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TOMOYO Linux Cross Reference
Linux/arch/s390/kvm/vsie.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * kvm nested virtualization support for s390x
  4  *
  5  * Copyright IBM Corp. 2016, 2018
  6  *
  7  *    Author(s): David Hildenbrand <dahi@linux.vnet.ibm.com>
  8  */
  9 #include <linux/vmalloc.h>
 10 #include <linux/kvm_host.h>
 11 #include <linux/bug.h>
 12 #include <linux/list.h>
 13 #include <linux/bitmap.h>
 14 #include <linux/sched/signal.h>
 15 
 16 #include <asm/gmap.h>
 17 #include <asm/mmu_context.h>
 18 #include <asm/sclp.h>
 19 #include <asm/nmi.h>
 20 #include <asm/dis.h>
 21 #include "kvm-s390.h"
 22 #include "gaccess.h"
 23 
 24 struct vsie_page {
 25         struct kvm_s390_sie_block scb_s;        /* 0x0000 */
 26         /*
 27          * the backup info for machine check. ensure it's at
 28          * the same offset as that in struct sie_page!
 29          */
 30         struct mcck_volatile_info mcck_info;    /* 0x0200 */
 31         /*
 32          * The pinned original scb. Be aware that other VCPUs can modify
 33          * it while we read from it. Values that are used for conditions or
 34          * are reused conditionally, should be accessed via READ_ONCE.
 35          */
 36         struct kvm_s390_sie_block *scb_o;       /* 0x0218 */
 37         /* the shadow gmap in use by the vsie_page */
 38         struct gmap *gmap;                      /* 0x0220 */
 39         /* address of the last reported fault to guest2 */
 40         unsigned long fault_addr;               /* 0x0228 */
 41         /* calculated guest addresses of satellite control blocks */
 42         gpa_t sca_gpa;                          /* 0x0230 */
 43         gpa_t itdba_gpa;                        /* 0x0238 */
 44         gpa_t gvrd_gpa;                         /* 0x0240 */
 45         gpa_t riccbd_gpa;                       /* 0x0248 */
 46         gpa_t sdnx_gpa;                         /* 0x0250 */
 47         __u8 reserved[0x0700 - 0x0258];         /* 0x0258 */
 48         struct kvm_s390_crypto_cb crycb;        /* 0x0700 */
 49         __u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE]; /* 0x0800 */
 50 };
 51 
 52 /* trigger a validity icpt for the given scb */
 53 static int set_validity_icpt(struct kvm_s390_sie_block *scb,
 54                              __u16 reason_code)
 55 {
 56         scb->ipa = 0x1000;
 57         scb->ipb = ((__u32) reason_code) << 16;
 58         scb->icptcode = ICPT_VALIDITY;
 59         return 1;
 60 }
 61 
 62 /* mark the prefix as unmapped, this will block the VSIE */
 63 static void prefix_unmapped(struct vsie_page *vsie_page)
 64 {
 65         atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20);
 66 }
 67 
 68 /* mark the prefix as unmapped and wait until the VSIE has been left */
 69 static void prefix_unmapped_sync(struct vsie_page *vsie_page)
 70 {
 71         prefix_unmapped(vsie_page);
 72         if (vsie_page->scb_s.prog0c & PROG_IN_SIE)
 73                 atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags);
 74         while (vsie_page->scb_s.prog0c & PROG_IN_SIE)
 75                 cpu_relax();
 76 }
 77 
 78 /* mark the prefix as mapped, this will allow the VSIE to run */
 79 static void prefix_mapped(struct vsie_page *vsie_page)
 80 {
 81         atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20);
 82 }
 83 
 84 /* test if the prefix is mapped into the gmap shadow */
 85 static int prefix_is_mapped(struct vsie_page *vsie_page)
 86 {
 87         return !(atomic_read(&vsie_page->scb_s.prog20) & PROG_REQUEST);
 88 }
 89 
 90 /* copy the updated intervention request bits into the shadow scb */
 91 static void update_intervention_requests(struct vsie_page *vsie_page)
 92 {
 93         const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT;
 94         int cpuflags;
 95 
 96         cpuflags = atomic_read(&vsie_page->scb_o->cpuflags);
 97         atomic_andnot(bits, &vsie_page->scb_s.cpuflags);
 98         atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags);
 99 }
100 
101 /* shadow (filter and validate) the cpuflags  */
102 static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
103 {
104         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
105         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
106         int newflags, cpuflags = atomic_read(&scb_o->cpuflags);
107 
108         /* we don't allow ESA/390 guests */
109         if (!(cpuflags & CPUSTAT_ZARCH))
110                 return set_validity_icpt(scb_s, 0x0001U);
111 
112         if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS))
113                 return set_validity_icpt(scb_s, 0x0001U);
114         else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR))
115                 return set_validity_icpt(scb_s, 0x0007U);
116 
117         /* intervention requests will be set later */
118         newflags = CPUSTAT_ZARCH;
119         if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8))
120                 newflags |= CPUSTAT_GED;
121         if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) {
122                 if (cpuflags & CPUSTAT_GED)
123                         return set_validity_icpt(scb_s, 0x0001U);
124                 newflags |= CPUSTAT_GED2;
125         }
126         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GPERE))
127                 newflags |= cpuflags & CPUSTAT_P;
128         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GSLS))
129                 newflags |= cpuflags & CPUSTAT_SM;
130         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IBS))
131                 newflags |= cpuflags & CPUSTAT_IBS;
132         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_KSS))
