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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * channel program interfaces
4 *
5 * Copyright IBM Corp. 2017
6 *
7 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
8 * Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
9 */
10
11#include <linux/ratelimit.h>
12#include <linux/mm.h>
13#include <linux/slab.h>
14#include <linux/highmem.h>
15#include <linux/iommu.h>
16#include <linux/vfio.h>
17#include <asm/idals.h>
18
19#include "vfio_ccw_cp.h"
20#include "vfio_ccw_private.h"
21
22struct page_array {
23 /* Array that stores pages need to pin. */
24 dma_addr_t *pa_iova;
25 /* Array that receives the pinned pages. */
26 struct page **pa_page;
27 /* Number of pages pinned from @pa_iova. */
28 int pa_nr;
29};
30
31struct ccwchain {
32 struct list_head next;
33 struct ccw1 *ch_ccw;
34 /* Guest physical address of the current chain. */
35 u64 ch_iova;
36 /* Count of the valid ccws in chain. */
37 int ch_len;
38 /* Pinned PAGEs for the original data. */
39 struct page_array *ch_pa;
40};
41
42/*
43 * page_array_alloc() - alloc memory for page array
44 * @pa: page_array on which to perform the operation
45 * @len: number of pages that should be pinned from @iova
46 *
47 * Attempt to allocate memory for page array.
48 *
49 * Usage of page_array:
50 * We expect (pa_nr == 0) and (pa_iova == NULL), any field in
51 * this structure will be filled in by this function.
52 *
53 * Returns:
54 * 0 if page array is allocated
55 * -EINVAL if pa->pa_nr is not initially zero, or pa->pa_iova is not NULL
56 * -ENOMEM if alloc failed
57 */
58static int page_array_alloc(struct page_array *pa, unsigned int len)
59{
60 if (pa->pa_nr || pa->pa_iova)
61 return -EINVAL;
62
63 if (len == 0)
64 return -EINVAL;
65
66 pa->pa_nr = len;
67
68 pa->pa_iova = kcalloc(len, sizeof(*pa->pa_iova), GFP_KERNEL);
69 if (!pa->pa_iova)
70 return -ENOMEM;
71
72 pa->pa_page = kcalloc(len, sizeof(*pa->pa_page), GFP_KERNEL);
73 if (!pa->pa_page) {
74 kfree(pa->pa_iova);
75 return -ENOMEM;
76 }
77
78 return 0;
79}
80
81/*
82 * page_array_unpin() - Unpin user pages in memory
83 * @pa: page_array on which to perform the operation
84 * @vdev: the vfio device to perform the operation
85 * @pa_nr: number of user pages to unpin
86 * @unaligned: were pages unaligned on the pin request
87 *
88 * Only unpin if any pages were pinned to begin with, i.e. pa_nr > 0,
89 * otherwise only clear pa->pa_nr
90 */
91static void page_array_unpin(struct page_array *pa,
92 struct vfio_device *vdev, int pa_nr, bool unaligned)
93{
94 int unpinned = 0, npage = 1;
95
96 while (unpinned < pa_nr) {
97 dma_addr_t *first = &pa->pa_iova[unpinned];
98 dma_addr_t *last = &first[npage];
99
100 if (unpinned + npage < pa_nr &&
101 *first + npage * PAGE_SIZE == *last &&
102 !unaligned) {
103 npage++;
104 continue;
105 }
106
107 vfio_unpin_pages(vdev, *first, npage);
108 unpinned += npage;
109 npage = 1;
110 }
111
112 pa->pa_nr = 0;
113}
114
115/*
116 * page_array_pin() - Pin user pages in memory
117 * @pa: page_array on which to perform the operation
118 * @vdev: the vfio device to perform pin operations
119 * @unaligned: are pages aligned to 4K boundary?
120 *
121 * Returns number of pages pinned upon success.
122 * If the pin request partially succeeds, or fails completely,
123 * all pages are left unpinned and a negative error value is returned.
124 *
125 * Requests to pin "aligned" pages can be coalesced into a single
126 * vfio_pin_pages request for the sake of efficiency, based on the
127 * expectation of 4K page requests. Unaligned requests are probably
128 * dealing with 2K "pages", and cannot be coalesced without
129 * reworking this logic to incorporate that math.
