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1 /*
2  * guest access functions
3  *
4  * Copyright IBM Corp. 2014
5  *
6  */
7 
8 #include <linux/vmalloc.h>
9 #include <linux/err.h>
10 #include <asm/pgtable.h>
11 #include "kvm-s390.h"
12 #include "gaccess.h"
13 #include <asm/switch_to.h>
14 
15 union asce {
16 	unsigned long val;
17 	struct {
18 		unsigned long origin : 52; /* Region- or Segment-Table Origin */
19 		unsigned long	 : 2;
20 		unsigned long g  : 1; /* Subspace Group Control */
21 		unsigned long p  : 1; /* Private Space Control */
22 		unsigned long s  : 1; /* Storage-Alteration-Event Control */
23 		unsigned long x  : 1; /* Space-Switch-Event Control */
24 		unsigned long r  : 1; /* Real-Space Control */
25 		unsigned long	 : 1;
26 		unsigned long dt : 2; /* Designation-Type Control */
27 		unsigned long tl : 2; /* Region- or Segment-Table Length */
28 	};
29 };
30 
31 enum {
32 	ASCE_TYPE_SEGMENT = 0,
33 	ASCE_TYPE_REGION3 = 1,
34 	ASCE_TYPE_REGION2 = 2,
35 	ASCE_TYPE_REGION1 = 3
36 };
37 
38 union region1_table_entry {
39 	unsigned long val;
40 	struct {
41 		unsigned long rto: 52;/* Region-Table Origin */
42 		unsigned long	 : 2;
43 		unsigned long p  : 1; /* DAT-Protection Bit */
44 		unsigned long	 : 1;
45 		unsigned long tf : 2; /* Region-Second-Table Offset */
46 		unsigned long i  : 1; /* Region-Invalid Bit */
47 		unsigned long	 : 1;
48 		unsigned long tt : 2; /* Table-Type Bits */
49 		unsigned long tl : 2; /* Region-Second-Table Length */
50 	};
51 };
52 
53 union region2_table_entry {
54 	unsigned long val;
55 	struct {
56 		unsigned long rto: 52;/* Region-Table Origin */
57 		unsigned long	 : 2;
58 		unsigned long p  : 1; /* DAT-Protection Bit */
59 		unsigned long	 : 1;
60 		unsigned long tf : 2; /* Region-Third-Table Offset */
61 		unsigned long i  : 1; /* Region-Invalid Bit */
62 		unsigned long	 : 1;
63 		unsigned long tt : 2; /* Table-Type Bits */
64 		unsigned long tl : 2; /* Region-Third-Table Length */
65 	};
66 };
67 
68 struct region3_table_entry_fc0 {
69 	unsigned long sto: 52;/* Segment-Table Origin */
70 	unsigned long	 : 1;
71 	unsigned long fc : 1; /* Format-Control */
72 	unsigned long p  : 1; /* DAT-Protection Bit */
73 	unsigned long	 : 1;
74 	unsigned long tf : 2; /* Segment-Table Offset */
75 	unsigned long i  : 1; /* Region-Invalid Bit */
76 	unsigned long cr : 1; /* Common-Region Bit */
77 	unsigned long tt : 2; /* Table-Type Bits */
78 	unsigned long tl : 2; /* Segment-Table Length */
79 };
80 
81 struct region3_table_entry_fc1 {
82 	unsigned long rfaa : 33; /* Region-Frame Absolute Address */
83 	unsigned long	 : 14;
84 	unsigned long av : 1; /* ACCF-Validity Control */
85 	unsigned long acc: 4; /* Access-Control Bits */
86 	unsigned long f  : 1; /* Fetch-Protection Bit */
87 	unsigned long fc : 1; /* Format-Control */
88 	unsigned long p  : 1; /* DAT-Protection Bit */
89 	unsigned long co : 1; /* Change-Recording Override */
90 	unsigned long	 : 2;
91 	unsigned long i  : 1; /* Region-Invalid Bit */
92 	unsigned long cr : 1; /* Common-Region Bit */
93 	unsigned long tt : 2; /* Table-Type Bits */
94 	unsigned long	 : 2;
95 };
96 
97 union region3_table_entry {
98 	unsigned long val;
99 	struct region3_table_entry_fc0 fc0;
100 	struct region3_table_entry_fc1 fc1;
