xref: /openbmc/linux/arch/s390/kvm/gaccess.c (revision 5c816641)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * guest access functions
4  *
5  * Copyright IBM Corp. 2014
6  *
7  */
8 
9 #include <linux/vmalloc.h>
10 #include <linux/mm_types.h>
11 #include <linux/err.h>
12 #include <linux/pgtable.h>
13 
14 #include <asm/gmap.h>
15 #include "kvm-s390.h"
16 #include "gaccess.h"
17 #include <asm/switch_to.h>
18 
19 union asce {
20 	unsigned long val;
21 	struct {
22 		unsigned long origin : 52; /* Region- or Segment-Table Origin */
23 		unsigned long	 : 2;
24 		unsigned long g  : 1; /* Subspace Group Control */
25 		unsigned long p  : 1; /* Private Space Control */
26 		unsigned long s  : 1; /* Storage-Alteration-Event Control */
27 		unsigned long x  : 1; /* Space-Switch-Event Control */
28 		unsigned long r  : 1; /* Real-Space Control */
29 		unsigned long	 : 1;
30 		unsigned long dt : 2; /* Designation-Type Control */
31 		unsigned long tl : 2; /* Region- or Segment-Table Length */
32 	};
33 };
34 
35 enum {
36 	ASCE_TYPE_SEGMENT = 0,
37 	ASCE_TYPE_REGION3 = 1,
38 	ASCE_TYPE_REGION2 = 2,
39 	ASCE_TYPE_REGION1 = 3
40 };
41 
42 union region1_table_entry {
43 	unsigned long val;
44 	struct {
45 		unsigned long rto: 52;/* Region-Table Origin */
46 		unsigned long	 : 2;
47 		unsigned long p  : 1; /* DAT-Protection Bit */
48 		unsigned long	 : 1;
49 		unsigned long tf : 2; /* Region-Second-Table Offset */
50 		unsigned long i  : 1; /* Region-Invalid Bit */
51 		unsigned long	 : 1;
52 		unsigned long tt : 2; /* Table-Type Bits */
53 		unsigned long tl : 2; /* Region-Second-Table Length */
54 	};
55 };
56 
57 union region2_table_entry {
58 	unsigned long val;
59 	struct {
60 		unsigned long rto: 52;/* Region-Table Origin */
61 		unsigned long	 : 2;
62 		unsigned long p  : 1; /* DAT-Protection Bit */
63 		unsigned long	 : 1;
64 		unsigned long tf : 2; /* Region-Third-Table Offset */
65 		unsigned long i  : 1; /* Region-Invalid Bit */
66 		unsigned long	 : 1;
67 		unsigned long tt : 2; /* Table-Type Bits */
68 		unsigned long tl : 2; /* Region-Third-Table Length */
69 	};
70 };
71 
72 struct region3_table_entry_fc0 {
73 	unsigned long sto: 52;/* Segment-Table Origin */
74 	unsigned long	 : 1;
75 	unsigned long fc : 1; /* Format-Control */
76 	unsigned long p  : 1; /* DAT-Protection Bit */
77 	unsigned long	 : 1;
78 	unsigned long tf : 2; /* Segment-Table Offset */
79 	unsigned long i  : 1; /* Region-Invalid Bit */
80 	unsigned long cr : 1; /* Common-Region Bit */
81 	unsigned long tt : 2; /* Table-Type Bits */
82 	unsigned long tl : 2; /* Segment-Table Length */
83 };
84 
85 struct region3_table_entry_fc1 {
86 	unsigned long rfaa : 33; /* Region-Frame Absolute Address */
87 	unsigned long	 : 14;
88 	unsigned long av : 1; /* ACCF-Validity Control */
89 	unsigned long acc: 4; /* Access-Control Bits */
90 	unsigned long f  : 1; /* Fetch-Protection Bit */
91 	unsigned long fc : 1; /* Format-Control */
92 	unsigned long p  : 1; /* DAT-Protection Bit */
93 	unsigned long iep: 1; /* Instruction-Execution-Protection */
94 	unsigned long	 : 2;
95 	unsigned long i  : 1; /* Region-Invalid Bit */
96 	unsigned long cr : 1; /* Common-Region Bit */
97 	unsigned long tt : 2; /* Table-Type Bits */
98 	unsigned long	 : 2;
99 };
100 
101 union region3_table_entry {
102 	unsigned long val;
103 	struct region3_table_entry_fc0 fc0;
104 	struct region3_table_entry_fc1 fc1;
105 	struct {
106 		unsigned long	 : 53;
107 		unsigned long fc : 1; /* Format-Control */
108 		unsigned long	 : 4;
109 		unsigned long i  : 1; /* Region-Invalid Bit */
110 		unsigned long cr : 1; /* Common-Region Bit */
111 		unsigned long tt : 2; /* Table-Type Bits */
112 		unsigned long	 : 2;
113 	};
114 };
115 
116 struct segment_entry_fc0 {
117 	unsigned long pto: 53;/* Page-Table Origin */
118 	unsigned long fc : 1; /* Format-Control */
119 	unsigned long p  : 1; /* DAT-Protection Bit */
120 	unsigned long	 : 3;
121 	unsigned long i  : 1; /* Segment-Invalid Bit */
122 	unsigned long cs : 1; /* Common-Segment Bit */
123 	unsigned long tt : 2; /* Table-Type Bits */
124 	unsigned long	 : 2;
125 };
126 
127 struct segment_entry_fc1 {
128 	unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
129 	unsigned long	 : 3;
130 	unsigned long av : 1; /* ACCF-Validity Control */
131 	unsigned long acc: 4; /* Access-Control Bits */
132 	unsigned long f  : 1; /* Fetch-Protection Bit */
133 	unsigned long fc : 1; /* Format-Control */
134 	unsigned long p  : 1; /* DAT-Protection Bit */
135 	unsigned long iep: 1; /* Instruction-Execution-Protection */
136 	unsigned long	 : 2;
137 	unsigned long i  : 1; /* Segment-Invalid Bit */
138 	unsigned long cs : 1; /* Common-Segment Bit */
139 	unsigned long tt : 2; /* Table-Type Bits */
140 	unsigned long	 : 2;
141 };
142 
143 union segment_table_entry {
144 	unsigned long val;
145 	struct segment_entry_fc0 fc0;
146 	struct segment_entry_fc1 fc1;
147 	struct {
148 		unsigned long	 : 53;
149 		unsigned long fc : 1; /* Format-Control */
150 		unsigned long	 : 4;
151 		unsigned long i  : 1; /* Segment-Invalid Bit */
152 		unsigned long cs : 1; /* Common-Segment Bit */
153 		unsigned long tt : 2; /* Table-Type Bits */
154 		unsigned long	 : 2;
155 	};
156 };
157 
158 enum {
159 	TABLE_TYPE_SEGMENT = 0,
160 	TABLE_TYPE_REGION3 = 1,
161 	TABLE_TYPE_REGION2 = 2,
162 	TABLE_TYPE_REGION1 = 3
163 };
164 
165 union page_table_entry {
166 	unsigned long val;
167 	struct {
168 		unsigned long pfra : 52; /* Page-Frame Real Address */
169 		unsigned long z  : 1; /* Zero Bit */
170 		unsigned long i  : 1; /* Page-Invalid Bit */
171 		unsigned long p  : 1; /* DAT-Protection Bit */
172 		unsigned long iep: 1; /* Instruction-Execution-Protection */
173 		unsigned long	 : 8;
174 	};
175 };
176 
177 /*
178  * vaddress union in order to easily decode a virtual address into its
179  * region first index, region second index etc. parts.