130 */
131static int page_array_pin(struct page_array *pa, struct vfio_device *vdev, bool unaligned)
132{
133 int pinned = 0, npage = 1;
134 int ret = 0;
135
136 while (pinned < pa->pa_nr) {
137 dma_addr_t *first = &pa->pa_iova[pinned];
138 dma_addr_t *last = &first[npage];
139
140 if (pinned + npage < pa->pa_nr &&
141 *first + npage * PAGE_SIZE == *last &&
142 !unaligned) {
143 npage++;
144 continue;
145 }
146
147 ret = vfio_pin_pages(vdev, *first, npage,
148 IOMMU_READ | IOMMU_WRITE,
149 &pa->pa_page[pinned]);
150 if (ret < 0) {
151 goto err_out;
152 } else if (ret > 0 && ret != npage) {
153 pinned += ret;
154 ret = -EINVAL;
155 goto err_out;
156 }
157 pinned += npage;
158 npage = 1;
159 }
160
161 return ret;
162
163err_out:
164 page_array_unpin(pa, vdev, pinned, unaligned);
165 return ret;
166}
167
168/* Unpin the pages before releasing the memory. */
169static void page_array_unpin_free(struct page_array *pa, struct vfio_device *vdev, bool unaligned)
170{
171 page_array_unpin(pa, vdev, pa->pa_nr, unaligned);
172 kfree(pa->pa_page);
173 kfree(pa->pa_iova);
174}
175
176static bool page_array_iova_pinned(struct page_array *pa, u64 iova, u64 length)
177{
178 u64 iova_pfn_start = iova >> PAGE_SHIFT;
179 u64 iova_pfn_end = (iova + length - 1) >> PAGE_SHIFT;
180 u64 pfn;
181 int i;
182
183 for (i = 0; i < pa->pa_nr; i++) {
184 pfn = pa->pa_iova[i] >> PAGE_SHIFT;
185 if (pfn >= iova_pfn_start && pfn <= iova_pfn_end)
186 return true;
187 }
188
189 return false;
190}
191/* Create the list of IDAL words for a page_array. */
192static inline void page_array_idal_create_words(struct page_array *pa,
193 dma64_t *idaws)
194{
195 int i;
196
197 /*
198 * Idal words (execept the first one) rely on the memory being 4k
199 * aligned. If a user virtual address is 4K aligned, then it's
200 * corresponding kernel physical address will also be 4K aligned. Thus
201 * there will be no problem here to simply use the phys to create an
202 * idaw.
203 */
204
205 for (i = 0; i < pa->pa_nr; i++) {
206 idaws[i] = virt_to_dma64(page_to_virt(pa->pa_page[i]));
207
208 /* Incorporate any offset from each starting address */
209 idaws[i] = dma64_add(idaws[i], pa->pa_iova[i] & ~PAGE_MASK);
210 }
211}
212
213static void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len)
214{
215 struct ccw0 ccw0;
216 struct ccw1 *pccw1 = source;
217 int i;
218
219 for (i = 0; i < len; i++) {
220 ccw0 = *(struct ccw0 *)pccw1;
221 if ((pccw1->cmd_code & 0x0f) == CCW_CMD_TIC) {
222 pccw1->cmd_code = CCW_CMD_TIC;
223 pccw1->flags = 0;
224 pccw1->count = 0;
225 } else {
226 pccw1->cmd_code = ccw0.cmd_code;
227 pccw1->flags = ccw0.flags;
228 pccw1->count = ccw0.count;
229 }
230 pccw1->cda = u32_to_dma32(ccw0.cda);
231 pccw1++;
232 }
233}
234
235#define idal_is_2k(_cp) (!(_cp)->orb.cmd.c64 || (_cp)->orb.cmd.i2k)
236
237/*
238 * Helpers to operate ccwchain.