101 	struct {
102 		unsigned long	 : 53;
103 		unsigned long fc : 1; /* Format-Control */
104 		unsigned long	 : 4;
105 		unsigned long i  : 1; /* Region-Invalid Bit */
106 		unsigned long cr : 1; /* Common-Region Bit */
107 		unsigned long tt : 2; /* Table-Type Bits */
108 		unsigned long	 : 2;
109 	};
110 };
111 
112 struct segment_entry_fc0 {
113 	unsigned long pto: 53;/* Page-Table Origin */
114 	unsigned long fc : 1; /* Format-Control */
115 	unsigned long p  : 1; /* DAT-Protection Bit */
116 	unsigned long	 : 3;
117 	unsigned long i  : 1; /* Segment-Invalid Bit */
118 	unsigned long cs : 1; /* Common-Segment Bit */
119 	unsigned long tt : 2; /* Table-Type Bits */
120 	unsigned long	 : 2;
121 };
122 
123 struct segment_entry_fc1 {
124 	unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
125 	unsigned long	 : 3;
126 	unsigned long av : 1; /* ACCF-Validity Control */
127 	unsigned long acc: 4; /* Access-Control Bits */
128 	unsigned long f  : 1; /* Fetch-Protection Bit */
129 	unsigned long fc : 1; /* Format-Control */
130 	unsigned long p  : 1; /* DAT-Protection Bit */
131 	unsigned long co : 1; /* Change-Recording Override */
132 	unsigned long	 : 2;
133 	unsigned long i  : 1; /* Segment-Invalid Bit */
134 	unsigned long cs : 1; /* Common-Segment Bit */
135 	unsigned long tt : 2; /* Table-Type Bits */
136 	unsigned long	 : 2;
137 };
138 
139 union segment_table_entry {
140 	unsigned long val;
141 	struct segment_entry_fc0 fc0;
142 	struct segment_entry_fc1 fc1;
143 	struct {
144 		unsigned long	 : 53;
145 		unsigned long fc : 1; /* Format-Control */
146 		unsigned long	 : 4;
147 		unsigned long i  : 1; /* Segment-Invalid Bit */
148 		unsigned long cs : 1; /* Common-Segment Bit */
149 		unsigned long tt : 2; /* Table-Type Bits */
150 		unsigned long	 : 2;
151 	};
152 };
153 
154 enum {
155 	TABLE_TYPE_SEGMENT = 0,
156 	TABLE_TYPE_REGION3 = 1,
157 	TABLE_TYPE_REGION2 = 2,
158 	TABLE_TYPE_REGION1 = 3
159 };
160 
161 union page_table_entry {
162 	unsigned long val;
163 	struct {
164 		unsigned long pfra : 52; /* Page-Frame Real Address */
165 		unsigned long z  : 1; /* Zero Bit */
166 		unsigned long i  : 1; /* Page-Invalid Bit */
167 		unsigned long p  : 1; /* DAT-Protection Bit */
168 		unsigned long co : 1; /* Change-Recording Override */
169 		unsigned long	 : 8;
170 	};
171 };
172 
173 /*
174  * vaddress union in order to easily decode a virtual address into its
175  * region first index, region second index etc. parts.
176  */
177 union vaddress {
178 	unsigned long addr;
179 	struct {
180 		unsigned long rfx : 11;
181 		unsigned long rsx : 11;
182 		unsigned long rtx : 11;
183 		unsigned long sx  : 11;
184 		unsigned long px  : 8;
185 		unsigned long bx  : 12;
186 	};
187 	struct {
188 		unsigned long rfx01 : 2;
189 		unsigned long	    : 9;
190 		unsigned long rsx01 : 2;
191 		unsigned long	    : 9;
192 		unsigned long rtx01 : 2;
193 		unsigned long	    : 9;
194 		unsigned long sx01  : 2;
195 		unsigned long	    : 29;
196 	};
197 };
198 
199 /*
200  * raddress union which will contain the result (real or absolute address)
201  * after a page table walk. The rfaa, sfaa and pfra members are used to
202  * simply assign them the value of a region, segment or page table entry.