180  */
181 union vaddress {
182 	unsigned long addr;
183 	struct {
184 		unsigned long rfx : 11;
185 		unsigned long rsx : 11;
186 		unsigned long rtx : 11;
187 		unsigned long sx  : 11;
188 		unsigned long px  : 8;
189 		unsigned long bx  : 12;
190 	};
191 	struct {
192 		unsigned long rfx01 : 2;
193 		unsigned long	    : 9;
194 		unsigned long rsx01 : 2;
195 		unsigned long	    : 9;
196 		unsigned long rtx01 : 2;
197 		unsigned long	    : 9;
198 		unsigned long sx01  : 2;
199 		unsigned long	    : 29;
200 	};
201 };
202 
203 /*
204  * raddress union which will contain the result (real or absolute address)
205  * after a page table walk. The rfaa, sfaa and pfra members are used to
206  * simply assign them the value of a region, segment or page table entry.
207  */
208 union raddress {
209 	unsigned long addr;
210 	unsigned long rfaa : 33; /* Region-Frame Absolute Address */
211 	unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
212 	unsigned long pfra : 52; /* Page-Frame Real Address */
213 };
214 
215 union alet {
216 	u32 val;
217 	struct {
218 		u32 reserved : 7;
219 		u32 p        : 1;
220 		u32 alesn    : 8;
221 		u32 alen     : 16;
222 	};
223 };
224 
225 union ald {
226 	u32 val;
227 	struct {
228 		u32     : 1;
229 		u32 alo : 24;
230 		u32 all : 7;
231 	};
232 };
233 
234 struct ale {
235 	unsigned long i      : 1; /* ALEN-Invalid Bit */
236 	unsigned long        : 5;
237 	unsigned long fo     : 1; /* Fetch-Only Bit */
238 	unsigned long p      : 1; /* Private Bit */
239 	unsigned long alesn  : 8; /* Access-List-Entry Sequence Number */
240 	unsigned long aleax  : 16; /* Access-List-Entry Authorization Index */
241 	unsigned long        : 32;
242 	unsigned long        : 1;
243 	unsigned long asteo  : 25; /* ASN-Second-Table-Entry Origin */
244 	unsigned long        : 6;
245 	unsigned long astesn : 32; /* ASTE Sequence Number */
246 };
247 
248 struct aste {
249 	unsigned long i      : 1; /* ASX-Invalid Bit */
250 	unsigned long ato    : 29; /* Authority-Table Origin */
251 	unsigned long        : 1;
252 	unsigned long b      : 1; /* Base-Space Bit */
253 	unsigned long ax     : 16; /* Authorization Index */
254 	unsigned long atl    : 12; /* Authority-Table Length */
255 	unsigned long        : 2;
256 	unsigned long ca     : 1; /* Controlled-ASN Bit */
257 	unsigned long ra     : 1; /* Reusable-ASN Bit */
258 	unsigned long asce   : 64; /* Address-Space-Control Element */
259 	unsigned long ald    : 32;
260 	unsigned long astesn : 32;
261 	/* .. more fields there */
262 };
263 
264 int ipte_lock_held(struct kvm_vcpu *vcpu)
265 {
266 	if (vcpu->arch.sie_block->eca & ECA_SII) {
267 		int rc;
268 
269 		read_lock(&vcpu->kvm->arch.sca_lock);
270 		rc = kvm_s390_get_ipte_control(vcpu->kvm)->kh != 0;
271 		read_unlock(&vcpu->kvm->arch.sca_lock);
272 		return rc;
273 	}
274 	return vcpu->kvm->arch.ipte_lock_count != 0;
275 }
276 
277 static void ipte_lock_simple(struct kvm_vcpu *vcpu)
278 {
279 	union ipte_control old, new, *ic;
280 
281 	mutex_lock(&vcpu->kvm->arch.ipte_mutex);
282 	vcpu->kvm->arch.ipte_lock_count++;
283 	if (vcpu->kvm->arch.ipte_lock_count > 1)
284 		goto out;
285 retry:
286 	read_lock(&vcpu->kvm->arch.sca_lock);
287 	ic = kvm_s390_get_ipte_control(vcpu->kvm);
288 	do {
289 		old = READ_ONCE(*ic);
290 		if (old.k) {
291 			read_unlock(&vcpu->kvm->arch.sca_lock);
292 			cond_resched();
293 			goto retry;
294 		}
295 		new = old;
296 		new.k = 1;
297 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
298 	read_unlock(&vcpu->kvm->arch.sca_lock);
299 out:
300 	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
301 }
302 
303 static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
304 {
305 	union ipte_control old, new, *ic;
306 
307 	mutex_lock(&vcpu->kvm->arch.ipte_mutex);
308 	vcpu->kvm->arch.ipte_lock_count--;
309 	if (vcpu->kvm->arch.ipte_lock_count)
310 		goto out;
311 	read_lock(&vcpu->kvm->arch.sca_lock);
312 	ic = kvm_s390_get_ipte_control(vcpu->kvm);
313 	do {
314 		old = READ_ONCE(*ic);
315 		new = old;
316 		new.k = 0;
317 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
318 	read_unlock(&vcpu->kvm->arch.sca_lock);
319 	wake_up(&vcpu->kvm->arch.ipte_wq);
320 out:
321 	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
322 }
323 
324 static void ipte_lock_siif(struct kvm_vcpu *vcpu)
325 {
326 	union ipte_control old, new, *ic;
327 
328 retry:
329 	read_lock(&vcpu->kvm->arch.sca_lock);
330 	ic = kvm_s390_get_ipte_control(vcpu->kvm);
331 	do {
332 		old = READ_ONCE(*ic);
333 		if (old.kg) {
334 			read_unlock(&vcpu->kvm->arch.sca_lock);
335 			cond_resched();
336 			goto retry;
337 		}
338 		new = old;
339 		new.k = 1;
340 		new.kh++;
341 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
342 	read_unlock(&vcpu->kvm->arch.sca_lock);
343 }
344 
345 static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
346 {
347 	union ipte_control old, new, *ic;
348 