239 */
240#define ccw_is_read(_ccw) (((_ccw)->cmd_code & 0x03) == 0x02)
241#define ccw_is_read_backward(_ccw) (((_ccw)->cmd_code & 0x0F) == 0x0C)
242#define ccw_is_sense(_ccw) (((_ccw)->cmd_code & 0x0F) == CCW_CMD_BASIC_SENSE)
243
244#define ccw_is_noop(_ccw) ((_ccw)->cmd_code == CCW_CMD_NOOP)
245
246#define ccw_is_tic(_ccw) ((_ccw)->cmd_code == CCW_CMD_TIC)
247
248#define ccw_is_idal(_ccw) ((_ccw)->flags & CCW_FLAG_IDA)
249#define ccw_is_skip(_ccw) ((_ccw)->flags & CCW_FLAG_SKIP)
250
251#define ccw_is_chain(_ccw) ((_ccw)->flags & (CCW_FLAG_CC | CCW_FLAG_DC))
252
253/*
254 * ccw_does_data_transfer()
255 *
256 * Determine whether a CCW will move any data, such that the guest pages
257 * would need to be pinned before performing the I/O.
258 *
259 * Returns 1 if yes, 0 if no.
260 */
261static inline int ccw_does_data_transfer(struct ccw1 *ccw)
262{
263 /* If the count field is zero, then no data will be transferred */
264 if (ccw->count == 0)
265 return 0;
266
267 /* If the command is a NOP, then no data will be transferred */
268 if (ccw_is_noop(ccw))
269 return 0;
270
271 /* If the skip flag is off, then data will be transferred */
272 if (!ccw_is_skip(ccw))
273 return 1;
274
275 /*
276 * If the skip flag is on, it is only meaningful if the command
277 * code is a read, read backward, sense, or sense ID. In those
278 * cases, no data will be transferred.
279 */
280 if (ccw_is_read(ccw) || ccw_is_read_backward(ccw))
281 return 0;
282
283 if (ccw_is_sense(ccw))
284 return 0;
285
286 /* The skip flag is on, but it is ignored for this command code. */
287 return 1;
288}
289
290/*
291 * is_cpa_within_range()
292 *
293 * @cpa: channel program address being questioned
294 * @head: address of the beginning of a CCW chain
295 * @len: number of CCWs within the chain
296 *
297 * Determine whether the address of a CCW (whether a new chain,
298 * or the target of a TIC) falls within a range (including the end points).
299 *
300 * Returns 1 if yes, 0 if no.
301 */
302static inline int is_cpa_within_range(dma32_t cpa, u32 head, int len)
303{
304 u32 tail = head + (len - 1) * sizeof(struct ccw1);
305 u32 gcpa = dma32_to_u32(cpa);
306
307 return head <= gcpa && gcpa <= tail;
308}
309
310static inline int is_tic_within_range(struct ccw1 *ccw, u32 head, int len)
311{
312 if (!ccw_is_tic(ccw))
313 return 0;
314
315 return is_cpa_within_range(ccw->cda, head, len);
316}
317
318static struct ccwchain *ccwchain_alloc(struct channel_program *cp, int len)
319{
320 struct ccwchain *chain;
321
322 chain = kzalloc(sizeof(*chain), GFP_KERNEL);
323 if (!chain)
324 return NULL;
325
326 chain->ch_ccw = kcalloc(len, sizeof(*chain->ch_ccw), GFP_DMA | GFP_KERNEL);
327 if (!chain->ch_ccw)
328 goto out_err;
329
330 chain->ch_pa = kcalloc(len, sizeof(*chain->ch_pa), GFP_KERNEL);
331 if (!chain->ch_pa)
332 goto out_err;
333
334 list_add_tail(&chain->next, &cp->ccwchain_list);
335
336 return chain;
337
338out_err:
339 kfree(chain->ch_ccw);
340 kfree(chain);
341 return NULL;
342}
343
344static void ccwchain_free(struct ccwchain *chain)
345{
346 list_del(&chain->next);
347 kfree(chain->ch_pa);
348 kfree(chain->ch_ccw);
349 kfree(chain);
350}
351
352/* Free resource for a ccw that allocated memory for its cda. */
353static void ccwchain_cda_free(struct ccwchain *chain, int idx)
354{
355 struct ccw1 *ccw = &chain->ch_ccw[idx];
356
357 if (ccw_is_tic(ccw))
358 return;
359
360 kfree(dma32_to_virt(ccw->cda));
361}
362
363/**
364 * ccwchain_calc_length - calculate the length of the ccw chain.
365 * @iova: guest physical address of the target ccw chain
366 * @cp: channel_program on which to perform the operation
367 *
368 * This is the chain length not considering any TICs.