203  */
204 union raddress {
205 	unsigned long addr;
206 	unsigned long rfaa : 33; /* Region-Frame Absolute Address */
207 	unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
208 	unsigned long pfra : 52; /* Page-Frame Real Address */
209 };
210 
211 union alet {
212 	u32 val;
213 	struct {
214 		u32 reserved : 7;
215 		u32 p        : 1;
216 		u32 alesn    : 8;
217 		u32 alen     : 16;
218 	};
219 };
220 
221 union ald {
222 	u32 val;
223 	struct {
224 		u32     : 1;
225 		u32 alo : 24;
226 		u32 all : 7;
227 	};
228 };
229 
230 struct ale {
231 	unsigned long i      : 1; /* ALEN-Invalid Bit */
232 	unsigned long        : 5;
233 	unsigned long fo     : 1; /* Fetch-Only Bit */
234 	unsigned long p      : 1; /* Private Bit */
235 	unsigned long alesn  : 8; /* Access-List-Entry Sequence Number */
236 	unsigned long aleax  : 16; /* Access-List-Entry Authorization Index */
237 	unsigned long        : 32;
238 	unsigned long        : 1;
239 	unsigned long asteo  : 25; /* ASN-Second-Table-Entry Origin */
240 	unsigned long        : 6;
241 	unsigned long astesn : 32; /* ASTE Sequence Number */
242 } __packed;
243 
244 struct aste {
245 	unsigned long i      : 1; /* ASX-Invalid Bit */
246 	unsigned long ato    : 29; /* Authority-Table Origin */
247 	unsigned long        : 1;
248 	unsigned long b      : 1; /* Base-Space Bit */
249 	unsigned long ax     : 16; /* Authorization Index */
250 	unsigned long atl    : 12; /* Authority-Table Length */
251 	unsigned long        : 2;
252 	unsigned long ca     : 1; /* Controlled-ASN Bit */
253 	unsigned long ra     : 1; /* Reusable-ASN Bit */
254 	unsigned long asce   : 64; /* Address-Space-Control Element */
255 	unsigned long ald    : 32;
256 	unsigned long astesn : 32;
257 	/* .. more fields there */
258 } __packed;
259 
ipte_lock_held(struct kvm_vcpu * vcpu)260 int ipte_lock_held(struct kvm_vcpu *vcpu)
261 {
262 	union ipte_control *ic = &vcpu->kvm->arch.sca->ipte_control;
263 
264 	if (vcpu->arch.sie_block->eca & 1)
265 		return ic->kh != 0;
266 	return vcpu->kvm->arch.ipte_lock_count != 0;
267 }
268 
ipte_lock_simple(struct kvm_vcpu * vcpu)269 static void ipte_lock_simple(struct kvm_vcpu *vcpu)
270 {
271 	union ipte_control old, new, *ic;
272 
273 	mutex_lock(&vcpu->kvm->arch.ipte_mutex);
274 	vcpu->kvm->arch.ipte_lock_count++;
275 	if (vcpu->kvm->arch.ipte_lock_count > 1)
276 		goto out;
277 	ic = &vcpu->kvm->arch.sca->ipte_control;
278 	do {
279 		old = READ_ONCE(*ic);
280 		while (old.k) {
281 			cond_resched();
282 			old = READ_ONCE(*ic);
283 		}
284 		new = old;
285 		new.k = 1;
286 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
287 out:
288 	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
289 }
290 
ipte_unlock_simple(struct kvm_vcpu * vcpu)291 static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
292 {
293 	union ipte_control old, new, *ic;
294 
295 	mutex_lock(&vcpu->kvm->arch.ipte_mutex);
296 	vcpu->kvm->arch.ipte_lock_count--;
297 	if (vcpu->kvm->arch.ipte_lock_count)
298 		goto out;
299 	ic = &vcpu->kvm->arch.sca->ipte_control;
300 	do {
301 		old = READ_ONCE(*ic);
302 		new = old;
303 		new.k = 0;
304 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
305 	wake_up(&vcpu->kvm->arch.ipte_wq);
306 out:
307 	mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
308 }
309 
ipte_lock_siif(struct kvm_vcpu * vcpu)310 static void ipte_lock_siif(struct kvm_vcpu *vcpu)
311 {
312 	union ipte_control old, new, *ic;
313 
314 	ic = &vcpu->kvm->arch.sca->ipte_control;
315 	do {
316 		old = READ_ONCE(*ic);
317 		while (old.kg) {
318 			cond_resched();
319 			old = READ_ONCE(*ic);
320 		}
321 		new = old;
322 		new.k = 1;
323 		new.kh++;
324 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
325 }
326 
ipte_unlock_siif(struct kvm_vcpu * vcpu)327 static void ipte_unlock_siif(struct kvm_vcpu *vcpu)
328 {
329 	union ipte_control old, new, *ic;
