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KVM: s390: add architecture compliant guest access functions
[deliverable/linux.git] / arch / s390 / kvm / gaccess.c
CommitLineData
22938978
HC		 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
14union asce {
15 unsigned long val;
16 struct {
17 unsigned long origin : 52; /* Region- or Segment-Table Origin */
18 unsigned long : 2;
19 unsigned long g : 1; /* Subspace Group Control */
20 unsigned long p : 1; /* Private Space Control */
21 unsigned long s : 1; /* Storage-Alteration-Event Control */
22 unsigned long x : 1; /* Space-Switch-Event Control */
23 unsigned long r : 1; /* Real-Space Control */
24 unsigned long : 1;
25 unsigned long dt : 2; /* Designation-Type Control */
26 unsigned long tl : 2; /* Region- or Segment-Table Length */
27 };
28};
29
30enum {
31 ASCE_TYPE_SEGMENT = 0,
32 ASCE_TYPE_REGION3 = 1,
33 ASCE_TYPE_REGION2 = 2,
34 ASCE_TYPE_REGION1 = 3
35};
36
37union region1_table_entry {
38 unsigned long val;
39 struct {
40 unsigned long rto: 52;/* Region-Table Origin */
41 unsigned long : 2;
42 unsigned long p : 1; /* DAT-Protection Bit */
43 unsigned long : 1;
44 unsigned long tf : 2; /* Region-Second-Table Offset */
45 unsigned long i : 1; /* Region-Invalid Bit */
46 unsigned long : 1;
47 unsigned long tt : 2; /* Table-Type Bits */
48 unsigned long tl : 2; /* Region-Second-Table Length */
49 };
50};
51
52union region2_table_entry {
53 unsigned long val;
54 struct {
55 unsigned long rto: 52;/* Region-Table Origin */
56 unsigned long : 2;
57 unsigned long p : 1; /* DAT-Protection Bit */
58 unsigned long : 1;
59 unsigned long tf : 2; /* Region-Third-Table Offset */
60 unsigned long i : 1; /* Region-Invalid Bit */
61 unsigned long : 1;
62 unsigned long tt : 2; /* Table-Type Bits */
63 unsigned long tl : 2; /* Region-Third-Table Length */
64 };
65};
66
67struct region3_table_entry_fc0 {
68 unsigned long sto: 52;/* Segment-Table Origin */
69 unsigned long : 1;
70 unsigned long fc : 1; /* Format-Control */
71 unsigned long p : 1; /* DAT-Protection Bit */
72 unsigned long : 1;
73 unsigned long tf : 2; /* Segment-Table Offset */
74 unsigned long i : 1; /* Region-Invalid Bit */
75 unsigned long cr : 1; /* Common-Region Bit */
76 unsigned long tt : 2; /* Table-Type Bits */
77 unsigned long tl : 2; /* Segment-Table Length */
78};
79
80struct region3_table_entry_fc1 {
81 unsigned long rfaa : 33; /* Region-Frame Absolute Address */
82 unsigned long : 14;
83 unsigned long av : 1; /* ACCF-Validity Control */
84 unsigned long acc: 4; /* Access-Control Bits */
85 unsigned long f : 1; /* Fetch-Protection Bit */
86 unsigned long fc : 1; /* Format-Control */
87 unsigned long p : 1; /* DAT-Protection Bit */
88 unsigned long co : 1; /* Change-Recording Override */
89 unsigned long : 2;
90 unsigned long i : 1; /* Region-Invalid Bit */
91 unsigned long cr : 1; /* Common-Region Bit */
92 unsigned long tt : 2; /* Table-Type Bits */
93 unsigned long : 2;
94};
95
96union region3_table_entry {
97 unsigned long val;
98 struct region3_table_entry_fc0 fc0;
99 struct region3_table_entry_fc1 fc1;