369 * You need to do a new round for each TIC target.
370 *
371 * The program is also validated for absence of not yet supported
372 * indirect data addressing scenarios.
373 *
374 * Returns: the length of the ccw chain or -errno.
375 */
376static int ccwchain_calc_length(u64 iova, struct channel_program *cp)
377{
378 struct ccw1 *ccw = cp->guest_cp;
379 int cnt = 0;
380
381 do {
382 cnt++;
383
384 /*
385 * We want to keep counting if the current CCW has the
386 * command-chaining flag enabled, or if it is a TIC CCW
387 * that loops back into the current chain. The latter
388 * is used for device orientation, where the CCW PRIOR to
389 * the TIC can either jump to the TIC or a CCW immediately
390 * after the TIC, depending on the results of its operation.
391 */
392 if (!ccw_is_chain(ccw) && !is_tic_within_range(ccw, iova, cnt))
393 break;
394
395 ccw++;
396 } while (cnt < CCWCHAIN_LEN_MAX + 1);
397
398 if (cnt == CCWCHAIN_LEN_MAX + 1)
399 cnt = -EINVAL;
400
401 return cnt;
402}
403
404static int tic_target_chain_exists(struct ccw1 *tic, struct channel_program *cp)
405{
406 struct ccwchain *chain;
407 u32 ccw_head;
408
409 list_for_each_entry(chain, &cp->ccwchain_list, next) {
410 ccw_head = chain->ch_iova;
411 if (is_cpa_within_range(tic->cda, ccw_head, chain->ch_len))
412 return 1;
413 }
414
415 return 0;
416}
417
418static int ccwchain_loop_tic(struct ccwchain *chain,
419 struct channel_program *cp);
420
421static int ccwchain_handle_ccw(dma32_t cda, struct channel_program *cp)
422{
423 struct vfio_device *vdev =
424 &container_of(cp, struct vfio_ccw_private, cp)->vdev;
425 struct ccwchain *chain;
426 int len, ret;
427 u32 gcda;
428
429 gcda = dma32_to_u32(cda);
430 /* Copy 2K (the most we support today) of possible CCWs */
431 ret = vfio_dma_rw(vdev, gcda, cp->guest_cp, CCWCHAIN_LEN_MAX * sizeof(struct ccw1), false);
432 if (ret)
433 return ret;
434
435 /* Convert any Format-0 CCWs to Format-1 */
436 if (!cp->orb.cmd.fmt)
437 convert_ccw0_to_ccw1(cp->guest_cp, CCWCHAIN_LEN_MAX);
438
439 /* Count the CCWs in the current chain */
440 len = ccwchain_calc_length(gcda, cp);
441 if (len < 0)
442 return len;
443
444 /* Need alloc a new chain for this one. */
445 chain = ccwchain_alloc(cp, len);
446 if (!chain)
447 return -ENOMEM;
448
449 chain->ch_len = len;
450 chain->ch_iova = gcda;
451
452 /* Copy the actual CCWs into the new chain */
453 memcpy(chain->ch_ccw, cp->guest_cp, len * sizeof(struct ccw1));
454
455 /* Loop for tics on this new chain. */
456 ret = ccwchain_loop_tic(chain, cp);
457
458 if (ret)
459 ccwchain_free(chain);
460
461 return ret;
462}
463
464/* Loop for TICs. */
465static int ccwchain_loop_tic(struct ccwchain *chain, struct channel_program *cp)
466{
467 struct ccw1 *tic;
468 int i, ret;
469
470 for (i = 0; i < chain->ch_len; i++) {
471 tic = &chain->ch_ccw[i];
472
473 if (!ccw_is_tic(tic))
474 continue;
475
476 /* May transfer to an existing chain. */
477 if (tic_target_chain_exists(tic, cp))
478 continue;
479
480 /* Build a ccwchain for the next segment */
481 ret = ccwchain_handle_ccw(tic->cda, cp);
482 if (ret)