330 
331 	ic = &vcpu->kvm->arch.sca->ipte_control;
332 	do {
333 		old = READ_ONCE(*ic);
334 		new = old;
335 		new.kh--;
336 		if (!new.kh)
337 			new.k = 0;
338 	} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
339 	if (!new.kh)
340 		wake_up(&vcpu->kvm->arch.ipte_wq);
341 }
342 
ipte_lock(struct kvm_vcpu * vcpu)343 void ipte_lock(struct kvm_vcpu *vcpu)
344 {
345 	if (vcpu->arch.sie_block->eca & 1)
346 		ipte_lock_siif(vcpu);
347 	else
348 		ipte_lock_simple(vcpu);
349 }
350 
ipte_unlock(struct kvm_vcpu * vcpu)351 void ipte_unlock(struct kvm_vcpu *vcpu)
352 {
353 	if (vcpu->arch.sie_block->eca & 1)
354 		ipte_unlock_siif(vcpu);
355 	else
356 		ipte_unlock_simple(vcpu);
357 }
358 
ar_translation(struct kvm_vcpu * vcpu,union asce * asce,ar_t ar,int write)359 static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, ar_t ar,
360 			  int write)
361 {
362 	union alet alet;
363 	struct ale ale;
364 	struct aste aste;
365 	unsigned long ald_addr, authority_table_addr;
366 	union ald ald;
367 	int eax, rc;
368 	u8 authority_table;
369 
370 	if (ar >= NUM_ACRS)
371 		return -EINVAL;
372 
373 	save_access_regs(vcpu->run->s.regs.acrs);
374 	alet.val = vcpu->run->s.regs.acrs[ar];
375 
376 	if (ar == 0 || alet.val == 0) {
377 		asce->val = vcpu->arch.sie_block->gcr[1];
378 		return 0;
379 	} else if (alet.val == 1) {
380 		asce->val = vcpu->arch.sie_block->gcr[7];
381 		return 0;
382 	}
383 
384 	if (alet.reserved)
385 		return PGM_ALET_SPECIFICATION;
386 
387 	if (alet.p)
388 		ald_addr = vcpu->arch.sie_block->gcr[5];
389 	else
390 		ald_addr = vcpu->arch.sie_block->gcr[2];
391 	ald_addr &= 0x7fffffc0;
392 
393 	rc = read_guest_real(vcpu, ald_addr + 16, &ald.val, sizeof(union ald));
394 	if (rc)
395 		return rc;
396 
397 	if (alet.alen / 8 > ald.all)
398 		return PGM_ALEN_TRANSLATION;
399 
400 	if (0x7fffffff - ald.alo * 128 < alet.alen * 16)
401 		return PGM_ADDRESSING;
402 
403 	rc = read_guest_real(vcpu, ald.alo * 128 + alet.alen * 16, &ale,
404 			     sizeof(struct ale));
405 	if (rc)
406 		return rc;
407 
408 	if (ale.i == 1)
409 		return PGM_ALEN_TRANSLATION;
410 	if (ale.alesn != alet.alesn)
411 		return PGM_ALE_SEQUENCE;
412 
413 	rc = read_guest_real(vcpu, ale.asteo * 64, &aste, sizeof(struct aste));
414 	if (rc)
415 		return rc;
416 
417 	if (aste.i)
418 		return PGM_ASTE_VALIDITY;
419 	if (aste.astesn != ale.astesn)
420 		return PGM_ASTE_SEQUENCE;
421 
422 	if (ale.p == 1) {
423 		eax = (vcpu->arch.sie_block->gcr[8] >> 16) & 0xffff;
424 		if (ale.aleax != eax) {
425 			if (eax / 16 > aste.atl)
426 				return PGM_EXTENDED_AUTHORITY;
427 
428 			authority_table_addr = aste.ato * 4 + eax / 4;
429 
430 			rc = read_guest_real(vcpu, authority_table_addr,
431 					     &authority_table,
432 					     sizeof(u8));
433 			if (rc)
434 				return rc;
435 
436 			if ((authority_table & (0x40 >> ((eax & 3) * 2))) == 0)
437 				return PGM_EXTENDED_AUTHORITY;
438 		}
439 	}
440 
441 	if (ale.fo == 1 && write)
442 		return PGM_PROTECTION;
443 
444 	asce->val = aste.asce;
445 	return 0;
446 }
447 
448 struct trans_exc_code_bits {
449 	unsigned long addr : 52; /* Translation-exception Address */
450 	unsigned long fsi  : 2;  /* Access Exception Fetch/Store Indication */
451 	unsigned long	   : 6;
452 	unsigned long b60  : 1;
453 	unsigned long b61  : 1;
454 	unsigned long as   : 2;  /* ASCE Identifier */
455 };
456 
457 enum {
458 	FSI_UNKNOWN = 0, /* Unknown wether fetch or store */
459 	FSI_STORE   = 1, /* Exception was due to store operation */
460 	FSI_FETCH   = 2  /* Exception was due to fetch operation */
461 };
462 
get_vcpu_asce(struct kvm_vcpu * vcpu,union asce * asce,ar_t ar,int write)463 static int get_vcpu_asce(struct kvm_vcpu *vcpu, union asce *asce,
464 			 ar_t ar, int write)
465 {
466 	int rc;
467 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
