aboutsummaryrefslogtreecommitdiff
path: root/pc-bios/s390-ccw/virtio.c
blob: 1d34e8c1aad782dad31fb406404200be464e8237 (plain)
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
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
/*
 * Virtio driver bits
 *
 * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
 *
 * 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 "s390-ccw.h"
#include "virtio.h"
#include "virtio-scsi.h"

#define VRING_WAIT_REPLY_TIMEOUT 3

static VRing block[VIRTIO_MAX_VQS];
static char ring_area[VIRTIO_RING_SIZE * VIRTIO_MAX_VQS]
                     __attribute__((__aligned__(PAGE_SIZE)));

static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));

static VDev vdev = {
    .nr_vqs = 1,
    .vrings = block,
    .cmd_vr_idx = 0,
    .ring_area = ring_area,
    .wait_reply_timeout = VRING_WAIT_REPLY_TIMEOUT,
    .schid = { .one = 1 },
    .scsi_block_size = VIRTIO_SCSI_BLOCK_SIZE,
    .blk_factor = 1,
};

VDev *virtio_get_device(void)
{
    return &vdev;
}

VirtioDevType virtio_get_device_type(void)
{
    return vdev.senseid.cu_model;
}

/* virtio spec v1.0 para 4.3.3.2 */
static long kvm_hypercall(unsigned long nr, unsigned long param1,
                          unsigned long param2, unsigned long param3)
{
    register ulong r_nr asm("1") = nr;
    register ulong r_param1 asm("2") = param1;
    register ulong r_param2 asm("3") = param2;
    register ulong r_param3 asm("4") = param3;
    register long retval asm("2");

    asm volatile ("diag 2,4,0x500"
                  : "=d" (retval)
                  : "d" (r_nr), "0" (r_param1), "r"(r_param2), "d"(r_param3)
                  : "memory", "cc");

    return retval;
}

static long virtio_notify(SubChannelId schid, int vq_idx, long cookie)
{
    return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid,
                         vq_idx, cookie);
}

/***********************************************
 *             Virtio functions                *
 ***********************************************/

static int drain_irqs(SubChannelId schid)
{
    Irb irb = {};
    int r = 0;

    while (1) {
        /* FIXME: make use of TPI, for that enable subchannel and isc */
        if (tsch(schid, &irb)) {
            /* Might want to differentiate error codes later on. */
            if (irb.scsw.cstat) {
                r = -EIO;
            } else if (irb.scsw.dstat != 0xc) {
                r = -EIO;
            }
            return r;
        }
    }
}

static int run_ccw(VDev *vdev, int cmd, void *ptr, int len)
{
    Ccw1 ccw = {};
    CmdOrb orb = {};
    Schib schib;
    int r;

    /* start command processing */
    stsch_err(vdev->schid, &schib);
    schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
    msch(vdev->schid, &schib);

    /* start subchannel command */
    orb.fmt = 1;
    orb.cpa = (u32)(long)&ccw;
    orb.lpm = 0x80;

    ccw.cmd_code = cmd;
    ccw.cda = (long)ptr;
    ccw.count = len;

    r = ssch(vdev->schid, &orb);
    /*
     * XXX Wait until device is done processing the CCW. For now we can
     *     assume that a simple tsch will have finished the CCW processing,
     *     but the architecture allows for asynchronous operation
     */
    if (!r) {
        r = drain_irqs(vdev->schid);
    }
    return r;
}

static void vring_init(VRing *vr, VqInfo *info)
{
    void *p = (void *) info->queue;

    debug_print_addr("init p", p);
    vr->id = info->index;
    vr->num = info->num;
    vr->desc = p;
    vr->avail = p + info->num * sizeof(VRingDesc);
    vr->used = (void *)(((unsigned long)&vr->avail->ring[info->num]
               + info->align - 1) & ~(info->align - 1));

    /* Zero out all relevant field */
    vr->avail->flags = 0;
    vr->avail->idx = 0;