100 struct {
101 unsigned long : 53;
102 unsigned long fc : 1; /* Format-Control */
103 unsigned long : 4;
104 unsigned long i : 1; /* Region-Invalid Bit */
105 unsigned long cr : 1; /* Common-Region Bit */
106 unsigned long tt : 2; /* Table-Type Bits */
107 unsigned long : 2;
108 };
109};
110
111struct segment_entry_fc0 {
112 unsigned long pto: 53;/* Page-Table Origin */
113 unsigned long fc : 1; /* Format-Control */
114 unsigned long p : 1; /* DAT-Protection Bit */
115 unsigned long : 3;
116 unsigned long i : 1; /* Segment-Invalid Bit */
117 unsigned long cs : 1; /* Common-Segment Bit */
118 unsigned long tt : 2; /* Table-Type Bits */
119 unsigned long : 2;
120};
121
122struct segment_entry_fc1 {
123 unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
124 unsigned long : 3;
125 unsigned long av : 1; /* ACCF-Validity Control */
126 unsigned long acc: 4; /* Access-Control Bits */
127 unsigned long f : 1; /* Fetch-Protection Bit */
128 unsigned long fc : 1; /* Format-Control */
129 unsigned long p : 1; /* DAT-Protection Bit */
130 unsigned long co : 1; /* Change-Recording Override */
131 unsigned long : 2;
132 unsigned long i : 1; /* Segment-Invalid Bit */
133 unsigned long cs : 1; /* Common-Segment Bit */
134 unsigned long tt : 2; /* Table-Type Bits */
135 unsigned long : 2;
136};
137
138union segment_table_entry {
139 unsigned long val;
140 struct segment_entry_fc0 fc0;
141 struct segment_entry_fc1 fc1;
142 struct {
143 unsigned long : 53;
144 unsigned long fc : 1; /* Format-Control */
145 unsigned long : 4;
146 unsigned long i : 1; /* Segment-Invalid Bit */
147 unsigned long cs : 1; /* Common-Segment Bit */
148 unsigned long tt : 2; /* Table-Type Bits */
149 unsigned long : 2;
150 };
151};
152
153enum {
154 TABLE_TYPE_SEGMENT = 0,
155 TABLE_TYPE_REGION3 = 1,
156 TABLE_TYPE_REGION2 = 2,
157 TABLE_TYPE_REGION1 = 3
158};
159
160union page_table_entry {
161 unsigned long val;
162 struct {
163 unsigned long pfra : 52; /* Page-Frame Real Address */
164 unsigned long z : 1; /* Zero Bit */
165 unsigned long i : 1; /* Page-Invalid Bit */
166 unsigned long p : 1; /* DAT-Protection Bit */
167 unsigned long co : 1; /* Change-Recording Override */
168 unsigned long : 8;
169 };
170};
171
172/*
173 * vaddress union in order to easily decode a virtual address into its
174 * region first index, region second index etc. parts.
175 */
176union vaddress {
177 unsigned long addr;
178 struct {
179 unsigned long rfx : 11;
180 unsigned long rsx : 11;
181 unsigned long rtx : 11;
182 unsigned long sx : 11;
183 unsigned long px : 8;
184 unsigned long bx : 12;
185 };
186 struct {
187 unsigned long rfx01 : 2;
188 unsigned long : 9;
189 unsigned long rsx01 : 2;
190 unsigned long : 9;
191 unsigned long rtx01 : 2;
192 unsigned long : 9;
193 unsigned long sx01 : 2;
194 unsigned long : 29;
195 };
196};
197
198/*
199 * raddress union which will contain the result (real or absolute address)
200 * after a page table walk. The rfaa, sfaa and pfra members are used to
201 * simply assign them the value of a region, segment or page table entry.
