
 * __get_all_irqs - store all pending irqs in buffer
 * @flic: pointer to flic device state
 * @buf: pointer to pointer to a buffer
 * @len: length of buffer
 *
 * Returns: return value of flic_get_all_irqs
 * Note: Retry and increase buffer size until flic_get_all_irqs
 * either returns a value >= 0 or a negative error code.
 * -ENOMEM is an exception, which means the buffer is too small
 * and we should try again. Other negative error codes can be
 * -EFAULT and -EINVAL which we ignore at this point
 */
static int __get_all_irqs(KVMS390FLICState *flic,
                          void **buf, int len)
{
    int r;

    do {
        /* returns -ENOMEM if buffer is too small and number
         * of queued interrupts on success */
        r = flic_get_all_irqs(flic, *buf, len);
        if (r >= 0) {
            break;
        }
        len *= 2;
        *buf = g_try_realloc(*buf, len);
        if (!buf) {
            return -ENOMEM;
        }
    } while (r == -ENOMEM && len <= KVM_S390_FLIC_MAX_BUFFER);

    return r;
}

static int kvm_s390_register_io_adapter(S390FLICState *fs, uint32_t id,
                                        uint8_t isc, bool swap,
                                        bool is_maskable)
{
    struct kvm_s390_io_adapter adapter = {
        .id = id,
        .isc = isc,
        .maskable = is_maskable,
        .swap = swap,
    };
    KVMS390FLICState *flic = KVM_S390_FLIC(fs);
    int r, ret;
    struct kvm_device_attr attr = {
        .group = KVM_DEV_FLIC_ADAPTER_REGISTER,
        .addr = (uint64_t)&adapter,
    };

    if (!kvm_check_extension(kvm_state, KVM_CAP_IRQ_ROUTING)) {
        /* nothing to do */
        return 0;
    }

    r = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);

    ret = r ? -errno : 0;
    return ret;
}

static int kvm_s390_io_adapter_map(S390FLICState *fs, uint32_t id,
                                   uint64_t map_addr, bool do_map)
{
    struct kvm_s390_io_adapter_req req = {
        .id = id,
        .type = do_map ? KVM_S390_IO_ADAPTER_MAP : KVM_S390_IO_ADAPTER_UNMAP,
        .addr = map_addr,
    };
    struct kvm_device_attr attr = {
        .group = KVM_DEV_FLIC_ADAPTER_MODIFY,
        .addr = (uint64_t)&req,
    };
    KVMS390FLICState *flic = KVM_S390_FLIC(fs);
    int r;

    if (!kvm_check_extension(kvm_state, KVM_CAP_IRQ_ROUTING)) {
        /* nothing to do */
        return 0;
    }

    r = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
    return r ? -errno : 0;
}

static int kvm_s390_add_adapter_routes(S390FLICState *fs,
                                       AdapterRoutes *routes)
{
    int ret, i;
    uint64_t ind_offset = routes->adapter.ind_offset;

    for (i = 0; i < routes->num_routes; i++) {
        ret = kvm_irqchip_add_adapter_route(kvm_state, &routes->adapter);
        if (ret < 0) {
            goto out_undo;
        }
        routes->gsi[i] = ret;
        routes->adapter.ind_offset++;
    }
    /* Restore passed-in structure to original state. */
    routes->adapter.ind_offset = ind_offset;
    return 0;
out_undo:
    while (--i >= 0) {
        kvm_irqchip_release_virq(kvm_state, routes->gsi[i]);
        routes->gsi[i] = -1;
    }
    routes->adapter.ind_offset = ind_offset;
    return ret;
}

static void kvm_s390_release_adapter_routes(S390FLICState *fs,
                                            AdapterRoutes *routes)
{
    int i;

    for (i = 0; i < routes->num_routes; i++) {
        if (routes->gsi[i] >= 0) {
            kvm_irqchip_release_virq(kvm_state, routes->gsi[i]);
            routes->gsi[i] = -1;
        }
    }
}

/**
 * kvm_flic_save - Save pending floating interrupts
 * @f: QEMUFile containing migration state
 * @opaque: pointer to flic device state
 *
 * Note: Pass buf and len to kernel. Start with one page and
 * increase until buffer is sufficient or maxium size is
 * reached
 */
static void kvm_flic_save(QEMUFile *f, void *opaque)
{
    KVMS390FLICState *flic = opaque;
    int len = FLIC_SAVE_INITIAL_SIZE;
    void *buf;
    int count;

    flic_disable_wait_pfault((struct KVMS390FLICState *) opaque);

    buf = g_try_malloc0(len);
    if (!buf) {
        /* Storing FLIC_FAILED into the count field here will cause the
         * target system to fail when attempting to load irqs from the
         * migration state */
        error_report("flic: couldn't allocate memory");
        qemu_put_be64(f, FLIC_FAILED);
        return;
    }

    count = __get_all_irqs(flic, &buf, len);
    if (count < 0) {
        error_report("flic: couldn't retrieve irqs from kernel, rc %d",
                     count);
        /* Storing FLIC_FAILED into the count field here will cause the
         * target system to fail when attempting to load irqs from the
         * migration state */
        qemu_put_be64(f, FLIC_FAILED);
    } else {
        qemu_put_be64(f, count);
        qemu_put_buffer(f, (uint8_t *) buf,
                        count * sizeof(struct kvm_s390_irq));
    }
    g_free(buf);
}