    /* We're running with interrupts off anyways, so don't bother */
    vr->used->flags = VRING_USED_F_NO_NOTIFY;
    vr->used->idx = 0;
    vr->used_idx = 0;
    vr->next_idx = 0;
    vr->cookie = 0;

    debug_print_addr("init vr", vr);
}

static bool vring_notify(VRing *vr)
{
    vr->cookie = virtio_notify(vr->schid, vr->id, vr->cookie);
    return vr->cookie >= 0;
}

static void vring_send_buf(VRing *vr, void *p, int len, int flags)
{
    /* For follow-up chains we need to keep the first entry point */
    if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
        vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
    }

    vr->desc[vr->next_idx].addr = (ulong)p;
    vr->desc[vr->next_idx].len = len;
    vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
    vr->desc[vr->next_idx].next = vr->next_idx;
    vr->desc[vr->next_idx].next++;
    vr->next_idx++;

    /* Chains only have a single ID */
    if (!(flags & VRING_DESC_F_NEXT)) {
        vr->avail->idx++;
    }
}

static u64 get_clock(void)
{
    u64 r;

    asm volatile("stck %0" : "=Q" (r) : : "cc");
    return r;
}

ulong get_second(void)
{
    return (get_clock() >> 12) / 1000000;
}

static int vr_poll(VRing *vr)
{
    if (vr->used->idx == vr->used_idx) {
        vring_notify(vr);
        yield();
        return 0;
    }

    vr->used_idx = vr->used->idx;
    vr->next_idx = 0;
    vr->desc[0].len = 0;
    vr->desc[0].flags = 0;
    return 1; /* vr has been updated */
}

/*
 * Wait for the host to reply.
 *
 * timeout is in seconds if > 0.
 *
 * Returns 0 on success, 1 on timeout.
 */
static int vring_wait_reply(void)
{
    ulong target_second = get_second() + vdev.wait_reply_timeout;

    /* Wait for any queue to be updated by the host */
    do {
        int i, r = 0;

        for (i = 0; i < vdev.nr_vqs; i++) {
            r += vr_poll(&vdev.vrings[i]);
        }
        yield();
        if (r) {
            return 0;
        }
    } while (!vdev.wait_reply_timeout || (get_second() < target_second));

    return 1;
}

int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd)
{
    VRing *vr = &vdev->vrings[vqid];
    int i = 0;

    do {
        vring_send_buf(vr, cmd[i].data, cmd[i].size,
                       cmd[i].flags | (i ? VRING_HIDDEN_IS_CHAIN : 0));
    } while (cmd[i++].flags & VRING_DESC_F_NEXT);

    vring_wait_reply();
    if (drain_irqs(vr->schid)) {
        return -1;
    }
    return 0;
}

/***********************************************
 *               Virtio block                  *
 ***********************************************/

static int virtio_blk_read_many(VDev *vdev,
                                ulong sector, void *load_addr, int sec_num)
{
    VirtioBlkOuthdr out_hdr;
    u8 status;
    VRing *vr = &vdev->vrings[vdev->cmd_vr_idx];

    /* Tell the host we want to read */
    out_hdr.type = VIRTIO_BLK_T_IN;
    out_hdr.ioprio = 99;
    out_hdr.sector = virtio_sector_adjust(sector);

    vring_send_buf(vr, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);

    /* This is where we want to receive data */
    vring_send_buf(vr, load_addr, virtio_get_block_size() * sec_num,
                   VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN |
                   VRING_DESC_F_NEXT);

    /* status field */
    vring_send_buf(vr, &status, sizeof(u8),
                   VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN);

    /* Now we can tell the host to read */
    vring_wait_reply();

    if (drain_irqs(vr->schid)) {
        /* Well, whatever status is supposed to contain... */
        status = 1;
    }
    return status;
}

int virtio_read_many(ulong sector, void *load_addr, int sec_num)
{
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        return virtio_blk_read_many(&vdev, sector, load_addr, sec_num);
    case VIRTIO_ID_SCSI:
        return virtio_scsi_read_many(&vdev, sector, load_addr, sec_num);
    }
    panic("\n! No readable IPL device !\n");
    return -1;
}

unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
                                 ulong subchan_id, void *load_addr)
{
    u8 status;
    int sec = rec_list1;
    int sec_num = ((rec_list2 >> 32) & 0xffff) + 1;
    int sec_len = rec_list2 >> 48;
    ulong addr = (ulong)load_addr;

    if (sec_len != virtio_get_block_size()) {
        return -1;
    }

    sclp_print(".");
    status = virtio_read_many(sec, (void *)addr, sec_num);
    if (status) {
        panic("I/O Error");
    }
    addr += sec_num * virtio_get_block_size();

    return addr;
}

int virtio_read(ulong sector, void *load_addr)
{
    return virtio_read_many(sector, load_addr, 1);
}