483 return ret;
484 }
485
486 return 0;
487}
488
489static int ccwchain_fetch_tic(struct ccw1 *ccw,
490 struct channel_program *cp)
491{
492 struct ccwchain *iter;
493 u32 cda, ccw_head;
494
495 list_for_each_entry(iter, &cp->ccwchain_list, next) {
496 ccw_head = iter->ch_iova;
497 if (is_cpa_within_range(ccw->cda, ccw_head, iter->ch_len)) {
498 cda = (u64)iter->ch_ccw + dma32_to_u32(ccw->cda) - ccw_head;
499 ccw->cda = u32_to_dma32(cda);
500 return 0;
501 }
502 }
503
504 return -EFAULT;
505}
506
507static dma64_t *get_guest_idal(struct ccw1 *ccw, struct channel_program *cp, int idaw_nr)
508{
509 struct vfio_device *vdev =
510 &container_of(cp, struct vfio_ccw_private, cp)->vdev;
511 dma64_t *idaws;
512 dma32_t *idaws_f1;
513 int idal_len = idaw_nr * sizeof(*idaws);
514 int idaw_size = idal_is_2k(cp) ? PAGE_SIZE / 2 : PAGE_SIZE;
515 int idaw_mask = ~(idaw_size - 1);
516 int i, ret;
517
518 idaws = kcalloc(idaw_nr, sizeof(*idaws), GFP_DMA | GFP_KERNEL);
519 if (!idaws)
520 return ERR_PTR(-ENOMEM);
521
522 if (ccw_is_idal(ccw)) {
523 /* Copy IDAL from guest */
524 ret = vfio_dma_rw(vdev, dma32_to_u32(ccw->cda), idaws, idal_len, false);
525 if (ret) {
526 kfree(idaws);
527 return ERR_PTR(ret);
528 }
529 } else {
530 /* Fabricate an IDAL based off CCW data address */
531 if (cp->orb.cmd.c64) {
532 idaws[0] = u64_to_dma64(dma32_to_u32(ccw->cda));
533 for (i = 1; i < idaw_nr; i++) {
534 idaws[i] = dma64_add(idaws[i - 1], idaw_size);
535 idaws[i] = dma64_and(idaws[i], idaw_mask);
536 }
537 } else {
538 idaws_f1 = (dma32_t *)idaws;
539 idaws_f1[0] = ccw->cda;
540 for (i = 1; i < idaw_nr; i++) {
541 idaws_f1[i] = dma32_add(idaws_f1[i - 1], idaw_size);
542 idaws_f1[i] = dma32_and(idaws_f1[i], idaw_mask);
543 }
544 }
545 }
546
547 return idaws;
548}
549
550/*
551 * ccw_count_idaws() - Calculate the number of IDAWs needed to transfer
552 * a specified amount of data
553 *
554 * @ccw: The Channel Command Word being translated
555 * @cp: Channel Program being processed
556 *
557 * The ORB is examined, since it specifies what IDAWs could actually be
558 * used by any CCW in the channel program, regardless of whether or not
559 * the CCW actually does. An ORB that does not specify Format-2-IDAW
560 * Control could still contain a CCW with an IDAL, which would be
561 * Format-1 and thus only move 2K with each IDAW. Thus all CCWs within
562 * the channel program must follow the same size requirements.
563 */
564static int ccw_count_idaws(struct ccw1 *ccw,
565 struct channel_program *cp)
566{
567 struct vfio_device *vdev =
568 &container_of(cp, struct vfio_ccw_private, cp)->vdev;
569 u64 iova;
570 int size = cp->orb.cmd.c64 ? sizeof(u64) : sizeof(u32);
571 int ret;
572 int bytes = 1;
573
574 if (ccw->count)
575 bytes = ccw->count;
576
577 if (ccw_is_idal(ccw)) {
578 /* Read first IDAW to check its starting address. */
579 /* All subsequent IDAWs will be 2K- or 4K-aligned. */
580 ret = vfio_dma_rw(vdev, dma32_to_u32(ccw->cda), &iova, size, false);
581 if (ret)
582 return ret;
583
584 /*
585 * Format-1 IDAWs only occupy the first 32 bits,
586 * and bit 0 is always off.