349 	read_lock(&vcpu->kvm->arch.sca_lock);
350 	ic = kvm_s390_get_ipte_control(vcpu->kvm);
351 	do {
352 		old = READ_ONCE(*ic);
353 		new = old;
354 		new.kh--;
355 		if (!new.kh)
356 			new.k = 0;
357 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
358 	read_unlock(&vcpu->kvm->arch.sca_lock);
359 	if (!new.kh)
360 		wake_up(&vcpu->kvm->arch.ipte_wq);
361 }
362 
363 void ipte_lock(struct kvm_vcpu *vcpu)
364 {
365 	if (vcpu->arch.sie_block->eca & ECA_SII)
366 		ipte_lock_siif(vcpu);
367 	else
368 		ipte_lock_simple(vcpu);
369 }
370 
371 void ipte_unlock(struct kvm_vcpu *vcpu)
372 {
373 	if (vcpu->arch.sie_block->eca & ECA_SII)
374 		ipte_unlock_siif(vcpu);
375 	else
376 		ipte_unlock_simple(vcpu);
377 }
378 
379 static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar,
380 			  enum gacc_mode mode)
381 {
382 	union alet alet;
383 	struct ale ale;
384 	struct aste aste;
385 	unsigned long ald_addr, authority_table_addr;
386 	union ald ald;
387 	int eax, rc;
388 	u8 authority_table;
389 
390 	if (ar >= NUM_ACRS)
391 		return -EINVAL;
392 
393 	save_access_regs(vcpu->run->s.regs.acrs);
394 	alet.val = vcpu->run->s.regs.acrs[ar];
395 
396 	if (ar == 0 || alet.val == 0) {
397 		asce->val = vcpu->arch.sie_block->gcr[1];
398 		return 0;
399 	} else if (alet.val == 1) {
400 		asce->val = vcpu->arch.sie_block->gcr[7];
401 		return 0;
402 	}
403 
404 	if (alet.reserved)
405 		return PGM_ALET_SPECIFICATION;
406 
407 	if (alet.p)
408 		ald_addr = vcpu->arch.sie_block->gcr[5];
409 	else
410 		ald_addr = vcpu->arch.sie_block->gcr[2];
411 	ald_addr &= 0x7fffffc0;
412 
413 	rc = read_guest_real(vcpu, ald_addr + 16, &ald.val, sizeof(union ald));
414 	if (rc)
415 		return rc;
416 
417 	if (alet.alen / 8 > ald.all)
418 		return PGM_ALEN_TRANSLATION;
419 
420 	if (0x7fffffff - ald.alo * 128 < alet.alen * 16)
421 		return PGM_ADDRESSING;
422 
423 	rc = read_guest_real(vcpu, ald.alo * 128 + alet.alen * 16, &ale,
424 			     sizeof(struct ale));
425 	if (rc)
426 		return rc;
427 
428 	if (ale.i == 1)
429 		return PGM_ALEN_TRANSLATION;
430 	if (ale.alesn != alet.alesn)
431 		return PGM_ALE_SEQUENCE;
432 
433 	rc = read_guest_real(vcpu, ale.asteo * 64, &aste, sizeof(struct aste));
434 	if (rc)
435 		return rc;
436 
437 	if (aste.i)
438 		return PGM_ASTE_VALIDITY;
439 	if (aste.astesn != ale.astesn)
440 		return PGM_ASTE_SEQUENCE;
441 
442 	if (ale.p == 1) {
443 		eax = (vcpu->arch.sie_block->gcr[8] >> 16) & 0xffff;
444 		if (ale.aleax != eax) {
445 			if (eax / 16 > aste.atl)
446 				return PGM_EXTENDED_AUTHORITY;
447 
448 			authority_table_addr = aste.ato * 4 + eax / 4;
449 
450 			rc = read_guest_real(vcpu, authority_table_addr,
451 					     &authority_table,
452 					     sizeof(u8));
453 			if (rc)
454 				return rc;
455 
456 			if ((authority_table & (0x40 >> ((eax & 3) * 2))) == 0)
457 				return PGM_EXTENDED_AUTHORITY;
458 		}
459 	}
460 
461 	if (ale.fo == 1 && mode == GACC_STORE)
462 		return PGM_PROTECTION;
463 
464 	asce->val = aste.asce;
465 	return 0;
466 }
467 
468 struct trans_exc_code_bits {
469 	unsigned long addr : 52; /* Translation-exception Address */
470 	unsigned long fsi  : 2;  /* Access Exception Fetch/Store Indication */
471 	unsigned long	   : 2;
472 	unsigned long b56  : 1;
473 	unsigned long	   : 3;
474 	unsigned long b60  : 1;
475 	unsigned long b61  : 1;
476 	unsigned long as   : 2;  /* ASCE Identifier */
477 };
478 
479 enum {
480 	FSI_UNKNOWN = 0, /* Unknown wether fetch or store */
481 	FSI_STORE   = 1, /* Exception was due to store operation */
482 	FSI_FETCH   = 2  /* Exception was due to fetch operation */
483 };
484 
485 enum prot_type {
486 	PROT_TYPE_LA   = 0,
487 	PROT_TYPE_KEYC = 1,
488 	PROT_TYPE_ALC  = 2,
489 	PROT_TYPE_DAT  = 3,
490 	PROT_TYPE_IEP  = 4,
491 };
492 
493 static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva,
494 		     u8 ar, enum gacc_mode mode, enum prot_type prot)
495 {
496 	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
497 	struct trans_exc_code_bits *tec;
498 
499 	memset(pgm, 0, sizeof(*pgm));
500 	pgm->code = code;
501 	tec = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
502 
503 	switch (code) {
504 	case PGM_PROTECTION:
505 		switch (prot) {
506 		case PROT_TYPE_IEP:
507 			tec->b61 = 1;
508 			fallthrough;
509 		case PROT_TYPE_LA:
510 			tec->b56 = 1;
511 			break;
512 		case PROT_TYPE_KEYC:
513 			tec->b60 = 1;
514 			break;
515 		case PROT_TYPE_ALC:
516 			tec->b60 = 1;
517 			fallthrough;
518 		case PROT_TYPE_DAT:
519 			tec->b61 = 1;
520 			break;
521 		}
522 		fallthrough;
523 	case PGM_ASCE_TYPE:
524 	case PGM_PAGE_TRANSLATION:
525 	case PGM_REGION_FIRST_TRANS:
526 	case PGM_REGION_SECOND_TRANS:
527 	case PGM_REGION_THIRD_TRANS:
528 	case PGM_SEGMENT_TRANSLATION:
529 		/*
530 		 * op_access_id only applies to MOVE_PAGE -> set bit 61
531 		 * exc_access_id has to be set to 0 for some instructions. Both
532 		 * cases have to be handled by the caller.