/*
 * Other supported value pairs, if any, would need to be added here.
 * Note: head count is always 15.
 */
static inline u8 virtio_eckd_sectors_for_block_size(int size)
{
    switch (size) {
    case 512:
        return 49;
    case 1024:
        return 33;
    case 2048:
        return 21;
    case 4096:
        return 12;
    }
    return 0;
}

VirtioGDN virtio_guessed_disk_nature(void)
{
    return vdev.guessed_disk_nature;
}

void virtio_assume_scsi(void)
{
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        vdev.guessed_disk_nature = VIRTIO_GDN_SCSI;
        vdev.config.blk.blk_size = VIRTIO_SCSI_BLOCK_SIZE;
        vdev.config.blk.physical_block_exp = 0;
        vdev.blk_factor = 1;
        break;
    case VIRTIO_ID_SCSI:
        vdev.scsi_block_size = VIRTIO_SCSI_BLOCK_SIZE;
        break;
    }
}

void virtio_assume_iso9660(void)
{
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        vdev.guessed_disk_nature = VIRTIO_GDN_SCSI;
        vdev.config.blk.blk_size = VIRTIO_ISO_BLOCK_SIZE;
        vdev.config.blk.physical_block_exp = 0;
        vdev.blk_factor = VIRTIO_ISO_BLOCK_SIZE / VIRTIO_SECTOR_SIZE;
        break;
    case VIRTIO_ID_SCSI:
        vdev.scsi_block_size = VIRTIO_ISO_BLOCK_SIZE;
        break;
    }
}

void virtio_assume_eckd(void)
{
    vdev.guessed_disk_nature = VIRTIO_GDN_DASD;
    vdev.blk_factor = 1;
    vdev.config.blk.physical_block_exp = 0;
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        vdev.config.blk.blk_size = 4096;
        break;
    case VIRTIO_ID_SCSI:
        vdev.config.blk.blk_size = vdev.scsi_block_size;
        break;
    }
    vdev.config.blk.geometry.heads = 15;
    vdev.config.blk.geometry.sectors =
        virtio_eckd_sectors_for_block_size(vdev.config.blk.blk_size);
}

bool virtio_disk_is_scsi(void)
{
    if (vdev.guessed_disk_nature == VIRTIO_GDN_SCSI) {
        return true;
    }
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        return (vdev.config.blk.geometry.heads == 255)
            && (vdev.config.blk.geometry.sectors == 63)
            && (virtio_get_block_size()  == VIRTIO_SCSI_BLOCK_SIZE);
    case VIRTIO_ID_SCSI:
        return true;
    }
    return false;
}

bool virtio_disk_is_eckd(void)
{
    const int block_size = virtio_get_block_size();

    if (vdev.guessed_disk_nature == VIRTIO_GDN_DASD) {
        return true;
    }
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        return (vdev.config.blk.geometry.heads == 15)
            && (vdev.config.blk.geometry.sectors ==
                virtio_eckd_sectors_for_block_size(block_size));
    case VIRTIO_ID_SCSI:
        return false;
    }
    return false;
}

bool virtio_ipl_disk_is_valid(void)
{
    return virtio_disk_is_scsi() || virtio_disk_is_eckd();
}

int virtio_get_block_size(void)
{
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        return vdev.config.blk.blk_size << vdev.config.blk.physical_block_exp;
    case VIRTIO_ID_SCSI:
        return vdev.scsi_block_size;
    }
    return 0;
}

uint8_t virtio_get_heads(void)
{
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        return vdev.config.blk.geometry.heads;
    case VIRTIO_ID_SCSI:
        return vdev.guessed_disk_nature == VIRTIO_GDN_DASD
               ? vdev.config.blk.geometry.heads : 255;
    }
    return 0;
}

uint8_t virtio_get_sectors(void)
{
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        return vdev.config.blk.geometry.sectors;
    case VIRTIO_ID_SCSI:
        return vdev.guessed_disk_nature == VIRTIO_GDN_DASD
               ? vdev.config.blk.geometry.sectors : 63;
    }
    return 0;
}

uint64_t virtio_get_blocks(void)
{
    const uint64_t factor = virtio_get_block_size() / VIRTIO_SECTOR_SIZE;
    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        return vdev.config.blk.capacity / factor;
    case VIRTIO_ID_SCSI:
        return vdev.scsi_last_block / factor;
    }
    return 0;
}

static void virtio_setup_ccw(VDev *vdev)
{
    int i, cfg_size = 0;
    unsigned char status = VIRTIO_CONFIG_S_DRIVER_OK;