133                 newflags |= cpuflags & CPUSTAT_KSS;
134 
135         atomic_set(&scb_s->cpuflags, newflags);
136         return 0;
137 }
138 /* Copy to APCB FORMAT1 from APCB FORMAT0 */
139 static int setup_apcb10(struct kvm_vcpu *vcpu, struct kvm_s390_apcb1 *apcb_s,
140                         unsigned long apcb_o, struct kvm_s390_apcb1 *apcb_h)
141 {
142         struct kvm_s390_apcb0 tmp;
143 
144         if (read_guest_real(vcpu, apcb_o, &tmp, sizeof(struct kvm_s390_apcb0)))
145                 return -EFAULT;
146 
147         apcb_s->apm[0] = apcb_h->apm[0] & tmp.apm[0];
148         apcb_s->aqm[0] = apcb_h->aqm[0] & tmp.aqm[0] & 0xffff000000000000UL;
149         apcb_s->adm[0] = apcb_h->adm[0] & tmp.adm[0] & 0xffff000000000000UL;
150 
151         return 0;
152 
153 }
154 
155 /**
156  * setup_apcb00 - Copy to APCB FORMAT0 from APCB FORMAT0
157  * @vcpu: pointer to the virtual CPU
158  * @apcb_s: pointer to start of apcb in the shadow crycb
159  * @apcb_o: pointer to start of original apcb in the guest2
160  * @apcb_h: pointer to start of apcb in the guest1
161  *
162  * Returns 0 and -EFAULT on error reading guest apcb
163  */
164 static int setup_apcb00(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
165                         unsigned long apcb_o, unsigned long *apcb_h)
166 {
167         if (read_guest_real(vcpu, apcb_o, apcb_s,
168                             sizeof(struct kvm_s390_apcb0)))
169                 return -EFAULT;
170 
171         bitmap_and(apcb_s, apcb_s, apcb_h, sizeof(struct kvm_s390_apcb0));
172 
173         return 0;
174 }
175 
176 /**
177  * setup_apcb11 - Copy the FORMAT1 APCB from the guest to the shadow CRYCB
178  * @vcpu: pointer to the virtual CPU
179  * @apcb_s: pointer to start of apcb in the shadow crycb
180  * @apcb_o: pointer to start of original guest apcb
181  * @apcb_h: pointer to start of apcb in the host
182  *
183  * Returns 0 and -EFAULT on error reading guest apcb
184  */
185 static int setup_apcb11(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
186                         unsigned long apcb_o,
187                         unsigned long *apcb_h)
188 {
189         if (read_guest_real(vcpu, apcb_o, apcb_s,
190                             sizeof(struct kvm_s390_apcb1)))
191                 return -EFAULT;
192 
193         bitmap_and(apcb_s, apcb_s, apcb_h, sizeof(struct kvm_s390_apcb1));
194 
195         return 0;
196 }
197 
198 /**
199  * setup_apcb - Create a shadow copy of the apcb.
200  * @vcpu: pointer to the virtual CPU
201  * @crycb_s: pointer to shadow crycb
202  * @crycb_o: pointer to original guest crycb
203  * @crycb_h: pointer to the host crycb
204  * @fmt_o: format of the original guest crycb.
205  * @fmt_h: format of the host crycb.
206  *
207  * Checks the compatibility between the guest and host crycb and calls the
208  * appropriate copy function.
209  *
210  * Return 0 or an error number if the guest and host crycb are incompatible.
211  */
212 static int setup_apcb(struct kvm_vcpu *vcpu, struct kvm_s390_crypto_cb *crycb_s,
213                const u32 crycb_o,
214                struct kvm_s390_crypto_cb *crycb_h,
215                int fmt_o, int fmt_h)
216 {
217         struct kvm_s390_crypto_cb *crycb;
218 
219         crycb = (struct kvm_s390_crypto_cb *) (unsigned long)crycb_o;
220 
221         switch (fmt_o) {
222         case CRYCB_FORMAT2:
223                 if ((crycb_o & PAGE_MASK) != ((crycb_o + 256) & PAGE_MASK))
224                         return -EACCES;
225                 if (fmt_h != CRYCB_FORMAT2)
226                         return -EINVAL;
227                 return setup_apcb11(vcpu, (unsigned long *)&crycb_s->apcb1,
228                                     (unsigned long) &crycb->apcb1,
229                                     (unsigned long *)&crycb_h->apcb1);
230         case CRYCB_FORMAT1:
231                 switch (fmt_h) {
232                 case CRYCB_FORMAT2:
233                         return setup_apcb10(vcpu, &crycb_s->apcb1,
234                                             (unsigned long) &crycb->apcb0,
235                                             &crycb_h->apcb1);
236                 case CRYCB_FORMAT1:
237                         return setup_apcb00(vcpu,
238                                             (unsigned long *) &crycb_s->apcb0,
239                                             (unsigned long) &crycb->apcb0,
240                                             (unsigned long *) &crycb_h->apcb0);
241                 }
242                 break;
243         case CRYCB_FORMAT0:
244                 if ((crycb_o & PAGE_MASK) != ((crycb_o + 32) & PAGE_MASK))
245                         return -EACCES;
246 
247                 switch (fmt_h) {
248                 case CRYCB_FORMAT2:
249                         return setup_apcb10(vcpu, &crycb_s->apcb1,
250                                             (unsigned long) &crycb->apcb0,
251                                             &crycb_h->apcb1);
252                 case CRYCB_FORMAT1:
253                 case CRYCB_FORMAT0:
254                         return setup_apcb00(vcpu,
255                                             (unsigned long *) &crycb_s->apcb0,
256                                             (unsigned long) &crycb->apcb0,
257                                             (unsigned long *) &crycb_h->apcb0);
258                 }
259         }
260         return -EINVAL;
261 }
262 
263 /**
264  * shadow_crycb - Create a shadow copy of the crycb block
265  * @vcpu: a pointer to the virtual CPU
266  * @vsie_page: a pointer to internal date used for the vSIE
267  *
268  * Create a shadow copy of the crycb block and setup key wrapping, if
269  * requested for guest 3 and enabled for guest 2.
