summaryrefslogtreecommitdiff
path: root/pc-bios/s390-ccw/virtio.c
blob: 57ff1b07ee9229f597aec23fcd1c1ae2ebdb5f6b (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
/*
 * 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"

static struct vring block;

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

static long kvm_hypercall(unsigned long nr, unsigned long param1,
                          unsigned long param2)
{
    register ulong r_nr asm("1") = nr;
    register ulong r_param1 asm("2") = param1;
    register ulong r_param2 asm("3") = param2;
    register long retval asm("2");

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

    return retval;
}

static void virtio_notify(struct subchannel_id schid)
{
    kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid, 0);
}

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

static int drain_irqs(struct subchannel_id schid)
{
    struct 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(struct subchannel_id schid, int cmd, void *ptr, int len)
{
    struct ccw1 ccw = {};
    struct cmd_orb orb = {};
    struct schib schib;
    int r;

    /* start command processing */
    stsch_err(schid, &schib);
    schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
    msch(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(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(schid);
    }
    return r;
}

static void virtio_set_status(struct subchannel_id schid,
                              unsigned long dev_addr)
{
    unsigned char status = dev_addr;
    if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
        virtio_panic("Could not write status to host!\n");
    }
}

static void virtio_reset(struct subchannel_id schid)
{
    run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
}

static void vring_init(struct vring *vr, unsigned int num, void *p,
                       unsigned long align)
{
    debug_print_addr("init p", p);
    vr->num = num;
    vr->desc = p;
    vr->avail = p + num*sizeof(struct vring_desc);
    vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
                & ~(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;

    debug_print_addr("init vr", vr);
}

static void vring_notify(struct subchannel_id schid)
{
    virtio_notify(schid);
}

static void vring_send_buf(struct 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;
}

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

/*
 * Wait for the host to reply.
 *
 * timeout is in seconds if > 0.
 *
 * Returns 0 on success, 1 on timeout.
 */
static int vring_wait_reply(struct vring *vr, int timeout)
{
    ulong target_second = get_second() + timeout;
    struct subchannel_id schid = vr->schid;
    int r = 0;

    /* Wait until the used index has moved. */
    while (vr->used->idx == vr->used_idx) {
        vring_notify(schid);
        if (timeout && (get_second() >= target_second)) {
            r = 1;
            break;
        }
        yield();
    }

    vr->used_idx = vr->used->idx;
    vr->next_idx = 0;
    vr->desc[0].len = 0;
    vr->desc[0].flags = 0;

    return r;
}

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

int virtio_read_many(ulong sector, void *load_addr, int sec_num)
{
    struct virtio_blk_outhdr out_hdr;
    u8 status;
    int r;

    /* 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(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);

    /* This is where we want to receive data */
    vring_send_buf(&block, 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(&block, &status, sizeof(u8), VRING_DESC_F_WRITE |
                   VRING_HIDDEN_IS_CHAIN);

    /* Now we can tell the host to read */
    vring_wait_reply(&block, 0);

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

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) {
        virtio_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);
}

static VirtioBlkConfig blk_cfg = {};
static bool guessed_disk_nature;

bool virtio_guessed_disk_nature(void)
{
    return guessed_disk_nature;
}

void virtio_assume_scsi(void)
{
    guessed_disk_nature = true;
    blk_cfg.blk_size = 512;
    blk_cfg.physical_block_exp = 0;
}

void virtio_assume_eckd(void)
{
    guessed_disk_nature = true;
    blk_cfg.blk_size = 4096;
    blk_cfg.physical_block_exp = 0;

    /* this must be here to calculate code segment position */
    blk_cfg.geometry.heads = 15;
    blk_cfg.geometry.sectors = 12;
}

bool virtio_disk_is_scsi(void)
{
    if (guessed_disk_nature) {
        return (virtio_get_block_size()  == 512);
    }
    return (blk_cfg.geometry.heads == 255)
        && (blk_cfg.geometry.sectors == 63)
        && (virtio_get_block_size()  == 512);
}

/*
 * 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;
}

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

    if (guessed_disk_nature) {
        return (block_size  == 4096);
    }
    return (blk_cfg.geometry.heads == 15)
        && (blk_cfg.geometry.sectors ==
            virtio_eckd_sectors_for_block_size(block_size));
}

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

int virtio_get_block_size(void)
{
    return blk_cfg.blk_size << blk_cfg.physical_block_exp;
}

uint8_t virtio_get_heads(void)
{
    return blk_cfg.geometry.heads;
}

uint8_t virtio_get_sectors(void)
{
    return blk_cfg.geometry.sectors;
}

uint64_t virtio_get_blocks(void)
{
    return blk_cfg.capacity /
           (virtio_get_block_size() / VIRTIO_SECTOR_SIZE);
}

void virtio_setup_block(struct subchannel_id schid)
{
    struct vq_info_block info;
    struct vq_config_block config = {};

    blk_cfg.blk_size = 0; /* mark "illegal" - setup started... */
    guessed_disk_nature = false;

    virtio_reset(schid);

    /*
     * 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.
     */

    config.index = 0;
    if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
        virtio_panic("Could not get block device VQ configuration\n");
    }
    if (run_ccw(schid, CCW_CMD_READ_CONF, &blk_cfg, sizeof(blk_cfg))) {
        virtio_panic("Could not get block device configuration\n");
    }
    vring_init(&block, config.num, ring_area,
               KVM_S390_VIRTIO_RING_ALIGN);

    info.queue = (unsigned long long) ring_area;
    info.align = KVM_S390_VIRTIO_RING_ALIGN;
    info.index = 0;
    info.num = config.num;
    block.schid = schid;

    if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
        virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
    }

    if (!virtio_ipl_disk_is_valid()) {
        /* make sure all getters but blocksize return 0 for invalid IPL disk */
        memset(&blk_cfg, 0, sizeof(blk_cfg));
        virtio_assume_scsi();
    }
}

bool virtio_is_blk(struct subchannel_id schid)
{
    int r;
    struct senseid senseid = {};

    /* run sense id command */
    r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
    if (r) {
        return false;
    }
    if ((senseid.cu_type != 0x3832) || (senseid.cu_model != VIRTIO_ID_BLOCK)) {
        return false;
    }

    return true;
}

int enable_mss_facility(void)
{
    int ret;
    struct chsc_area_sda *sda_area = (struct chsc_area_sda *) 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;
}