    IPL_assert(virtio_is_supported(vdev->schid), "PE");
    /* device ID has been established now */

    vdev->config.blk.blk_size = 0; /* mark "illegal" - setup started... */
    vdev->guessed_disk_nature = VIRTIO_GDN_NONE;

    run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0);

    switch (vdev->senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        vdev->nr_vqs = 1;
        vdev->cmd_vr_idx = 0;
        cfg_size = sizeof(vdev->config.blk);
        break;
    case VIRTIO_ID_SCSI:
        vdev->nr_vqs = 3;
        vdev->cmd_vr_idx = VR_REQUEST;
        cfg_size = sizeof(vdev->config.scsi);
        break;
    default:
        panic("Unsupported virtio device\n");
    }
    IPL_assert(run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size) == 0,
               "Could not get block device configuration");

    /*
     * Skipping CCW_CMD_READ_FEAT. We're not doing anything fancy, and
     * we'll just stop dead anyway if anything does not work like we
     * expect it.
     */

    for (i = 0; i < vdev->nr_vqs; i++) {
        VqInfo info = {
            .queue = (unsigned long long) ring_area + (i * VIRTIO_RING_SIZE),
            .align = KVM_S390_VIRTIO_RING_ALIGN,
            .index = i,
            .num = 0,
        };
        VqConfig config = {
            .index = i,
            .num = 0,
        };

        IPL_assert(
            run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config)) == 0,
            "Could not get block device VQ configuration");
        info.num = config.num;
        vring_init(&vdev->vrings[i], &info);
        vdev->vrings[i].schid = vdev->schid;
        IPL_assert(run_ccw(vdev, CCW_CMD_SET_VQ, &info, sizeof(info)) == 0,
                   "Cannot set VQ info");
    }
    IPL_assert(
        run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status)) == 0,
        "Could not write status to host");
}

void virtio_setup_device(SubChannelId schid)
{
    vdev.schid = schid;
    virtio_setup_ccw(&vdev);

    switch (vdev.senseid.cu_model) {
    case VIRTIO_ID_BLOCK:
        sclp_print("Using virtio-blk.\n");
        if (!virtio_ipl_disk_is_valid()) {
            /* make sure all getters but blocksize return 0 for
             * invalid IPL disk
             */
            memset(&vdev.config.blk, 0, sizeof(vdev.config.blk));
            virtio_assume_scsi();
        }
        break;
    case VIRTIO_ID_SCSI:
        IPL_assert(vdev.config.scsi.sense_size == VIRTIO_SCSI_SENSE_SIZE,
            "Config: sense size mismatch");
        IPL_assert(vdev.config.scsi.cdb_size == VIRTIO_SCSI_CDB_SIZE,
            "Config: CDB size mismatch");

        sclp_print("Using virtio-scsi.\n");
        virtio_scsi_setup(&vdev);
        break;
    default:
        panic("\n! No IPL device available !\n");
    }
}

bool virtio_is_supported(SubChannelId schid)
{
    vdev.schid = schid;
    memset(&vdev.senseid, 0, sizeof(vdev.senseid));
    /* run sense id command */
    if (run_ccw(&vdev, CCW_CMD_SENSE_ID, &vdev.senseid, sizeof(vdev.senseid))) {
        return false;
    }
    if (vdev.senseid.cu_type == 0x3832) {
        switch (vdev.senseid.cu_model) {
        case VIRTIO_ID_BLOCK:
        case VIRTIO_ID_SCSI:
            return true;
        }
    }
    return false;
}

int enable_mss_facility(void)
{
    int ret;
    ChscAreaSda *sda_area = (ChscAreaSda *) chsc_page;

    memset(sda_area, 0, PAGE_SIZE);
    sda_area->request.length = 0x0400;
    sda_area->request.code = 0x0031;
    sda_area->operation_code = 0x2;

    ret = chsc(sda_area);
    if ((ret == 0) && (sda_area->response.code == 0x0001)) {
        return 0;
    }
    return -EIO;
}