533 		 */
534 		tec->addr = gva >> PAGE_SHIFT;
535 		tec->fsi = mode == GACC_STORE ? FSI_STORE : FSI_FETCH;
536 		tec->as = psw_bits(vcpu->arch.sie_block->gpsw).as;
537 		fallthrough;
538 	case PGM_ALEN_TRANSLATION:
539 	case PGM_ALE_SEQUENCE:
540 	case PGM_ASTE_VALIDITY:
541 	case PGM_ASTE_SEQUENCE:
542 	case PGM_EXTENDED_AUTHORITY:
543 		/*
544 		 * We can always store exc_access_id, as it is
545 		 * undefined for non-ar cases. It is undefined for
546 		 * most DAT protection exceptions.
547 		 */
548 		pgm->exc_access_id = ar;
549 		break;
550 	}
551 	return code;
552 }
553 
554 static int get_vcpu_asce(struct kvm_vcpu *vcpu, union asce *asce,
555 			 unsigned long ga, u8 ar, enum gacc_mode mode)
556 {
557 	int rc;
558 	struct psw_bits psw = psw_bits(vcpu->arch.sie_block->gpsw);
559 
560 	if (!psw.dat) {
561 		asce->val = 0;
562 		asce->r = 1;
563 		return 0;
564 	}
565 
566 	if ((mode == GACC_IFETCH) && (psw.as != PSW_BITS_AS_HOME))
567 		psw.as = PSW_BITS_AS_PRIMARY;
568 
569 	switch (psw.as) {
570 	case PSW_BITS_AS_PRIMARY:
571 		asce->val = vcpu->arch.sie_block->gcr[1];
572 		return 0;
573 	case PSW_BITS_AS_SECONDARY:
574 		asce->val = vcpu->arch.sie_block->gcr[7];
575 		return 0;
576 	case PSW_BITS_AS_HOME:
577 		asce->val = vcpu->arch.sie_block->gcr[13];
578 		return 0;
579 	case PSW_BITS_AS_ACCREG:
580 		rc = ar_translation(vcpu, asce, ar, mode);
581 		if (rc > 0)
582 			return trans_exc(vcpu, rc, ga, ar, mode, PROT_TYPE_ALC);
583 		return rc;
584 	}
585 	return 0;
586 }
587 
588 static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val)
589 {
590 	return kvm_read_guest(kvm, gpa, val, sizeof(*val));
591 }
592 
593 /**
594  * guest_translate - translate a guest virtual into a guest absolute address
595  * @vcpu: virtual cpu
596  * @gva: guest virtual address
597  * @gpa: points to where guest physical (absolute) address should be stored
598  * @asce: effective asce
599  * @mode: indicates the access mode to be used
600  * @prot: returns the type for protection exceptions
601  *
602  * Translate a guest virtual address into a guest absolute address by means
603  * of dynamic address translation as specified by the architecture.
604  * If the resulting absolute address is not available in the configuration
605  * an addressing exception is indicated and @gpa will not be changed.