202 */
203union raddress {
204 unsigned long addr;
205 unsigned long rfaa : 33; /* Region-Frame Absolute Address */
206 unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
207 unsigned long pfra : 52; /* Page-Frame Real Address */
208};
209
210static unsigned long get_vcpu_asce(struct kvm_vcpu *vcpu)
211{
212 switch (psw_bits(vcpu->arch.sie_block->gpsw).as) {
213 case PSW_AS_PRIMARY:
214 return vcpu->arch.sie_block->gcr[1];
215 case PSW_AS_SECONDARY:
216 return vcpu->arch.sie_block->gcr[7];
217 case PSW_AS_HOME:
218 return vcpu->arch.sie_block->gcr[13];
219 }
220 return 0;
221}
222
223static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val)
224{
225 return kvm_read_guest(kvm, gpa, val, sizeof(*val));
226}
227
228/**
229 * guest_translate - translate a guest virtual into a guest absolute address
230 * @vcpu: virtual cpu
231 * @gva: guest virtual address
232 * @gpa: points to where guest physical (absolute) address should be stored
233 * @write: indicates if access is a write access
234 *
235 * Translate a guest virtual address into a guest absolute address by means
236 * of dynamic address translation as specified by the architecuture.
237 * If the resulting absolute address is not available in the configuration
238 * an addressing exception is indicated and @gpa will not be changed.
239 *
240 * Returns: - zero on success; @gpa contains the resulting absolute address
241 * - a negative value if guest access failed due to e.g. broken
242 * guest mapping
243 * - a positve value if an access exception happened. In this case
244 * the returned value is the program interruption code as defined
245 * by the architecture
246 */
247static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
248 unsigned long *gpa, int write)
249{
250 union vaddress vaddr = {.addr = gva};
251 union raddress raddr = {.addr = gva};
252 union page_table_entry pte;
253 int dat_protection = 0;
254 union ctlreg0 ctlreg0;
255 unsigned long ptr;
256 int edat1, edat2;
257 union asce asce;
258
259 ctlreg0.val = vcpu->arch.sie_block->gcr[0];
260 edat1 = ctlreg0.edat && test_vfacility(8);
261 edat2 = edat1 && test_vfacility(78);
262 asce.val = get_vcpu_asce(vcpu);
263 if (asce.r)
264 goto real_address;
265 ptr = asce.origin * 4096;
266 switch (asce.dt) {
267 case ASCE_TYPE_REGION1:
268 if (vaddr.rfx01 > asce.tl)
269 return PGM_REGION_FIRST_TRANS;
270 ptr += vaddr.rfx * 8;
271 break;
272 case ASCE_TYPE_REGION2:
273 if (vaddr.rfx)
274 return PGM_ASCE_TYPE;
275 if (vaddr.rsx01 > asce.tl)
276 return PGM_REGION_SECOND_TRANS;
277 ptr += vaddr.rsx * 8;
278 break;
279 case ASCE_TYPE_REGION3:
280 if (vaddr.rfx || vaddr.rsx)
281 return PGM_ASCE_TYPE;
282 if (vaddr.rtx01 > asce.tl)
283 return PGM_REGION_THIRD_TRANS;
284 ptr += vaddr.rtx * 8;
285 break;
286 case ASCE_TYPE_SEGMENT:
287 if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
288 return PGM_ASCE_TYPE;
289 if (vaddr.sx01 > asce.tl)
290 return PGM_SEGMENT_TRANSLATION;
291 ptr += vaddr.sx * 8;
292 break;
293 }
294 switch (asce.dt) {
295 case ASCE_TYPE_REGION1: {
296 union region1_table_entry rfte;
297
298 if (kvm_is_error_gpa(vcpu->kvm, ptr))
299 return PGM_ADDRESSING;
300 if (deref_table(vcpu->kvm, ptr, &rfte.val))
301 return -EFAULT;
302 if (rfte.i)
303 return PGM_REGION_FIRST_TRANS;
304 if (rfte.tt != TABLE_TYPE_REGION1)
305 return PGM_TRANSLATION_SPEC;