587 */
588 if (!cp->orb.cmd.c64)
589 iova = iova >> 32;
590 } else {
591 iova = dma32_to_u32(ccw->cda);
592 }
593
594 /* Format-1 IDAWs operate on 2K each */
595 if (!cp->orb.cmd.c64)
596 return idal_2k_nr_words((void *)iova, bytes);
597
598 /* Using the 2K variant of Format-2 IDAWs? */
599 if (cp->orb.cmd.i2k)
600 return idal_2k_nr_words((void *)iova, bytes);
601
602 /* The 'usual' case is 4K Format-2 IDAWs */
603 return idal_nr_words((void *)iova, bytes);
604}
605
606static int ccwchain_fetch_ccw(struct ccw1 *ccw,
607 struct page_array *pa,
608 struct channel_program *cp)
609{
610 struct vfio_device *vdev =
611 &container_of(cp, struct vfio_ccw_private, cp)->vdev;
612 dma64_t *idaws;
613 dma32_t *idaws_f1;
614 int ret;
615 int idaw_nr;
616 int i;
617
618 /* Calculate size of IDAL */
619 idaw_nr = ccw_count_idaws(ccw, cp);
620 if (idaw_nr < 0)
621 return idaw_nr;
622
623 /* Allocate an IDAL from host storage */
624 idaws = get_guest_idal(ccw, cp, idaw_nr);
625 if (IS_ERR(idaws)) {
626 ret = PTR_ERR(idaws);
627 goto out_init;
628 }
629
630 /*
631 * Allocate an array of pages to pin/translate.
632 * The number of pages is actually the count of the idaws
633 * required for the data transfer, since we only only support
634 * 4K IDAWs today.
635 */
636 ret = page_array_alloc(pa, idaw_nr);
637 if (ret < 0)
638 goto out_free_idaws;
639
640 /*
641 * Copy guest IDAWs into page_array, in case the memory they
642 * occupy is not contiguous.
643 */
644 idaws_f1 = (dma32_t *)idaws;
645 for (i = 0; i < idaw_nr; i++) {
646 if (cp->orb.cmd.c64)
647 pa->pa_iova[i] = dma64_to_u64(idaws[i]);
648 else
649 pa->pa_iova[i] = dma32_to_u32(idaws_f1[i]);
650 }
651
652 if (ccw_does_data_transfer(ccw)) {
653 ret = page_array_pin(pa, vdev, idal_is_2k(cp));
654 if (ret < 0)
655 goto out_unpin;
656 } else {
657 pa->pa_nr = 0;
658 }
659
660 ccw->cda = virt_to_dma32(idaws);
661 ccw->flags |= CCW_FLAG_IDA;
662
663 /* Populate the IDAL with pinned/translated addresses from page */
664 page_array_idal_create_words(pa, idaws);
665
666 return 0;
667
668out_unpin:
669 page_array_unpin_free(pa, vdev, idal_is_2k(cp));
670out_free_idaws:
671 kfree(idaws);
672out_init:
673 ccw->cda = 0;
674 return ret;
675}
676
677/*
678 * Fetch one ccw.
679 * To reduce memory copy, we'll pin the cda page in memory,
680 * and to get rid of the cda 2G limitation of ccw1, we'll translate
681 * direct ccws to idal ccws.
682 */
683static int ccwchain_fetch_one(struct ccw1 *ccw,
684 struct page_array *pa,
685 struct channel_program *cp)
686
687{
688 if (ccw_is_tic(ccw))
689 return ccwchain_fetch_tic(ccw, cp);
690
691 return ccwchain_fetch_ccw(ccw, pa, cp);
692}
693
694/**
695 * cp_init() - allocate ccwchains for a channel program.
696 * @cp: channel_program on which to perform the operation
697 * @orb: control block for the channel program from the guest
698 *
699 * This creates one or more ccwchain(s), and copies the raw data of
700 * the target channel program from @orb->cmd.iova to the new ccwchain(s).
701 *
702 * Limitations:
703 * 1. Supports idal(c64) ccw chaining.
704 * 2. Supports 4k idaw.
705 *
706 * Returns:
707 * %0 on success and a negative error value on failure.
708 */
709int cp_init(struct channel_program *cp, union orb *orb)
710{
711 struct vfio_device *vdev =
712 &container_of(cp, struct vfio_ccw_private, cp)->vdev;
713 /* custom ratelimit used to avoid flood during guest IPL */
714 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 1);
715 int ret;
716
717 /* this is an error in the caller */
718 if (cp->initialized)
719 return -EBUSY;
720
721 /*
722 * We only support prefetching the channel program. We assume all channel
723 * programs executed by supported guests likewise support prefetching.