270  *
271  * We accept format-1 or format-2, but we convert format-1 into format-2
272  * in the shadow CRYCB.
273  * Using format-2 enables the firmware to choose the right format when
274  * scheduling the SIE.
275  * There is nothing to do for format-0.
276  *
277  * This function centralize the issuing of set_validity_icpt() for all
278  * the subfunctions working on the crycb.
279  *
280  * Returns: - 0 if shadowed or nothing to do
281  *          - > 0 if control has to be given to guest 2
282  */
283 static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
284 {
285         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
286         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
287         const uint32_t crycbd_o = READ_ONCE(scb_o->crycbd);
288         const u32 crycb_addr = crycbd_o & 0x7ffffff8U;
289         unsigned long *b1, *b2;
290         u8 ecb3_flags;
291         int apie_h;
292         int key_msk = test_kvm_facility(vcpu->kvm, 76);
293         int fmt_o = crycbd_o & CRYCB_FORMAT_MASK;
294         int fmt_h = vcpu->arch.sie_block->crycbd & CRYCB_FORMAT_MASK;
295         int ret = 0;
296 
297         scb_s->crycbd = 0;
298 
299         apie_h = vcpu->arch.sie_block->eca & ECA_APIE;
300         if (!apie_h && !key_msk)
301                 return 0;
302 
303         if (!crycb_addr)
304                 return set_validity_icpt(scb_s, 0x0039U);
305 
306         if (fmt_o == CRYCB_FORMAT1)
307                 if ((crycb_addr & PAGE_MASK) !=
308                     ((crycb_addr + 128) & PAGE_MASK))
309                         return set_validity_icpt(scb_s, 0x003CU);
310 
311         if (apie_h && (scb_o->eca & ECA_APIE)) {
312                 ret = setup_apcb(vcpu, &vsie_page->crycb, crycb_addr,
313                                  vcpu->kvm->arch.crypto.crycb,
314                                  fmt_o, fmt_h);
315                 if (ret)
316                         goto end;
317                 scb_s->eca |= scb_o->eca & ECA_APIE;
318         }
319 
320         /* we may only allow it if enabled for guest 2 */
321         ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
322                      (ECB3_AES | ECB3_DEA);
323         if (!ecb3_flags)
324                 goto end;
325 
326         /* copy only the wrapping keys */
327         if (read_guest_real(vcpu, crycb_addr + 72,
328                             vsie_page->crycb.dea_wrapping_key_mask, 56))
329                 return set_validity_icpt(scb_s, 0x0035U);
330 
331         scb_s->ecb3 |= ecb3_flags;
332 
333         /* xor both blocks in one run */
334         b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask;
335         b2 = (unsigned long *)
336                             vcpu->kvm->arch.crypto.crycb->dea_wrapping_key_mask;
337         /* as 56%8 == 0, bitmap_xor won't overwrite any data */
338         bitmap_xor(b1, b1, b2, BITS_PER_BYTE * 56);
339 end:
340         switch (ret) {
341         case -EINVAL:
342                 return set_validity_icpt(scb_s, 0x0020U);
343         case -EFAULT:
344                 return set_validity_icpt(scb_s, 0x0035U);
345         case -EACCES:
346                 return set_validity_icpt(scb_s, 0x003CU);
347         }
348         scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT2;
349         return 0;
350 }
351 
352 /* shadow (round up/down) the ibc to avoid validity icpt */
353 static void prepare_ibc(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
354 {
355         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
356         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
357         /* READ_ONCE does not work on bitfields - use a temporary variable */
358         const uint32_t __new_ibc = scb_o->ibc;
359         const uint32_t new_ibc = READ_ONCE(__new_ibc) & 0x0fffU;
360         __u64 min_ibc = (sclp.ibc >> 16) & 0x0fffU;
361 
362         scb_s->ibc = 0;
363         /* ibc installed in g2 and requested for g3 */
364         if (vcpu->kvm->arch.model.ibc && new_ibc) {
365                 scb_s->ibc = new_ibc;
366                 /* takte care of the minimum ibc level of the machine */
367                 if (scb_s->ibc < min_ibc)