/**
 * kvm_flic_load - Load pending floating interrupts
 * @f: QEMUFile containing migration state
 * @opaque: pointer to flic device state
 * @version_id: version id for migration
 *
 * Returns: value of flic_enqueue_irqs, -EINVAL on error
 * Note: Do nothing when no interrupts where stored
 * in QEMUFile
 */
static int kvm_flic_load(QEMUFile *f, void *opaque, int version_id)
{
    uint64_t len = 0;
    uint64_t count = 0;
    void *buf = NULL;
    int r = 0;

    if (version_id != FLIC_SAVEVM_VERSION) {
        r = -EINVAL;
        goto out;
    }

    flic_enable_pfault((struct KVMS390FLICState *) opaque);

    count = qemu_get_be64(f);
    len = count * sizeof(struct kvm_s390_irq);
    if (count == FLIC_FAILED) {
        r = -EINVAL;
        goto out;
    }
    if (count == 0) {
        r = 0;
        goto out;
    }
    buf = g_try_malloc0(len);
    if (!buf) {
        r = -ENOMEM;
        goto out;
    }

    if (qemu_get_buffer(f, (uint8_t *) buf, len) != len) {
        r = -EINVAL;
        goto out_free;
    }
    r = flic_enqueue_irqs(buf, len, (struct KVMS390FLICState *) opaque);

out_free:
    g_free(buf);
out:
    return r;
}

static void kvm_s390_flic_realize(DeviceState *dev, Error **errp)
{
    KVMS390FLICState *flic_state = KVM_S390_FLIC(dev);
    struct kvm_create_device cd = {0};
    int ret;

    flic_state->fd = -1;
    if (!kvm_check_extension(kvm_state, KVM_CAP_DEVICE_CTRL)) {
        trace_flic_no_device_api(errno);
        return;
    }

    cd.type = KVM_DEV_TYPE_FLIC;
    ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd);
    if (ret < 0) {
        trace_flic_create_device(errno);
        return;
    }
    flic_state->fd = cd.fd;

    /* Register savevm handler for floating interrupts */
    register_savevm(NULL, "s390-flic", 0, 1, kvm_flic_save,
                    kvm_flic_load, (void *) flic_state);
}

static void kvm_s390_flic_unrealize(DeviceState *dev, Error **errp)
{
    KVMS390FLICState *flic_state = KVM_S390_FLIC(dev);

    unregister_savevm(DEVICE(flic_state), "s390-flic", flic_state);
}

static void kvm_s390_flic_reset(DeviceState *dev)
{
    KVMS390FLICState *flic = KVM_S390_FLIC(dev);
    struct kvm_device_attr attr = {
        .group = KVM_DEV_FLIC_CLEAR_IRQS,
    };
    int rc = 0;

    if (flic->fd == -1) {
        return;
    }

    flic_disable_wait_pfault(flic);

    rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
    if (rc) {
        trace_flic_reset_failed(errno);
    }

    flic_enable_pfault(flic);
}

static void kvm_s390_flic_class_init(ObjectClass *oc, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(oc);
    S390FLICStateClass *fsc = S390_FLIC_COMMON_CLASS(oc);

    dc->realize = kvm_s390_flic_realize;
    dc->unrealize = kvm_s390_flic_unrealize;
    dc->reset = kvm_s390_flic_reset;
    fsc->register_io_adapter = kvm_s390_register_io_adapter;
    fsc->io_adapter_map = kvm_s390_io_adapter_map;
    fsc->add_adapter_routes = kvm_s390_add_adapter_routes;
    fsc->release_adapter_routes = kvm_s390_release_adapter_routes;
}

static const TypeInfo kvm_s390_flic_info = {
    .name          = TYPE_KVM_S390_FLIC,
    .parent        = TYPE_S390_FLIC_COMMON,
    .instance_size = sizeof(KVMS390FLICState),
    .class_init    = kvm_s390_flic_class_init,
};

static void kvm_s390_flic_register_types(void)
{
    type_register_static(&kvm_s390_flic_info);
}

type_init(kvm_s390_flic_register_types)