724 * Executing a channel program that does not specify prefetching will
725 * typically not cause an error, but a warning is issued to help identify
726 * the problem if something does break.
727 */
728 if (!orb->cmd.pfch && __ratelimit(&ratelimit_state))
729 dev_warn(
730 vdev->dev,
731 "Prefetching channel program even though prefetch not specified in ORB");
732
733 INIT_LIST_HEAD(&cp->ccwchain_list);
734 memcpy(&cp->orb, orb, sizeof(*orb));
735
736 /* Build a ccwchain for the first CCW segment */
737 ret = ccwchain_handle_ccw(orb->cmd.cpa, cp);
738
739 if (!ret)
740 cp->initialized = true;
741
742 return ret;
743}
744
745
746/**
747 * cp_free() - free resources for channel program.
748 * @cp: channel_program on which to perform the operation
749 *
750 * This unpins the memory pages and frees the memory space occupied by
751 * @cp, which must have been returned by a previous call to cp_init().
752 * Otherwise, undefined behavior occurs.
753 */
754void cp_free(struct channel_program *cp)
755{
756 struct vfio_device *vdev =
757 &container_of(cp, struct vfio_ccw_private, cp)->vdev;
758 struct ccwchain *chain, *temp;
759 int i;
760
761 if (!cp->initialized)
762 return;
763
764 cp->initialized = false;
765 list_for_each_entry_safe(chain, temp, &cp->ccwchain_list, next) {
766 for (i = 0; i < chain->ch_len; i++) {
767 page_array_unpin_free(&chain->ch_pa[i], vdev, idal_is_2k(cp));
768 ccwchain_cda_free(chain, i);
769 }
770 ccwchain_free(chain);
771 }
772}
773
774/**
775 * cp_prefetch() - translate a guest physical address channel program to
776 * a real-device runnable channel program.
777 * @cp: channel_program on which to perform the operation
778 *
779 * This function translates the guest-physical-address channel program
780 * and stores the result to ccwchain list. @cp must have been
781 * initialized by a previous call with cp_init(). Otherwise, undefined
782 * behavior occurs.
783 * For each chain composing the channel program:
784 * - On entry ch_len holds the count of CCWs to be translated.
785 * - On exit ch_len is adjusted to the count of successfully translated CCWs.
786 * This allows cp_free to find in ch_len the count of CCWs to free in a chain.
787 *
788 * The S/390 CCW Translation APIS (prefixed by 'cp_') are introduced
789 * as helpers to do ccw chain translation inside the kernel. Basically
790 * they accept a channel program issued by a virtual machine, and
791 * translate the channel program to a real-device runnable channel
792 * program.
793 *
794 * These APIs will copy the ccws into kernel-space buffers, and update
795 * the guest physical addresses with their corresponding host physical
796 * addresses. Then channel I/O device drivers could issue the
797 * translated channel program to real devices to perform an I/O
798 * operation.
799 *
800 * These interfaces are designed to support translation only for
801 * channel programs, which are generated and formatted by a
802 * guest. Thus this will make it possible for things like VFIO to
803 * leverage the interfaces to passthrough a channel I/O mediated
804 * device in QEMU.
805 *
806 * We support direct ccw chaining by translating them to idal ccws.
807 *
808 * Returns:
809 * %0 on success and a negative error value on failure.
810 */
811int cp_prefetch(struct channel_program *cp)
812{
813 struct ccwchain *chain;
814 struct ccw1 *ccw;
815 struct page_array *pa;
816 int len, idx, ret;
817
818 /* this is an error in the caller */
819 if (!cp->initialized)
820 return -EINVAL;
821
822 list_for_each_entry(chain, &cp->ccwchain_list, next) {
823 len = chain->ch_len;
824 for (idx = 0; idx < len; idx++) {
825 ccw = &chain->ch_ccw[idx];
826 pa = &chain->ch_pa[idx];
827
828 ret = ccwchain_fetch_one(ccw, pa, cp);
829 if (ret)
830 goto out_err;
831 }
832 }
833
834 return 0;
835out_err:
836 /* Only cleanup the chain elements that were actually translated. */
837 chain->ch_len = idx;
838 list_for_each_entry_continue(chain, &cp->ccwchain_list, next) {
839 chain->ch_len = 0;
840 }
841 return ret;
842}
843
844/**
845 * cp_get_orb() - get the orb of the channel program
846 * @cp: channel_program on which to perform the operation
847 * @sch: subchannel the operation will be performed against
848 *
849 * This function returns the address of the updated orb of the channel
850 * program. Channel I/O device drivers could use this orb to issue a
851 * ssch.