368                         scb_s->ibc = min_ibc;
369                 /* take care of the maximum ibc level set for the guest */
370                 if (scb_s->ibc > vcpu->kvm->arch.model.ibc)
371                         scb_s->ibc = vcpu->kvm->arch.model.ibc;
372         }
373 }
374 
375 /* unshadow the scb, copying parameters back to the real scb */
376 static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
377 {
378         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
379         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
380 
381         /* interception */
382         scb_o->icptcode = scb_s->icptcode;
383         scb_o->icptstatus = scb_s->icptstatus;
384         scb_o->ipa = scb_s->ipa;
385         scb_o->ipb = scb_s->ipb;
386         scb_o->gbea = scb_s->gbea;
387 
388         /* timer */
389         scb_o->cputm = scb_s->cputm;
390         scb_o->ckc = scb_s->ckc;
391         scb_o->todpr = scb_s->todpr;
392 
393         /* guest state */
394         scb_o->gpsw = scb_s->gpsw;
395         scb_o->gg14 = scb_s->gg14;
396         scb_o->gg15 = scb_s->gg15;
397         memcpy(scb_o->gcr, scb_s->gcr, 128);
398         scb_o->pp = scb_s->pp;
399 
400         /* branch prediction */
401         if (test_kvm_facility(vcpu->kvm, 82)) {
402                 scb_o->fpf &= ~FPF_BPBC;
403                 scb_o->fpf |= scb_s->fpf & FPF_BPBC;
404         }
405 
406         /* interrupt intercept */
407         switch (scb_s->icptcode) {
408         case ICPT_PROGI:
409         case ICPT_INSTPROGI:
410         case ICPT_EXTINT:
411                 memcpy((void *)((u64)scb_o + 0xc0),
412                        (void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0);
413                 break;
414         case ICPT_PARTEXEC:
415                 /* MVPG only */
416                 memcpy((void *)((u64)scb_o + 0xc0),
417                        (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0);
418                 break;
419         }
420 
421         if (scb_s->ihcpu != 0xffffU)
422                 scb_o->ihcpu = scb_s->ihcpu;
423 }
424 
425 /*
426  * Setup the shadow scb by copying and checking the relevant parts of the g2
427  * provided scb.
428  *
429  * Returns: - 0 if the scb has been shadowed
430  *          - > 0 if control has to be given to guest 2
431  */
432 static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
433 {
434         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
435         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
436         /* READ_ONCE does not work on bitfields - use a temporary variable */
437         const uint32_t __new_prefix = scb_o->prefix;
438         const uint32_t new_prefix = READ_ONCE(__new_prefix);
439         const bool wants_tx = READ_ONCE(scb_o->ecb) & ECB_TE;
440         bool had_tx = scb_s->ecb & ECB_TE;
441         unsigned long new_mso = 0;
442         int rc;
443 
444         /* make sure we don't have any leftovers when reusing the scb */
445         scb_s->icptcode = 0;
446         scb_s->eca = 0;
447         scb_s->ecb = 0;
448         scb_s->ecb2 = 0;
449         scb_s->ecb3 = 0;
450         scb_s->ecd = 0;
451         scb_s->fac = 0;
452         scb_s->fpf = 0;
453 
454         rc = prepare_cpuflags(vcpu, vsie_page);
455         if (rc)
456                 goto out;
457 
458         /* timer */
459         scb_s->cputm = scb_o->cputm;
460         scb_s->ckc = scb_o->ckc;
461         scb_s->todpr = scb_o->todpr;
462         scb_s->epoch = scb_o->epoch;
463 
464         /* guest state */
465         scb_s->gpsw = scb_o->gpsw;
466         scb_s->gg14 = scb_o->gg14;
467         scb_s->gg15 = scb_o->gg15;
468         memcpy(scb_s->gcr, scb_o->gcr, 128);
469         scb_s->pp = scb_o->pp;
470 
471         /* interception / execution handling */
472         scb_s->gbea = scb_o->gbea;
473         scb_s->lctl = scb_o->lctl;
474         scb_s->svcc = scb_o->svcc;
475         scb_s->ictl = scb_o->ictl;
476         /*
477          * SKEY handling functions can't deal with false setting of PTE invalid
478          * bits. Therefore we cannot provide interpretation and would later
479          * have to provide own emulation handlers.