306 if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
307 return PGM_REGION_SECOND_TRANS;
308 if (edat1)
309 dat_protection |= rfte.p;
310 ptr = rfte.rto * 4096 + vaddr.rsx * 8;
311 }
312 /* fallthrough */
313 case ASCE_TYPE_REGION2: {
314 union region2_table_entry rste;
315
316 if (kvm_is_error_gpa(vcpu->kvm, ptr))
317 return PGM_ADDRESSING;
318 if (deref_table(vcpu->kvm, ptr, &rste.val))
319 return -EFAULT;
320 if (rste.i)
321 return PGM_REGION_SECOND_TRANS;
322 if (rste.tt != TABLE_TYPE_REGION2)
323 return PGM_TRANSLATION_SPEC;
324 if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
325 return PGM_REGION_THIRD_TRANS;
326 if (edat1)
327 dat_protection |= rste.p;
328 ptr = rste.rto * 4096 + vaddr.rtx * 8;
329 }
330 /* fallthrough */
331 case ASCE_TYPE_REGION3: {
332 union region3_table_entry rtte;
333
334 if (kvm_is_error_gpa(vcpu->kvm, ptr))
335 return PGM_ADDRESSING;
336 if (deref_table(vcpu->kvm, ptr, &rtte.val))
337 return -EFAULT;
338 if (rtte.i)
339 return PGM_REGION_THIRD_TRANS;
340 if (rtte.tt != TABLE_TYPE_REGION3)
341 return PGM_TRANSLATION_SPEC;
342 if (rtte.cr && asce.p && edat2)
343 return PGM_TRANSLATION_SPEC;
344 if (rtte.fc && edat2) {
345 dat_protection |= rtte.fc1.p;
346 raddr.rfaa = rtte.fc1.rfaa;
347 goto absolute_address;
348 }
349 if (vaddr.sx01 < rtte.fc0.tf)
350 return PGM_SEGMENT_TRANSLATION;
351 if (vaddr.sx01 > rtte.fc0.tl)
352 return PGM_SEGMENT_TRANSLATION;
353 if (edat1)
354 dat_protection |= rtte.fc0.p;
355 ptr = rtte.fc0.sto * 4096 + vaddr.sx * 8;
356 }
357 /* fallthrough */
358 case ASCE_TYPE_SEGMENT: {
359 union segment_table_entry ste;
360
361 if (kvm_is_error_gpa(vcpu->kvm, ptr))
362 return PGM_ADDRESSING;
363 if (deref_table(vcpu->kvm, ptr, &ste.val))
364 return -EFAULT;
365 if (ste.i)
366 return PGM_SEGMENT_TRANSLATION;
367 if (ste.tt != TABLE_TYPE_SEGMENT)
368 return PGM_TRANSLATION_SPEC;
369 if (ste.cs && asce.p)
370 return PGM_TRANSLATION_SPEC;
371 if (ste.fc && edat1) {
372 dat_protection |= ste.fc1.p;
373 raddr.sfaa = ste.fc1.sfaa;
374 goto absolute_address;
375 }
376 dat_protection |= ste.fc0.p;
377 ptr = ste.fc0.pto * 2048 + vaddr.px * 8;
378 }
379 }
380 if (kvm_is_error_gpa(vcpu->kvm, ptr))
381 return PGM_ADDRESSING;
382 if (deref_table(vcpu->kvm, ptr, &pte.val))
383 return -EFAULT;
384 if (pte.i)
385 return PGM_PAGE_TRANSLATION;
386 if (pte.z)
387 return PGM_TRANSLATION_SPEC;
388 if (pte.co && !edat1)
389 return PGM_TRANSLATION_SPEC;
390 dat_protection |= pte.p;
391 raddr.pfra = pte.pfra;
392real_address:
393 raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr);
394absolute_address:
395 if (write && dat_protection)
396 return PGM_PROTECTION;
397 if (kvm_is_error_gpa(vcpu->kvm, raddr.addr))
398 return PGM_ADDRESSING;
399 *gpa = raddr.addr;
400 return 0;
401}
402
403static inline int is_low_address(unsigned long ga)
404{
405 /* Check for address ranges 0..511 and 4096..4607 */
406 return (ga & ~0x11fful) == 0;
407}
408
409static int low_address_protection_enabled(struct kvm_vcpu *vcpu)
410{
411 union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
412 psw_t *psw = &vcpu->arch.sie_block->gpsw;
413 union asce asce;
414
415 if (!ctlreg0.lap)
416 return 0;
417 asce.val = get_vcpu_asce(vcpu);
418 if (psw_bits(*psw).t && asce.p)
419 return 0;
420 return 1;
421}
422
423struct trans_exc_code_bits {
424 unsigned long addr : 52; /* Translation-exception Address */