468 	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
469 	struct trans_exc_code_bits *tec_bits;
470 
471 	memset(pgm, 0, sizeof(*pgm));
472 	tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
473 	tec_bits->fsi = write ? FSI_STORE : FSI_FETCH;
474 	tec_bits->as = psw_bits(*psw).as;
475 
476 	if (!psw_bits(*psw).t) {
477 		asce->val = 0;
478 		asce->r = 1;
479 		return 0;
480 	}
481 
482 	switch (psw_bits(vcpu->arch.sie_block->gpsw).as) {
483 	case PSW_AS_PRIMARY:
484 		asce->val = vcpu->arch.sie_block->gcr[1];
485 		return 0;
486 	case PSW_AS_SECONDARY:
487 		asce->val = vcpu->arch.sie_block->gcr[7];
488 		return 0;
489 	case PSW_AS_HOME:
490 		asce->val = vcpu->arch.sie_block->gcr[13];
491 		return 0;
492 	case PSW_AS_ACCREG:
493 		rc = ar_translation(vcpu, asce, ar, write);
494 		switch (rc) {
495 		case PGM_ALEN_TRANSLATION:
496 		case PGM_ALE_SEQUENCE:
497 		case PGM_ASTE_VALIDITY:
498 		case PGM_ASTE_SEQUENCE:
499 		case PGM_EXTENDED_AUTHORITY:
500 			vcpu->arch.pgm.exc_access_id = ar;
501 			break;
502 		case PGM_PROTECTION:
503 			tec_bits->b60 = 1;
504 			tec_bits->b61 = 1;
505 			break;
506 		}
507 		if (rc > 0)
508 			pgm->code = rc;
509 		return rc;
510 	}
511 	return 0;
512 }
513 
deref_table(struct kvm * kvm,unsigned long gpa,unsigned long * val)514 static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val)
515 {
516 	return kvm_read_guest(kvm, gpa, val, sizeof(*val));
517 }
518 
519 /**
520  * guest_translate - translate a guest virtual into a guest absolute address
521  * @vcpu: virtual cpu
522  * @gva: guest virtual address
523  * @gpa: points to where guest physical (absolute) address should be stored
524  * @asce: effective asce
525  * @write: indicates if access is a write access
526  *
527  * Translate a guest virtual address into a guest absolute address by means
528  * of dynamic address translation as specified by the architecture.
529  * If the resulting absolute address is not available in the configuration
530  * an addressing exception is indicated and @gpa will not be changed.
531  *
532  * Returns: - zero on success; @gpa contains the resulting absolute address
533  *	    - a negative value if guest access failed due to e.g. broken
534  *	      guest mapping
535  *	    - a positve value if an access exception happened. In this case
536  *	      the returned value is the program interruption code as defined
537  *	      by the architecture
538  */
guest_translate(struct kvm_vcpu * vcpu,unsigned long gva,unsigned long * gpa,const union asce asce,int write)539 static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
540 				     unsigned long *gpa, const union asce asce,
541 				     int write)
542 {
543 	union vaddress vaddr = {.addr = gva};
544 	union raddress raddr = {.addr = gva};
545 	union page_table_entry pte;
546 	int dat_protection = 0;
547 	union ctlreg0 ctlreg0;
548 	unsigned long ptr;
549 	int edat1, edat2;
550 
551 	ctlreg0.val = vcpu->arch.sie_block->gcr[0];
552 	edat1 = ctlreg0.edat && test_kvm_facility(vcpu->kvm, 8);
553 	edat2 = edat1 && test_kvm_facility(vcpu->kvm, 78);
554 	if (asce.r)
555 		goto real_address;
556 	ptr = asce.origin * 4096;
557 	switch (asce.dt) {
558 	case ASCE_TYPE_REGION1:
559 		if (vaddr.rfx01 > asce.tl)
560 			return PGM_REGION_FIRST_TRANS;
561 		ptr += vaddr.rfx * 8;
562 		break;
563 	case ASCE_TYPE_REGION2:
564 		if (vaddr.rfx)
565 			return PGM_ASCE_TYPE;
566 		if (vaddr.rsx01 > asce.tl)
567 			return PGM_REGION_SECOND_TRANS;
568 		ptr += vaddr.rsx * 8;
569 		break;
570 	case ASCE_TYPE_REGION3:
571 		if (vaddr.rfx || vaddr.rsx)
572 			return PGM_ASCE_TYPE;
573 		if (vaddr.rtx01 > asce.tl)
574 			return PGM_REGION_THIRD_TRANS;
575 		ptr += vaddr.rtx * 8;
576 		break;
577 	case ASCE_TYPE_SEGMENT:
578 		if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
579 			return PGM_ASCE_TYPE;
580 		if (vaddr.sx01 > asce.tl)