480          */
481         if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_KSS))
482                 scb_s->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
483 
484         scb_s->icpua = scb_o->icpua;
485 
486         if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_SM))
487                 new_mso = READ_ONCE(scb_o->mso) & 0xfffffffffff00000UL;
488         /* if the hva of the prefix changes, we have to remap the prefix */
489         if (scb_s->mso != new_mso || scb_s->prefix != new_prefix)
490                 prefix_unmapped(vsie_page);
491          /* SIE will do mso/msl validity and exception checks for us */
492         scb_s->msl = scb_o->msl & 0xfffffffffff00000UL;
493         scb_s->mso = new_mso;
494         scb_s->prefix = new_prefix;
495 
496         /* We have to definetly flush the tlb if this scb never ran */
497         if (scb_s->ihcpu != 0xffffU)
498                 scb_s->ihcpu = scb_o->ihcpu;
499 
500         /* MVPG and Protection Exception Interpretation are always available */
501         scb_s->eca |= scb_o->eca & (ECA_MVPGI | ECA_PROTEXCI);
502         /* Host-protection-interruption introduced with ESOP */
503         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_ESOP))
504                 scb_s->ecb |= scb_o->ecb & ECB_HOSTPROTINT;
505         /* transactional execution */
506         if (test_kvm_facility(vcpu->kvm, 73) && wants_tx) {
507                 /* remap the prefix is tx is toggled on */
508                 if (!had_tx)
509                         prefix_unmapped(vsie_page);
510                 scb_s->ecb |= ECB_TE;
511         }
512         /* branch prediction */
513         if (test_kvm_facility(vcpu->kvm, 82))
514                 scb_s->fpf |= scb_o->fpf & FPF_BPBC;
515         /* SIMD */
516         if (test_kvm_facility(vcpu->kvm, 129)) {
517                 scb_s->eca |= scb_o->eca & ECA_VX;
518                 scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT;
519         }
520         /* Run-time-Instrumentation */
521         if (test_kvm_facility(vcpu->kvm, 64))
522                 scb_s->ecb3 |= scb_o->ecb3 & ECB3_RI;
523         /* Instruction Execution Prevention */
524         if (test_kvm_facility(vcpu->kvm, 130))
525                 scb_s->ecb2 |= scb_o->ecb2 & ECB2_IEP;
526         /* Guarded Storage */
527         if (test_kvm_facility(vcpu->kvm, 133)) {
528                 scb_s->ecb |= scb_o->ecb & ECB_GS;
529                 scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT;
530         }
531         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIIF))
532                 scb_s->eca |= scb_o->eca & ECA_SII;
533         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IB))
534                 scb_s->eca |= scb_o->eca & ECA_IB;
535         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI))
536                 scb_s->eca |= scb_o->eca & ECA_CEI;
537         /* Epoch Extension */
538         if (test_kvm_facility(vcpu->kvm, 139))
539                 scb_s->ecd |= scb_o->ecd & ECD_MEF;
540 
541         /* etoken */
542         if (test_kvm_facility(vcpu->kvm, 156))
543                 scb_s->ecd |= scb_o->ecd & ECD_ETOKENF;
544 
545         scb_s->hpid = HPID_VSIE;
546 
547         prepare_ibc(vcpu, vsie_page);
548         rc = shadow_crycb(vcpu, vsie_page);
549 out:
550         if (rc)
551                 unshadow_scb(vcpu, vsie_page);
552         return rc;
553 }
554 
555 void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
556                                  unsigned long end)
557 {
558         struct kvm *kvm = gmap->private;
559         struct vsie_page *cur;
560         unsigned long prefix;
561         struct page *page;
562         int i;
563 
564         if (!gmap_is_shadow(gmap))
565                 return;
566         if (start >= 1UL << 31)
567                 /* We are only interested in prefix pages */
568                 return;
569 
570         /*
571          * Only new shadow blocks are added to the list during runtime,
572          * therefore we can safely reference them all the time.
573          */
574         for (i = 0; i < kvm->arch.vsie.page_count; i++) {
575                 page = READ_ONCE(kvm->arch.vsie.pages[i]);
576                 if (!page)
577                         continue;
578                 cur = page_to_virt(page);
579                 if (READ_ONCE(cur->gmap) != gmap)
580                         continue;
581                 prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT;
582                 /* with mso/msl, the prefix lies at an offset */
583                 prefix += cur->scb_s.mso;
584                 if (prefix <= end && start <= prefix + 2 * PAGE_SIZE - 1)
585                         prefix_unmapped_sync(cur);
586         }
587 }
588 
589 /*
590  * Map the first prefix page and if tx is enabled also the second prefix page.
591  *
592  * The prefix will be protected, a gmap notifier will inform about unmaps.
593  * The shadow scb must not be executed until the prefix is remapped, this is
594  * guaranteed by properly handling PROG_REQUEST.
595  *
596  * Returns: - 0 on if successfully mapped or already mapped
597  *          - > 0 if control has to be given to guest 2
598  *          - -EAGAIN if the caller can retry immediately
599  *          - -ENOMEM if out of memory
600  */
601 static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
602 {
603         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
604         u64 prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
605         int rc;
606 
607         if (prefix_is_mapped(vsie_page))
608                 return 0;
609 
610         /* mark it as mapped so we can catch any concurrent unmappers */
611         prefix_mapped(vsie_page);
612 
613         /* with mso/msl, the prefix lies at offset *mso* */
614         prefix += scb_s->mso;
615 
616         rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix);
617         if (!rc && (scb_s->ecb & ECB_TE))
618                 rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
619                                            prefix + PAGE_SIZE);
620         /*
621          * We don't have to mprotect, we will be called for all unshadows.
622          * SIE will detect if protection applies and trigger a validity.
623          */
624         if (rc)
625                 prefix_unmapped(vsie_page);
626         if (rc > 0 || rc == -EFAULT)
627                 rc = set_validity_icpt(scb_s, 0x0037U);
628         return rc;
629 }
630 
631 /*
632  * Pin the guest page given by gpa and set hpa to the pinned host address.
633  * Will always be pinned writable.