606  *
607  * Returns: - zero on success; @gpa contains the resulting absolute address
608  *	    - a negative value if guest access failed due to e.g. broken
609  *	      guest mapping
610  *	    - a positve value if an access exception happened. In this case
611  *	      the returned value is the program interruption code as defined
612  *	      by the architecture
613  */
614 static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
615 				     unsigned long *gpa, const union asce asce,
616 				     enum gacc_mode mode, enum prot_type *prot)
617 {
618 	union vaddress vaddr = {.addr = gva};
619 	union raddress raddr = {.addr = gva};
620 	union page_table_entry pte;
621 	int dat_protection = 0;
622 	int iep_protection = 0;
623 	union ctlreg0 ctlreg0;
624 	unsigned long ptr;
625 	int edat1, edat2, iep;
626 
627 	ctlreg0.val = vcpu->arch.sie_block->gcr[0];
628 	edat1 = ctlreg0.edat && test_kvm_facility(vcpu->kvm, 8);
629 	edat2 = edat1 && test_kvm_facility(vcpu->kvm, 78);
630 	iep = ctlreg0.iep && test_kvm_facility(vcpu->kvm, 130);
631 	if (asce.r)
632 		goto real_address;
633 	ptr = asce.origin * PAGE_SIZE;
634 	switch (asce.dt) {
635 	case ASCE_TYPE_REGION1:
636 		if (vaddr.rfx01 > asce.tl)
637 			return PGM_REGION_FIRST_TRANS;
638 		ptr += vaddr.rfx * 8;
639 		break;
640 	case ASCE_TYPE_REGION2:
641 		if (vaddr.rfx)
642 			return PGM_ASCE_TYPE;
643 		if (vaddr.rsx01 > asce.tl)
644 			return PGM_REGION_SECOND_TRANS;
645 		ptr += vaddr.rsx * 8;
646 		break;
647 	case ASCE_TYPE_REGION3:
648 		if (vaddr.rfx || vaddr.rsx)
649 			return PGM_ASCE_TYPE;
650 		if (vaddr.rtx01 > asce.tl)
651 			return PGM_REGION_THIRD_TRANS;
652 		ptr += vaddr.rtx * 8;
653 		break;
654 	case ASCE_TYPE_SEGMENT:
655 		if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
656 			return PGM_ASCE_TYPE;
657 		if (vaddr.sx01 > asce.tl)
658 			return PGM_SEGMENT_TRANSLATION;
659 		ptr += vaddr.sx * 8;
660 		break;
661 	}
662 	switch (asce.dt) {
663 	case ASCE_TYPE_REGION1:	{
664 		union region1_table_entry rfte;
665 
666 		if (kvm_is_error_gpa(vcpu->kvm, ptr))
667 			return PGM_ADDRESSING;
668 		if (deref_table(vcpu->kvm, ptr, &rfte.val))
669 			return -EFAULT;
670 		if (rfte.i)
671 			return PGM_REGION_FIRST_TRANS;
672 		if (rfte.tt != TABLE_TYPE_REGION1)
673 			return PGM_TRANSLATION_SPEC;
674 		if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
675 			return PGM_REGION_SECOND_TRANS;
676 		if (edat1)
677 			dat_protection |= rfte.p;
678 		ptr = rfte.rto * PAGE_SIZE + vaddr.rsx * 8;
679 	}
680 		fallthrough;
681 	case ASCE_TYPE_REGION2: {
682 		union region2_table_entry rste;
683 
684 		if (kvm_is_error_gpa(vcpu->kvm, ptr))
685 			return PGM_ADDRESSING;
686 		if (deref_table(vcpu->kvm, ptr, &rste.val))
687 			return -EFAULT;
688 		if (rste.i)
689 			return PGM_REGION_SECOND_TRANS;
690 		if (rste.tt != TABLE_TYPE_REGION2)
691 			return PGM_TRANSLATION_SPEC;
692 		if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
693 			return PGM_REGION_THIRD_TRANS;
694 		if (edat1)
695 			dat_protection |= rste.p;
696 		ptr = rste.rto * PAGE_SIZE + vaddr.rtx * 8;
697 	}
698 		fallthrough;
699 	case ASCE_TYPE_REGION3: {
700 		union region3_table_entry rtte;
701 
702 		if (kvm_is_error_gpa(vcpu->kvm, ptr))
703 			return PGM_ADDRESSING;
704 		if (deref_table(vcpu->kvm, ptr, &rtte.val))
705 			return -EFAULT;
706 		if (rtte.i)
707 			return PGM_REGION_THIRD_TRANS;
708 		if (rtte.tt != TABLE_TYPE_REGION3)
709 			return PGM_TRANSLATION_SPEC;
710 		if (rtte.cr && asce.p && edat2)
711 			return PGM_TRANSLATION_SPEC;
712 		if (rtte.fc && edat2) {
713 			dat_protection |= rtte.fc1.p;
714 			iep_protection = rtte.fc1.iep;
715 			raddr.rfaa = rtte.fc1.rfaa;
716 			goto absolute_address;
717 		}
718 		if (vaddr.sx01 < rtte.fc0.tf)
719 			return PGM_SEGMENT_TRANSLATION;
720 		if (vaddr.sx01 > rtte.fc0.tl)
721 			return PGM_SEGMENT_TRANSLATION;
722 		if (edat1)
723 			dat_protection |= rtte.fc0.p;
724 		ptr = rtte.fc0.sto * PAGE_SIZE + vaddr.sx * 8;
725 	}
726 		fallthrough;
727 	case ASCE_TYPE_SEGMENT: {
728 		union segment_table_entry ste;
729 
730 		if (kvm_is_error_gpa(vcpu->kvm, ptr))
731 			return PGM_ADDRESSING;
732 		if (deref_table(vcpu->kvm, ptr, &ste.val))
733 			return -EFAULT;
734 		if (ste.i)
735 			return PGM_SEGMENT_TRANSLATION;
736 		if (ste.tt != TABLE_TYPE_SEGMENT)
737 			return PGM_TRANSLATION_SPEC;
738 		if (ste.cs && asce.p)
739 			return PGM_TRANSLATION_SPEC;
740 		if (ste.fc && edat1) {
741 			dat_protection |= ste.fc1.p;
742 			iep_protection = ste.fc1.iep;
743 			raddr.sfaa = ste.fc1.sfaa;
744 			goto absolute_address;
745 		}
746 		dat_protection |= ste.fc0.p;
747 		ptr = ste.fc0.pto * (PAGE_SIZE / 2) + vaddr.px * 8;
748 	}
749 	}
750 	if (kvm_is_error_gpa(vcpu->kvm, ptr))
751 		return PGM_ADDRESSING;
752 	if (deref_table(vcpu->kvm, ptr, &pte.val))
753 		return -EFAULT;
754 	if (pte.i)
755 		return PGM_PAGE_TRANSLATION;
756 	if (pte.z)
757 		return PGM_TRANSLATION_SPEC;
758 	dat_protection |= pte.p;
759 	iep_protection = pte.iep;
760 	raddr.pfra = pte.pfra;
761 real_address:
762 	raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr);
763 absolute_address:
764 	if (mode == GACC_STORE && dat_protection) {
765 		*prot = PROT_TYPE_DAT;
766 		return PGM_PROTECTION;
767 	}
768 	if (mode == GACC_IFETCH && iep_protection && iep) {
769 		*prot = PROT_TYPE_IEP;
770 		return PGM_PROTECTION;
771 	}
772 	if (kvm_is_error_gpa(vcpu->kvm, raddr.addr))
773 		return PGM_ADDRESSING;
774 	*gpa = raddr.addr;
775 	return 0;
776 }
777 
778 static inline int is_low_address(unsigned long ga)
779 {
780 	/* Check for address ranges 0..511 and 4096..4607 */
781 	return (ga & ~0x11fful) == 0;
782 }
783 
784 static int low_address_protection_enabled(struct kvm_vcpu *vcpu,
785 					  const union asce asce)
786 {
787 	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
788 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
789 
790 	if (!ctlreg0.lap)
791 		return 0;
792 	if (psw_bits(*psw).dat && asce.p)
793 		return 0;
794 	return 1;
795 }
796 
797 /**
798  * guest_range_to_gpas() - Calculate guest physical addresses of page fragments
799  * covering a logical range
800  * @vcpu: virtual cpu
801  * @ga: guest address, start of range
802  * @ar: access register
803  * @gpas: output argument, may be NULL
804  * @len: length of range in bytes
805  * @asce: address-space-control element to use for translation
806  * @mode: access mode
807  *
808  * Translate a logical range to a series of guest absolute addresses,
809  * such that the concatenation of page fragments starting at each gpa make up
810  * the whole range.