581 			return PGM_SEGMENT_TRANSLATION;
582 		ptr += vaddr.sx * 8;
583 		break;
584 	}
585 	switch (asce.dt) {
586 	case ASCE_TYPE_REGION1:	{
587 		union region1_table_entry rfte;
588 
589 		if (kvm_is_error_gpa(vcpu->kvm, ptr))
590 			return PGM_ADDRESSING;
591 		if (deref_table(vcpu->kvm, ptr, &rfte.val))
592 			return -EFAULT;
593 		if (rfte.i)
594 			return PGM_REGION_FIRST_TRANS;
595 		if (rfte.tt != TABLE_TYPE_REGION1)
596 			return PGM_TRANSLATION_SPEC;
597 		if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
598 			return PGM_REGION_SECOND_TRANS;
599 		if (edat1)
600 			dat_protection |= rfte.p;
601 		ptr = rfte.rto * 4096 + vaddr.rsx * 8;
602 	}
603 		/* fallthrough */
604 	case ASCE_TYPE_REGION2: {
605 		union region2_table_entry rste;
606 
607 		if (kvm_is_error_gpa(vcpu->kvm, ptr))
608 			return PGM_ADDRESSING;
609 		if (deref_table(vcpu->kvm, ptr, &rste.val))
610 			return -EFAULT;
611 		if (rste.i)
612 			return PGM_REGION_SECOND_TRANS;
613 		if (rste.tt != TABLE_TYPE_REGION2)
614 			return PGM_TRANSLATION_SPEC;
615 		if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
616 			return PGM_REGION_THIRD_TRANS;
617 		if (edat1)
618 			dat_protection |= rste.p;
619 		ptr = rste.rto * 4096 + vaddr.rtx * 8;
620 	}
621 		/* fallthrough */
622 	case ASCE_TYPE_REGION3: {
623 		union region3_table_entry rtte;
624 
625 		if (kvm_is_error_gpa(vcpu->kvm, ptr))
626 			return PGM_ADDRESSING;
627 		if (deref_table(vcpu->kvm, ptr, &rtte.val))
628 			return -EFAULT;
629 		if (rtte.i)
630 			return PGM_REGION_THIRD_TRANS;
631 		if (rtte.tt != TABLE_TYPE_REGION3)
632 			return PGM_TRANSLATION_SPEC;
633 		if (rtte.cr && asce.p && edat2)
634 			return PGM_TRANSLATION_SPEC;
635 		if (rtte.fc && edat2) {
636 			dat_protection |= rtte.fc1.p;
637 			raddr.rfaa = rtte.fc1.rfaa;
638 			goto absolute_address;
639 		}
640 		if (vaddr.sx01 < rtte.fc0.tf)
641 			return PGM_SEGMENT_TRANSLATION;
642 		if (vaddr.sx01 > rtte.fc0.tl)
643 			return PGM_SEGMENT_TRANSLATION;
644 		if (edat1)
645 			dat_protection |= rtte.fc0.p;
646 		ptr = rtte.fc0.sto * 4096 + vaddr.sx * 8;
647 	}
648 		/* fallthrough */
649 	case ASCE_TYPE_SEGMENT: {
650 		union segment_table_entry ste;
651 
652 		if (kvm_is_error_gpa(vcpu->kvm, ptr))
653 			return PGM_ADDRESSING;
654 		if (deref_table(vcpu->kvm, ptr, &ste.val))
655 			return -EFAULT;
656 		if (ste.i)
657 			return PGM_SEGMENT_TRANSLATION;
658 		if (ste.tt != TABLE_TYPE_SEGMENT)
659 			return PGM_TRANSLATION_SPEC;
660 		if (ste.cs && asce.p)
661 			return PGM_TRANSLATION_SPEC;
662 		if (ste.fc && edat1) {
663 			dat_protection |= ste.fc1.p;
664 			raddr.sfaa = ste.fc1.sfaa;
665 			goto absolute_address;
666 		}
667 		dat_protection |= ste.fc0.p;
668 		ptr = ste.fc0.pto * 2048 + vaddr.px * 8;
669 	}
670 	}
671 	if (kvm_is_error_gpa(vcpu->kvm, ptr))
672 		return PGM_ADDRESSING;
673 	if (deref_table(vcpu->kvm, ptr, &pte.val))
674 		return -EFAULT;
675 	if (pte.i)
676 		return PGM_PAGE_TRANSLATION;
677 	if (pte.z)
678 		return PGM_TRANSLATION_SPEC;
679 	if (pte.co && !edat1)
680 		return PGM_TRANSLATION_SPEC;
681 	dat_protection |= pte.p;
682 	raddr.pfra = pte.pfra;
683 real_address:
684 	raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr);
685 absolute_address:
686 	if (write && dat_protection)
687 		return PGM_PROTECTION;
688 	if (kvm_is_error_gpa(vcpu->kvm, raddr.addr))
689 		return PGM_ADDRESSING;
690 	*gpa = raddr.addr;
691 	return 0;
692 }
693 
is_low_address(unsigned long ga)694 static inline int is_low_address(unsigned long ga)
695 {
696 	/* Check for address ranges 0..511 and 4096..4607 */
697 	return (ga & ~0x11fful) == 0;
698 }
699 
low_address_protection_enabled(struct kvm_vcpu * vcpu,const union asce asce)700 static int low_address_protection_enabled(struct kvm_vcpu *vcpu,
701 					  const union asce asce)
702 {
703 	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