852 */
853union orb *cp_get_orb(struct channel_program *cp, struct subchannel *sch)
854{
855 union orb *orb;
856 struct ccwchain *chain;
857 struct ccw1 *cpa;
858
859 /* this is an error in the caller */
860 if (!cp->initialized)
861 return NULL;
862
863 orb = &cp->orb;
864
865 orb->cmd.intparm = (u32)virt_to_phys(sch);
866 orb->cmd.fmt = 1;
867
868 /*
869 * Everything built by vfio-ccw is a Format-2 IDAL.
870 * If the input was a Format-1 IDAL, indicate that
871 * 2K Format-2 IDAWs were created here.
872 */
873 if (!orb->cmd.c64)
874 orb->cmd.i2k = 1;
875 orb->cmd.c64 = 1;
876
877 if (orb->cmd.lpm == 0)
878 orb->cmd.lpm = sch->lpm;
879
880 chain = list_first_entry(&cp->ccwchain_list, struct ccwchain, next);
881 cpa = chain->ch_ccw;
882 orb->cmd.cpa = virt_to_dma32(cpa);
883
884 return orb;
885}
886
887/**
888 * cp_update_scsw() - update scsw for a channel program.
889 * @cp: channel_program on which to perform the operation
890 * @scsw: I/O results of the channel program and also the target to be
891 * updated
892 *
893 * @scsw contains the I/O results of the channel program that pointed
894 * to by @cp. However what @scsw->cpa stores is a host physical
895 * address, which is meaningless for the guest, which is waiting for
896 * the I/O results.
897 *
898 * This function updates @scsw->cpa to its coressponding guest physical
899 * address.
900 */
901void cp_update_scsw(struct channel_program *cp, union scsw *scsw)
902{
903 struct ccwchain *chain;
904 dma32_t cpa = scsw->cmd.cpa;
905 u32 ccw_head;
906
907 if (!cp->initialized)
908 return;
909
910 /*
911 * LATER:
912 * For now, only update the cmd.cpa part. We may need to deal with
913 * other portions of the schib as well, even if we don't return them
914 * in the ioctl directly. Path status changes etc.
915 */
916 list_for_each_entry(chain, &cp->ccwchain_list, next) {
917 ccw_head = (u32)(u64)chain->ch_ccw;
918 /*
919 * On successful execution, cpa points just beyond the end
920 * of the chain.
921 */
922 if (is_cpa_within_range(cpa, ccw_head, chain->ch_len + 1)) {
923 /*
924 * (cpa - ccw_head) is the offset value of the host
925 * physical ccw to its chain head.
926 * Adding this value to the guest physical ccw chain
927 * head gets us the guest cpa:
928 * cpa = chain->ch_iova + (cpa - ccw_head)
929 */
930 cpa = dma32_add(cpa, chain->ch_iova - ccw_head);
931 break;
932 }
933 }
934
935 scsw->cmd.cpa = cpa;
936}
937
938/**
939 * cp_iova_pinned() - check if an iova is pinned for a ccw chain.
940 * @cp: channel_program on which to perform the operation
941 * @iova: the iova to check
942 * @length: the length to check from @iova
943 *
944 * If the @iova is currently pinned for the ccw chain, return true;
945 * else return false.
946 */
947bool cp_iova_pinned(struct channel_program *cp, u64 iova, u64 length)
948{
949 struct ccwchain *chain;
950 int i;
951
952 if (!cp->initialized)
953 return false;
954
955 list_for_each_entry(chain, &cp->ccwchain_list, next) {
956 for (i = 0; i < chain->ch_len; i++)
957 if (page_array_iova_pinned(&chain->ch_pa[i], iova, length))
958 return true;
959 }
960
961 return false;
962}