811  * The translation is performed as if done by the cpu for the given @asce, @ar,
812  * @mode and state of the @vcpu.
813  * If the translation causes an exception, its program interruption code is
814  * returned and the &struct kvm_s390_pgm_info pgm member of @vcpu is modified
815  * such that a subsequent call to kvm_s390_inject_prog_vcpu() will inject
816  * a correct exception into the guest.
817  * The resulting gpas are stored into @gpas, unless it is NULL.
818  *
819  * Note: All fragments except the first one start at the beginning of a page.
820  *	 When deriving the boundaries of a fragment from a gpa, all but the last
821  *	 fragment end at the end of the page.
822  *
823  * Return:
824  * * 0		- success
825  * * <0		- translation could not be performed, for example if  guest
826  *		  memory could not be accessed
827  * * >0		- an access exception occurred. In this case the returned value
828  *		  is the program interruption code and the contents of pgm may
829  *		  be used to inject an exception into the guest.
830  */
831 static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
832 			       unsigned long *gpas, unsigned long len,
833 			       const union asce asce, enum gacc_mode mode)
834 {
835 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
836 	unsigned int offset = offset_in_page(ga);
837 	unsigned int fragment_len;
838 	int lap_enabled, rc = 0;
839 	enum prot_type prot;
840 	unsigned long gpa;
841 
842 	lap_enabled = low_address_protection_enabled(vcpu, asce);
843 	while (min(PAGE_SIZE - offset, len) > 0) {
844 		fragment_len = min(PAGE_SIZE - offset, len);
845 		ga = kvm_s390_logical_to_effective(vcpu, ga);
846 		if (mode == GACC_STORE && lap_enabled && is_low_address(ga))
847 			return trans_exc(vcpu, PGM_PROTECTION, ga, ar, mode,
848 					 PROT_TYPE_LA);
849 		if (psw_bits(*psw).dat) {
850 			rc = guest_translate(vcpu, ga, &gpa, asce, mode, &prot);
851 			if (rc < 0)
852 				return rc;
853 		} else {
854 			gpa = kvm_s390_real_to_abs(vcpu, ga);
855 			if (kvm_is_error_gpa(vcpu->kvm, gpa))
856 				rc = PGM_ADDRESSING;
857 		}
858 		if (rc)
859 			return trans_exc(vcpu, rc, ga, ar, mode, prot);
860 		if (gpas)
861 			*gpas++ = gpa;
862 		offset = 0;
863 		ga += fragment_len;
864 		len -= fragment_len;
865 	}
866 	return 0;
867 }
868 
869 static int access_guest_page(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa,
870 			     void *data, unsigned int len)
871 {
872 	const unsigned int offset = offset_in_page(gpa);
873 	const gfn_t gfn = gpa_to_gfn(gpa);
874 	int rc;
875 
876 	if (mode == GACC_STORE)
877 		rc = kvm_write_guest_page(kvm, gfn, data, offset, len);
878 	else
879 		rc = kvm_read_guest_page(kvm, gfn, data, offset, len);
880 	return rc;
881 }
882 
883 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
884 		 unsigned long len, enum gacc_mode mode)
885 {
886 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
887 	unsigned long nr_pages, idx;
888 	unsigned long gpa_array[2];
889 	unsigned int fragment_len;
890 	unsigned long *gpas;
891 	int need_ipte_lock;
892 	union asce asce;
893 	int rc;
894 
895 	if (!len)
896 		return 0;
897 	ga = kvm_s390_logical_to_effective(vcpu, ga);
898 	rc = get_vcpu_asce(vcpu, &asce, ga, ar, mode);
899 	if (rc)
900 		return rc;
901 	nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1;
902 	gpas = gpa_array;
903 	if (nr_pages > ARRAY_SIZE(gpa_array))
904 		gpas = vmalloc(array_size(nr_pages, sizeof(unsigned long)));
905 	if (!gpas)
906 		return -ENOMEM;
907 	need_ipte_lock = psw_bits(*psw).dat && !asce.r;
908 	if (need_ipte_lock)
909 		ipte_lock(vcpu);
910 	rc = guest_range_to_gpas(vcpu, ga, ar, gpas, len, asce, mode);
911 	for (idx = 0; idx < nr_pages && !rc; idx++) {
912 		fragment_len = min(PAGE_SIZE - offset_in_page(gpas[idx]), len);
913 		rc = access_guest_page(vcpu->kvm, mode, gpas[idx], data, fragment_len);
914 		len -= fragment_len;
915 		data += fragment_len;
916 	}
917 	if (need_ipte_lock)
918 		ipte_unlock(vcpu);
919 	if (nr_pages > ARRAY_SIZE(gpa_array))
920 		vfree(gpas);
921 	return rc;
922 }
923 
924 int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
925 		      void *data, unsigned long len, enum gacc_mode mode)
926 {
927 	unsigned int fragment_len;
928 	unsigned long gpa;
929 	int rc = 0;
930 
931 	while (len && !rc) {
932 		gpa = kvm_s390_real_to_abs(vcpu, gra);
933 		fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len);
934 		rc = access_guest_page(vcpu->kvm, mode, gpa, data, fragment_len);
935 		len -= fragment_len;
936 		gra += fragment_len;
937 		data += fragment_len;
938 	}
939 	return rc;
940 }
941 
942 /**
943  * guest_translate_address - translate guest logical into guest absolute address
944  * @vcpu: virtual cpu
945  * @gva: Guest virtual address
946  * @ar: Access register
947  * @gpa: Guest physical address
948  * @mode: Translation access mode
949  *
950  * Parameter semantics are the same as the ones from guest_translate.