634  *
635  * Returns: - 0 on success
636  *          - -EINVAL if the gpa is not valid guest storage
637  */
638 static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa)
639 {
640         struct page *page;
641 
642         page = gfn_to_page(kvm, gpa_to_gfn(gpa));
643         if (is_error_page(page))
644                 return -EINVAL;
645         *hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK);
646         return 0;
647 }
648 
649 /* Unpins a page previously pinned via pin_guest_page, marking it as dirty. */
650 static void unpin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t hpa)
651 {
652         kvm_release_pfn_dirty(hpa >> PAGE_SHIFT);
653         /* mark the page always as dirty for migration */
654         mark_page_dirty(kvm, gpa_to_gfn(gpa));
655 }
656 
657 /* unpin all blocks previously pinned by pin_blocks(), marking them dirty */
658 static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
659 {
660         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
661         hpa_t hpa;
662 
663         hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol;
664         if (hpa) {
665                 unpin_guest_page(vcpu->kvm, vsie_page->sca_gpa, hpa);
666                 vsie_page->sca_gpa = 0;
667                 scb_s->scaol = 0;
668                 scb_s->scaoh = 0;
669         }
670 
671         hpa = scb_s->itdba;
672         if (hpa) {
673                 unpin_guest_page(vcpu->kvm, vsie_page->itdba_gpa, hpa);
674                 vsie_page->itdba_gpa = 0;
675                 scb_s->itdba = 0;
676         }
677 
678         hpa = scb_s->gvrd;
679         if (hpa) {
680                 unpin_guest_page(vcpu->kvm, vsie_page->gvrd_gpa, hpa);
681                 vsie_page->gvrd_gpa = 0;
682                 scb_s->gvrd = 0;
683         }
684 
685         hpa = scb_s->riccbd;
686         if (hpa) {
687                 unpin_guest_page(vcpu->kvm, vsie_page->riccbd_gpa, hpa);
688                 vsie_page->riccbd_gpa = 0;
689                 scb_s->riccbd = 0;
690         }
691 
692         hpa = scb_s->sdnxo;
693         if (hpa) {
694                 unpin_guest_page(vcpu->kvm, vsie_page->sdnx_gpa, hpa);
695                 vsie_page->sdnx_gpa = 0;
696                 scb_s->sdnxo = 0;
697         }
698 }
699 
700 /*
701  * Instead of shadowing some blocks, we can simply forward them because the
702  * addresses in the scb are 64 bit long.
703  *
704  * This works as long as the data lies in one page. If blocks ever exceed one
705  * page, we have to fall back to shadowing.
706  *
707  * As we reuse the sca, the vcpu pointers contained in it are invalid. We must
708  * therefore not enable any facilities that access these pointers (e.g. SIGPIF).
709  *
710  * Returns: - 0 if all blocks were pinned.
711  *          - > 0 if control has to be given to guest 2
712  *          - -ENOMEM if out of memory
713  */
714 static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
715 {
716         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
717         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
718         hpa_t hpa;
719         gpa_t gpa;
720         int rc = 0;
721 
722         gpa = READ_ONCE(scb_o->scaol) & ~0xfUL;
723         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
724                 gpa |= (u64) READ_ONCE(scb_o->scaoh) << 32;
725         if (gpa) {
726                 if (gpa < 2 * PAGE_SIZE)
727                         rc = set_validity_icpt(scb_s, 0x0038U);
728                 else if ((gpa & ~0x1fffUL) == kvm_s390_get_prefix(vcpu))
729                         rc = set_validity_icpt(scb_s, 0x0011U);
730                 else if ((gpa & PAGE_MASK) !=
731                          ((gpa + sizeof(struct bsca_block) - 1) & PAGE_MASK))
732                         rc = set_validity_icpt(scb_s, 0x003bU);
733                 if (!rc) {
734                         rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
735                         if (rc)
736                                 rc = set_validity_icpt(scb_s, 0x0034U);
737                 }
738                 if (rc)
739                         goto unpin;
740                 vsie_page->sca_gpa = gpa;
741                 scb_s->scaoh = (u32)((u64)hpa >> 32);
742                 scb_s->scaol = (u32)(u64)hpa;
743         }
744 
745         gpa = READ_ONCE(scb_o->itdba) & ~0xffUL;
746         if (gpa && (scb_s->ecb & ECB_TE)) {
747                 if (gpa < 2 * PAGE_SIZE) {
748                         rc = set_validity_icpt(scb_s, 0x0080U);
749                         goto unpin;
750                 }
751                 /* 256 bytes cannot cross page boundaries */
752                 rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
753                 if (rc) {
754                         rc = set_validity_icpt(scb_s, 0x0080U);
755                         goto unpin;
756                 }
757                 vsie_page->itdba_gpa = gpa;
758                 scb_s->itdba = hpa;
759         }
760 
761         gpa = READ_ONCE(scb_o->gvrd) & ~0x1ffUL;
762         if (gpa && (scb_s->eca & ECA_VX) && !(scb_s->ecd & ECD_HOSTREGMGMT)) {
763                 if (gpa < 2 * PAGE_SIZE) {
764                         rc = set_validity_icpt(scb_s, 0x1310U);
765                         goto unpin;
766                 }
767                 /*
768                  * 512 bytes vector registers cannot cross page boundaries
769                  * if this block gets bigger, we have to shadow it.