425 unsigned long fsi : 2; /* Access Exception Fetch/Store Indication */
426 unsigned long : 7;
427 unsigned long b61 : 1;
428 unsigned long as : 2; /* ASCE Identifier */
429};
430
431enum {
432 FSI_UNKNOWN = 0, /* Unknown wether fetch or store */
433 FSI_STORE = 1, /* Exception was due to store operation */
434 FSI_FETCH = 2 /* Exception was due to fetch operation */
435};
436
437static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga,
438 unsigned long *pages, unsigned long nr_pages,
439 int write)
440{
441 struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
442 psw_t *psw = &vcpu->arch.sie_block->gpsw;
443 struct trans_exc_code_bits *tec_bits;
444 int lap_enabled, rc;
445
446 memset(pgm, 0, sizeof(*pgm));
447 tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
448 tec_bits->fsi = write ? FSI_STORE : FSI_FETCH;
449 tec_bits->as = psw_bits(*psw).as;
450 lap_enabled = low_address_protection_enabled(vcpu);
451 while (nr_pages) {
452 ga = kvm_s390_logical_to_effective(vcpu, ga);
453 tec_bits->addr = ga >> PAGE_SHIFT;
454 if (write && lap_enabled && is_low_address(ga)) {
455 pgm->code = PGM_PROTECTION;
456 return pgm->code;
457 }
458 ga &= PAGE_MASK;
459 if (psw_bits(*psw).t) {
460 rc = guest_translate(vcpu, ga, pages, write);
461 if (rc < 0)
462 return rc;
463 if (rc == PGM_PROTECTION)
464 tec_bits->b61 = 1;
465 if (rc)
466 pgm->code = rc;
467 } else {
468 *pages = kvm_s390_real_to_abs(vcpu, ga);
469 if (kvm_is_error_gpa(vcpu->kvm, *pages))
470 pgm->code = PGM_ADDRESSING;
471 }
472 if (pgm->code)
473 return pgm->code;
474 ga += PAGE_SIZE;
475 pages++;
476 nr_pages--;
477 }
478 return 0;
479}
480
481int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
482 unsigned long len, int write)
483{
484 psw_t *psw = &vcpu->arch.sie_block->gpsw;
485 unsigned long _len, nr_pages, gpa, idx;
486 unsigned long pages_array[2];
487 unsigned long *pages;
488 int rc;
489
490 if (!len)
491 return 0;
492 /* Access register mode is not supported yet. */
493 if (psw_bits(*psw).t && psw_bits(*psw).as == PSW_AS_ACCREG)
494 return -EOPNOTSUPP;
495 nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1;
496 pages = pages_array;
497 if (nr_pages > ARRAY_SIZE(pages_array))
498 pages = vmalloc(nr_pages * sizeof(unsigned long));
499 if (!pages)
500 return -ENOMEM;
501 rc = guest_page_range(vcpu, ga, pages, nr_pages, write);
502 for (idx = 0; idx < nr_pages && !rc; idx++) {
503 gpa = *(pages + idx) + (ga & ~PAGE_MASK);
504 _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
505 if (write)
506 rc = kvm_write_guest(vcpu->kvm, gpa, data, _len);
507 else
508 rc = kvm_read_guest(vcpu->kvm, gpa, data, _len);
509 len -= _len;
510 ga += _len;
511 data += _len;
512 }
513 if (nr_pages > ARRAY_SIZE(pages_array))
514 vfree(pages);
515 return rc;
516}
517
518int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
519 void *data, unsigned long len, int write)
520{
521 unsigned long _len, gpa;
522 int rc = 0;
523
524 while (len && !rc) {
525 gpa = kvm_s390_real_to_abs(vcpu, gra);
526 _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
527 if (write)
528 rc = write_guest_abs(vcpu, gpa, data, _len);
529 else
530 rc = read_guest_abs(vcpu, gpa, data, _len);
531 len -= _len;
532 gra += _len;
533 data += _len;
534 }
535 return rc;
536}
Linux kernel - Deliverables
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