951  * The memory contents at the guest address are not changed.
952  *
953  * Note: The IPTE lock is not taken during this function, so the caller
954  * has to take care of this.
955  */
956 int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
957 			    unsigned long *gpa, enum gacc_mode mode)
958 {
959 	union asce asce;
960 	int rc;
961 
962 	gva = kvm_s390_logical_to_effective(vcpu, gva);
963 	rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
964 	if (rc)
965 		return rc;
966 	return guest_range_to_gpas(vcpu, gva, ar, gpa, 1, asce, mode);
967 }
968 
969 /**
970  * check_gva_range - test a range of guest virtual addresses for accessibility
971  * @vcpu: virtual cpu
972  * @gva: Guest virtual address
973  * @ar: Access register
974  * @length: Length of test range
975  * @mode: Translation access mode
976  */
977 int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
978 		    unsigned long length, enum gacc_mode mode)
979 {
980 	union asce asce;
981 	int rc = 0;
982 
983 	rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode);
984 	if (rc)
985 		return rc;
986 	ipte_lock(vcpu);
987 	rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode);
988 	ipte_unlock(vcpu);
989 
990 	return rc;
991 }
992 
993 /**
994  * kvm_s390_check_low_addr_prot_real - check for low-address protection
995  * @vcpu: virtual cpu
996  * @gra: Guest real address
997  *
998  * Checks whether an address is subject to low-address protection and set
999  * up vcpu->arch.pgm accordingly if necessary.
1000  *
1001  * Return: 0 if no protection exception, or PGM_PROTECTION if protected.
1002  */
1003 int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra)
1004 {
1005 	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
1006 
1007 	if (!ctlreg0.lap || !is_low_address(gra))
1008 		return 0;
1009 	return trans_exc(vcpu, PGM_PROTECTION, gra, 0, GACC_STORE, PROT_TYPE_LA);
1010 }
1011 
1012 /**
1013  * kvm_s390_shadow_tables - walk the guest page table and create shadow tables
1014  * @sg: pointer to the shadow guest address space structure
1015  * @saddr: faulting address in the shadow gmap
1016  * @pgt: pointer to the beginning of the page table for the given address if
1017  *	 successful (return value 0), or to the first invalid DAT entry in
1018  *	 case of exceptions (return value > 0)
1019  * @dat_protection: referenced memory is write protected
1020  * @fake: pgt references contiguous guest memory block, not a pgtable
1021  */
1022 static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
1023 				  unsigned long *pgt, int *dat_protection,
1024 				  int *fake)
1025 {
1026 	struct gmap *parent;
1027 	union asce asce;
1028 	union vaddress vaddr;
1029 	unsigned long ptr;
1030 	int rc;
1031 
1032 	*fake = 0;
1033 	*dat_protection = 0;
1034 	parent = sg->parent;
1035 	vaddr.addr = saddr;
1036 	asce.val = sg->orig_asce;
1037 	ptr = asce.origin * PAGE_SIZE;
1038 	if (asce.r) {
1039 		*fake = 1;
1040 		ptr = 0;
1041 		asce.dt = ASCE_TYPE_REGION1;
1042 	}
1043 	switch (asce.dt) {
1044 	case ASCE_TYPE_REGION1:
1045 		if (vaddr.rfx01 > asce.tl && !*fake)
1046 			return PGM_REGION_FIRST_TRANS;
1047 		break;
1048 	case ASCE_TYPE_REGION2:
1049 		if (vaddr.rfx)
1050 			return PGM_ASCE_TYPE;
1051 		if (vaddr.rsx01 > asce.tl)
1052 			return PGM_REGION_SECOND_TRANS;
1053 		break;
1054 	case ASCE_TYPE_REGION3:
1055 		if (vaddr.rfx || vaddr.rsx)
1056 			return PGM_ASCE_TYPE;
1057 		if (vaddr.rtx01 > asce.tl)
1058 			return PGM_REGION_THIRD_TRANS;
1059 		break;
1060 	case ASCE_TYPE_SEGMENT:
1061 		if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
1062 			return PGM_ASCE_TYPE;
1063 		if (vaddr.sx01 > asce.tl)
1064 			return PGM_SEGMENT_TRANSLATION;
1065 		break;
1066 	}
1067 
1068 	switch (asce.dt) {
1069 	case ASCE_TYPE_REGION1: {
1070 		union region1_table_entry rfte;
1071 
1072 		if (*fake) {
1073 			ptr += vaddr.rfx * _REGION1_SIZE;
1074 			rfte.val = ptr;
1075 			goto shadow_r2t;
1076 		}
1077 		*pgt = ptr + vaddr.rfx * 8;
1078 		rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val);
1079 		if (rc)
1080 			return rc;
1081 		if (rfte.i)
1082 			return PGM_REGION_FIRST_TRANS;
1083 		if (rfte.tt != TABLE_TYPE_REGION1)
1084 			return PGM_TRANSLATION_SPEC;
1085 		if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
1086 			return PGM_REGION_SECOND_TRANS;
1087 		if (sg->edat_level >= 1)
1088 			*dat_protection |= rfte.p;
1089 		ptr = rfte.rto * PAGE_SIZE;
1090 shadow_r2t:
1091 		rc = gmap_shadow_r2t(sg, saddr, rfte.val, *fake);
1092 		if (rc)
1093 			return rc;
1094 	}
1095 		fallthrough;
1096 	case ASCE_TYPE_REGION2: {
1097 		union region2_table_entry rste;
1098 
1099 		if (*fake) {
1100 			ptr += vaddr.rsx * _REGION2_SIZE;
1101 			rste.val = ptr;
1102 			goto shadow_r3t;
1103 		}
1104 		*pgt = ptr + vaddr.rsx * 8;
1105 		rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val);
1106 		if (rc)
1107 			return rc;