770                  */
771                 rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
772                 if (rc) {
773                         rc = set_validity_icpt(scb_s, 0x1310U);
774                         goto unpin;
775                 }
776                 vsie_page->gvrd_gpa = gpa;
777                 scb_s->gvrd = hpa;
778         }
779 
780         gpa = READ_ONCE(scb_o->riccbd) & ~0x3fUL;
781         if (gpa && (scb_s->ecb3 & ECB3_RI)) {
782                 if (gpa < 2 * PAGE_SIZE) {
783                         rc = set_validity_icpt(scb_s, 0x0043U);
784                         goto unpin;
785                 }
786                 /* 64 bytes cannot cross page boundaries */
787                 rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
788                 if (rc) {
789                         rc = set_validity_icpt(scb_s, 0x0043U);
790                         goto unpin;
791                 }
792                 /* Validity 0x0044 will be checked by SIE */
793                 vsie_page->riccbd_gpa = gpa;
794                 scb_s->riccbd = hpa;
795         }
796         if (((scb_s->ecb & ECB_GS) && !(scb_s->ecd & ECD_HOSTREGMGMT)) ||
797             (scb_s->ecd & ECD_ETOKENF)) {
798                 unsigned long sdnxc;
799 
800                 gpa = READ_ONCE(scb_o->sdnxo) & ~0xfUL;
801                 sdnxc = READ_ONCE(scb_o->sdnxo) & 0xfUL;
802                 if (!gpa || gpa < 2 * PAGE_SIZE) {
803                         rc = set_validity_icpt(scb_s, 0x10b0U);
804                         goto unpin;
805                 }
806                 if (sdnxc < 6 || sdnxc > 12) {
807                         rc = set_validity_icpt(scb_s, 0x10b1U);
808                         goto unpin;
809                 }
810                 if (gpa & ((1 << sdnxc) - 1)) {
811                         rc = set_validity_icpt(scb_s, 0x10b2U);
812                         goto unpin;
813                 }
814                 /* Due to alignment rules (checked above) this cannot
815                  * cross page boundaries
816                  */
817                 rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
818                 if (rc) {
819                         rc = set_validity_icpt(scb_s, 0x10b0U);
820                         goto unpin;
821                 }
822                 vsie_page->sdnx_gpa = gpa;
823                 scb_s->sdnxo = hpa | sdnxc;
824         }
825         return 0;
826 unpin:
827         unpin_blocks(vcpu, vsie_page);
828         return rc;
829 }
830 
831 /* unpin the scb provided by guest 2, marking it as dirty */
832 static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
833                       gpa_t gpa)
834 {
835         hpa_t hpa = (hpa_t) vsie_page->scb_o;
836 
837         if (hpa)
838                 unpin_guest_page(vcpu->kvm, gpa, hpa);
839         vsie_page->scb_o = NULL;
840 }
841 
842 /*
843  * Pin the scb at gpa provided by guest 2 at vsie_page->scb_o.
844  *
845  * Returns: - 0 if the scb was pinned.
846  *          - > 0 if control has to be given to guest 2
847  */
848 static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
849                    gpa_t gpa)
850 {
851         hpa_t hpa;
852         int rc;
853 
854         rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
855         if (rc) {
856                 rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
857                 WARN_ON_ONCE(rc);
858                 return 1;
859         }
860         vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa;
861         return 0;
862 }
863 
864 /*
865  * Inject a fault into guest 2.
866  *
867  * Returns: - > 0 if control has to be given to guest 2
868  *            < 0 if an error occurred during injection.
869  */
870 static int inject_fault(struct kvm_vcpu *vcpu, __u16 code, __u64 vaddr,
871                         bool write_flag)
872 {
873         struct kvm_s390_pgm_info pgm = {
874                 .code = code,
875                 .trans_exc_code =
876                         /* 0-51: virtual address */
877                         (vaddr & 0xfffffffffffff000UL) |
878                         /* 52-53: store / fetch */
879                         (((unsigned int) !write_flag) + 1) << 10,
880                         /* 62-63: asce id (alway primary == 0) */
881                 .exc_access_id = 0, /* always primary */
882                 .op_access_id = 0, /* not MVPG */
883         };
884         int rc;
885 
886         if (code == PGM_PROTECTION)
887                 pgm.trans_exc_code |= 0x4UL;
888 
889         rc = kvm_s390_inject_prog_irq(vcpu, &pgm);
890         return rc ? rc : 1;
891 }
892 
893 /*
894  * Handle a fault during vsie execution on a gmap shadow.
895  *
896  * Returns: - 0 if the fault was resolved
897  *          - > 0 if control has to be given to guest 2
898  *          - < 0 if an error occurred
899  */
900 static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
901 {
902         int rc;
903 
904         if (current->thread.gmap_int_code == PGM_PROTECTION)
905                 /* we can directly forward all protection exceptions */
906                 return inject_fault(vcpu, PGM_PROTECTION,
907                                     current->thread.gmap_addr, 1);
908 
909         rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
910                                    current->thread.gmap_addr);
911         if (rc > 0) {
912                 rc = inject_fault(vcpu, rc,
913                                   current->thread.gmap_addr,
914                                   current->thread.gmap_write_flag);
915                 if (rc >= 0)
916                         vsie_page->fault_addr = current->thread.gmap_addr;
917         }
918         return rc;
919 }
920 
921 /*
922  * Retry the previous fault that required guest 2 intervention. This avoids
923  * one superfluous SIE re-entry and direct exit.