704 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
705 
706 	if (!ctlreg0.lap)
707 		return 0;
708 	if (psw_bits(*psw).t && asce.p)
709 		return 0;
710 	return 1;
711 }
712 
guest_page_range(struct kvm_vcpu * vcpu,unsigned long ga,unsigned long * pages,unsigned long nr_pages,const union asce asce,int write)713 static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga,
714 			    unsigned long *pages, unsigned long nr_pages,
715 			    const union asce asce, int write)
716 {
717 	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
718 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
719 	struct trans_exc_code_bits *tec_bits;
720 	int lap_enabled, rc;
721 
722 	tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
723 	lap_enabled = low_address_protection_enabled(vcpu, asce);
724 	while (nr_pages) {
725 		ga = kvm_s390_logical_to_effective(vcpu, ga);
726 		tec_bits->addr = ga >> PAGE_SHIFT;
727 		if (write && lap_enabled && is_low_address(ga)) {
728 			pgm->code = PGM_PROTECTION;
729 			return pgm->code;
730 		}
731 		ga &= PAGE_MASK;
732 		if (psw_bits(*psw).t) {
733 			rc = guest_translate(vcpu, ga, pages, asce, write);
734 			if (rc < 0)
735 				return rc;
736 			if (rc == PGM_PROTECTION)
737 				tec_bits->b61 = 1;
738 			if (rc)
739 				pgm->code = rc;
740 		} else {
741 			*pages = kvm_s390_real_to_abs(vcpu, ga);
742 			if (kvm_is_error_gpa(vcpu->kvm, *pages))
743 				pgm->code = PGM_ADDRESSING;
744 		}
745 		if (pgm->code)
746 			return pgm->code;
747 		ga += PAGE_SIZE;
748 		pages++;
749 		nr_pages--;
750 	}
751 	return 0;
752 }
753 
access_guest(struct kvm_vcpu * vcpu,unsigned long ga,ar_t ar,void * data,unsigned long len,int write)754 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, ar_t ar, void *data,
755 		 unsigned long len, int write)
756 {
757 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
758 	unsigned long _len, nr_pages, gpa, idx;
759 	unsigned long pages_array[2];
760 	unsigned long *pages;
761 	int need_ipte_lock;
762 	union asce asce;
763 	int rc;
764 
765 	if (!len)
766 		return 0;
767 	rc = get_vcpu_asce(vcpu, &asce, ar, write);
768 	if (rc)
769 		return rc;
770 	nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1;
771 	pages = pages_array;
772 	if (nr_pages > ARRAY_SIZE(pages_array))
773 		pages = vmalloc(nr_pages * sizeof(unsigned long));
774 	if (!pages)
775 		return -ENOMEM;
776 	need_ipte_lock = psw_bits(*psw).t && !asce.r;
777 	if (need_ipte_lock)
778 		ipte_lock(vcpu);
779 	rc = guest_page_range(vcpu, ga, pages, nr_pages, asce, write);
780 	for (idx = 0; idx < nr_pages && !rc; idx++) {
781 		gpa = *(pages + idx) + (ga & ~PAGE_MASK);
782 		_len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
783 		if (write)
784 			rc = kvm_write_guest(vcpu->kvm, gpa, data, _len);
785 		else
786 			rc = kvm_read_guest(vcpu->kvm, gpa, data, _len);
787 		len -= _len;
788 		ga += _len;
789 		data += _len;
790 	}
791 	if (need_ipte_lock)
792 		ipte_unlock(vcpu);
793 	if (nr_pages > ARRAY_SIZE(pages_array))
794 		vfree(pages);
795 	return rc;
796 }
797 
access_guest_real(struct kvm_vcpu * vcpu,unsigned long gra,void * data,unsigned long len,int write)798 int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
799 		      void *data, unsigned long len, int write)
800 {
801 	unsigned long _len, gpa;
802 	int rc = 0;
803 
804 	while (len && !rc) {
805 		gpa = kvm_s390_real_to_abs(vcpu, gra);
806 		_len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
807 		if (write)
808 			rc = write_guest_abs(vcpu, gpa, data, _len);
809 		else
810 			rc = read_guest_abs(vcpu, gpa, data, _len);
811 		len -= _len;
812 		gra += _len;
813 		data += _len;
814 	}
815 	return rc;
816 }
817 
818 /**
819  * guest_translate_address - translate guest logical into guest absolute address
820  *
821  * Parameter semantics are the same as the ones from guest_translate.