1108 		if (rste.i)
1109 			return PGM_REGION_SECOND_TRANS;
1110 		if (rste.tt != TABLE_TYPE_REGION2)
1111 			return PGM_TRANSLATION_SPEC;
1112 		if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
1113 			return PGM_REGION_THIRD_TRANS;
1114 		if (sg->edat_level >= 1)
1115 			*dat_protection |= rste.p;
1116 		ptr = rste.rto * PAGE_SIZE;
1117 shadow_r3t:
1118 		rste.p |= *dat_protection;
1119 		rc = gmap_shadow_r3t(sg, saddr, rste.val, *fake);
1120 		if (rc)
1121 			return rc;
1122 	}
1123 		fallthrough;
1124 	case ASCE_TYPE_REGION3: {
1125 		union region3_table_entry rtte;
1126 
1127 		if (*fake) {
1128 			ptr += vaddr.rtx * _REGION3_SIZE;
1129 			rtte.val = ptr;
1130 			goto shadow_sgt;
1131 		}
1132 		*pgt = ptr + vaddr.rtx * 8;
1133 		rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val);
1134 		if (rc)
1135 			return rc;
1136 		if (rtte.i)
1137 			return PGM_REGION_THIRD_TRANS;
1138 		if (rtte.tt != TABLE_TYPE_REGION3)
1139 			return PGM_TRANSLATION_SPEC;
1140 		if (rtte.cr && asce.p && sg->edat_level >= 2)
1141 			return PGM_TRANSLATION_SPEC;
1142 		if (rtte.fc && sg->edat_level >= 2) {
1143 			*dat_protection |= rtte.fc0.p;
1144 			*fake = 1;
1145 			ptr = rtte.fc1.rfaa * _REGION3_SIZE;
1146 			rtte.val = ptr;
1147 			goto shadow_sgt;
1148 		}
1149 		if (vaddr.sx01 < rtte.fc0.tf || vaddr.sx01 > rtte.fc0.tl)
1150 			return PGM_SEGMENT_TRANSLATION;
1151 		if (sg->edat_level >= 1)
1152 			*dat_protection |= rtte.fc0.p;
1153 		ptr = rtte.fc0.sto * PAGE_SIZE;
1154 shadow_sgt:
1155 		rtte.fc0.p |= *dat_protection;
1156 		rc = gmap_shadow_sgt(sg, saddr, rtte.val, *fake);
1157 		if (rc)
1158 			return rc;
1159 	}
1160 		fallthrough;
1161 	case ASCE_TYPE_SEGMENT: {
1162 		union segment_table_entry ste;
1163 
1164 		if (*fake) {
1165 			ptr += vaddr.sx * _SEGMENT_SIZE;
1166 			ste.val = ptr;
1167 			goto shadow_pgt;
1168 		}
1169 		*pgt = ptr + vaddr.sx * 8;
1170 		rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val);
1171 		if (rc)
1172 			return rc;
1173 		if (ste.i)
1174 			return PGM_SEGMENT_TRANSLATION;
1175 		if (ste.tt != TABLE_TYPE_SEGMENT)
1176 			return PGM_TRANSLATION_SPEC;
1177 		if (ste.cs && asce.p)
1178 			return PGM_TRANSLATION_SPEC;
1179 		*dat_protection |= ste.fc0.p;
1180 		if (ste.fc && sg->edat_level >= 1) {
1181 			*fake = 1;
1182 			ptr = ste.fc1.sfaa * _SEGMENT_SIZE;
1183 			ste.val = ptr;
1184 			goto shadow_pgt;
1185 		}
1186 		ptr = ste.fc0.pto * (PAGE_SIZE / 2);
1187 shadow_pgt:
1188 		ste.fc0.p |= *dat_protection;
1189 		rc = gmap_shadow_pgt(sg, saddr, ste.val, *fake);
1190 		if (rc)
1191 			return rc;
1192 	}
1193 	}
1194 	/* Return the parent address of the page table */
1195 	*pgt = ptr;
1196 	return 0;
1197 }
1198 
1199 /**
1200  * kvm_s390_shadow_fault - handle fault on a shadow page table
1201  * @vcpu: virtual cpu
1202  * @sg: pointer to the shadow guest address space structure
1203  * @saddr: faulting address in the shadow gmap
1204  * @datptr: will contain the address of the faulting DAT table entry, or of
1205  *	    the valid leaf, plus some flags
1206  *
1207  * Returns: - 0 if the shadow fault was successfully resolved
1208  *	    - > 0 (pgm exception code) on exceptions while faulting
1209  *	    - -EAGAIN if the caller can retry immediately
1210  *	    - -EFAULT when accessing invalid guest addresses
1211  *	    - -ENOMEM if out of memory
1212  */
1213 int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
1214 			  unsigned long saddr, unsigned long *datptr)
1215 {
1216 	union vaddress vaddr;
1217 	union page_table_entry pte;
1218 	unsigned long pgt = 0;
1219 	int dat_protection, fake;
1220 	int rc;
1221 
1222 	mmap_read_lock(sg->mm);
1223 	/*
1224 	 * We don't want any guest-2 tables to change - so the parent
1225 	 * tables/pointers we read stay valid - unshadowing is however
1226 	 * always possible - only guest_table_lock protects us.
1227 	 */
1228 	ipte_lock(vcpu);
1229 
1230 	rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
1231 	if (rc)
1232 		rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection,
1233 					    &fake);
1234 
1235 	vaddr.addr = saddr;
1236 	if (fake) {
1237 		pte.val = pgt + vaddr.px * PAGE_SIZE;
1238 		goto shadow_page;
1239 	}
1240 
1241 	switch (rc) {
1242 	case PGM_SEGMENT_TRANSLATION:
1243 	case PGM_REGION_THIRD_TRANS:
1244 	case PGM_REGION_SECOND_TRANS:
1245 	case PGM_REGION_FIRST_TRANS:
1246 		pgt |= PEI_NOT_PTE;
1247 		break;
1248 	case 0:
1249 		pgt += vaddr.px * 8;
1250 		rc = gmap_read_table(sg->parent, pgt, &pte.val);
1251 	}
1252 	if (datptr)
1253 		*datptr = pgt | dat_protection * PEI_DAT_PROT;
1254 	if (!rc && pte.i)
1255 		rc = PGM_PAGE_TRANSLATION;
1256 	if (!rc && pte.z)
1257 		rc = PGM_TRANSLATION_SPEC;
1258 shadow_page:
1259 	pte.p |= dat_protection;
1260 	if (!rc)
1261 		rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
1262 	ipte_unlock(vcpu);
1263 	mmap_read_unlock(sg->mm);
1264 	return rc;
1265 }
1266