822  * The memory contents at the guest address are not changed.
823  *
824  * Note: The IPTE lock is not taken during this function, so the caller
825  * has to take care of this.
826  */
guest_translate_address(struct kvm_vcpu * vcpu,unsigned long gva,ar_t ar,unsigned long * gpa,int write)827 int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar,
828 			    unsigned long *gpa, int write)
829 {
830 	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
831 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
832 	struct trans_exc_code_bits *tec;
833 	union asce asce;
834 	int rc;
835 
836 	gva = kvm_s390_logical_to_effective(vcpu, gva);
837 	tec = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
838 	rc = get_vcpu_asce(vcpu, &asce, ar, write);
839 	tec->addr = gva >> PAGE_SHIFT;
840 	if (rc)
841 		return rc;
842 	if (is_low_address(gva) && low_address_protection_enabled(vcpu, asce)) {
843 		if (write) {
844 			rc = pgm->code = PGM_PROTECTION;
845 			return rc;
846 		}
847 	}
848 
849 	if (psw_bits(*psw).t && !asce.r) {	/* Use DAT? */
850 		rc = guest_translate(vcpu, gva, gpa, asce, write);
851 		if (rc > 0) {
852 			if (rc == PGM_PROTECTION)
853 				tec->b61 = 1;
854 			pgm->code = rc;
855 		}
856 	} else {
857 		rc = 0;
858 		*gpa = kvm_s390_real_to_abs(vcpu, gva);
859 		if (kvm_is_error_gpa(vcpu->kvm, *gpa))
860 			rc = pgm->code = PGM_ADDRESSING;
861 	}
862 
863 	return rc;
864 }
865 
866 /**
867  * check_gva_range - test a range of guest virtual addresses for accessibility
868  */
check_gva_range(struct kvm_vcpu * vcpu,unsigned long gva,ar_t ar,unsigned long length,int is_write)869 int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar,
870 		    unsigned long length, int is_write)
871 {
872 	unsigned long gpa;
873 	unsigned long currlen;
874 	int rc = 0;
875 
876 	ipte_lock(vcpu);
877 	while (length > 0 && !rc) {
878 		currlen = min(length, PAGE_SIZE - (gva % PAGE_SIZE));
879 		rc = guest_translate_address(vcpu, gva, ar, &gpa, is_write);
880 		gva += currlen;
881 		length -= currlen;
882 	}
883 	ipte_unlock(vcpu);
884 
885 	return rc;
886 }
887 
888 /**
889  * kvm_s390_check_low_addr_prot_real - check for low-address protection
890  * @gra: Guest real address
891  *
892  * Checks whether an address is subject to low-address protection and set
893  * up vcpu->arch.pgm accordingly if necessary.
894  *
895  * Return: 0 if no protection exception, or PGM_PROTECTION if protected.
896  */
kvm_s390_check_low_addr_prot_real(struct kvm_vcpu * vcpu,unsigned long gra)897 int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra)
898 {
899 	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
900 	psw_t *psw = &vcpu->arch.sie_block->gpsw;
901 	struct trans_exc_code_bits *tec_bits;
902 	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
903 
904 	if (!ctlreg0.lap || !is_low_address(gra))
905 		return 0;
906 
907 	memset(pgm, 0, sizeof(*pgm));
908 	tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
909 	tec_bits->fsi = FSI_STORE;
910 	tec_bits->as = psw_bits(*psw).as;
911 	tec_bits->addr = gra >> PAGE_SHIFT;
912 	pgm->code = PGM_PROTECTION;
913 
914 	return pgm->code;
915 }
916