924  *
925  * Will ignore any errors. The next SIE fault will do proper fault handling.
926  */
927 static void handle_last_fault(struct kvm_vcpu *vcpu,
928                               struct vsie_page *vsie_page)
929 {
930         if (vsie_page->fault_addr)
931                 kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
932                                       vsie_page->fault_addr);
933         vsie_page->fault_addr = 0;
934 }
935 
936 static inline void clear_vsie_icpt(struct vsie_page *vsie_page)
937 {
938         vsie_page->scb_s.icptcode = 0;
939 }
940 
941 /* rewind the psw and clear the vsie icpt, so we can retry execution */
942 static void retry_vsie_icpt(struct vsie_page *vsie_page)
943 {
944         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
945         int ilen = insn_length(scb_s->ipa >> 8);
946 
947         /* take care of EXECUTE instructions */
948         if (scb_s->icptstatus & 1) {
949                 ilen = (scb_s->icptstatus >> 4) & 0x6;
950                 if (!ilen)
951                         ilen = 4;
952         }
953         scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, ilen);
954         clear_vsie_icpt(vsie_page);
955 }
956 
957 /*
958  * Try to shadow + enable the guest 2 provided facility list.
959  * Retry instruction execution if enabled for and provided by guest 2.
960  *
961  * Returns: - 0 if handled (retry or guest 2 icpt)
962  *          - > 0 if control has to be given to guest 2
963  */
964 static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
965 {
966         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
967         __u32 fac = READ_ONCE(vsie_page->scb_o->fac) & 0x7ffffff8U;
968 
969         if (fac && test_kvm_facility(vcpu->kvm, 7)) {
970                 retry_vsie_icpt(vsie_page);
971                 if (read_guest_real(vcpu, fac, &vsie_page->fac,
972                                     sizeof(vsie_page->fac)))
973                         return set_validity_icpt(scb_s, 0x1090U);
974                 scb_s->fac = (__u32)(__u64) &vsie_page->fac;
975         }
976         return 0;
977 }
978 
979 /*
980  * Run the vsie on a shadow scb and a shadow gmap, without any further
981  * sanity checks, handling SIE faults.
982  *
983  * Returns: - 0 everything went fine
984  *          - > 0 if control has to be given to guest 2
985  *          - < 0 if an error occurred
986  */
987 static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
988         __releases(vcpu->kvm->srcu)
989         __acquires(vcpu->kvm->srcu)
990 {
991         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
992         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
993         int guest_bp_isolation;
994         int rc = 0;
995 
996         handle_last_fault(vcpu, vsie_page);
997 
998         if (need_resched())
999                 schedule();
1000         if (test_cpu_flag(CIF_MCCK_PENDING))
1001                 s390_handle_mcck();
1002 
1003         srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
1004 
1005         /* save current guest state of bp isolation override */
1006         guest_bp_isolation = test_thread_flag(TIF_ISOLATE_BP_GUEST);
1007 
1008         /*
1009          * The guest is running with BPBC, so we have to force it on for our
1010          * nested guest. This is done by enabling BPBC globally, so the BPBC
1011          * control in the SCB (which the nested guest can modify) is simply
1012          * ignored.
1013          */
1014         if (test_kvm_facility(vcpu->kvm, 82) &&
1015             vcpu->arch.sie_block->fpf & FPF_BPBC)
1016                 set_thread_flag(TIF_ISOLATE_BP_GUEST);
1017 
1018         local_irq_disable();
1019         guest_enter_irqoff();
1020         local_irq_enable();
1021 
1022         /*
1023          * Simulate a SIE entry of the VCPU (see sie64a), so VCPU blocking
1024          * and VCPU requests also hinder the vSIE from running and lead
1025          * to an immediate exit. kvm_s390_vsie_kick() has to be used to
1026          * also kick the vSIE.
1027          */
1028         vcpu->arch.sie_block->prog0c |= PROG_IN_SIE;
1029         barrier();
1030         if (!kvm_s390_vcpu_sie_inhibited(vcpu))
1031                 rc = sie64a(scb_s, vcpu->run->s.regs.gprs);
1032         barrier();
1033         vcpu->arch.sie_block->prog0c &= ~PROG_IN_SIE;
1034 
1035         local_irq_disable();
1036         guest_exit_irqoff();
1037         local_irq_enable();
1038 
1039         /* restore guest state for bp isolation override */
1040         if (!guest_bp_isolation)
1041                 clear_thread_flag(TIF_ISOLATE_BP_GUEST);
1042 
1043         vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
1044 
1045         if (rc == -EINTR) {
1046                 VCPU_EVENT(vcpu, 3, "%s", "machine check");
1047                 kvm_s390_reinject_machine_check(vcpu, &vsie_page->mcck_info);
1048                 return 0;
1049         }
1050 
1051         if (rc > 0)
1052                 rc = 0; /* we could still have an icpt */
1053         else if (rc == -EFAULT)
1054                 return handle_fault(vcpu, vsie_page);
1055 
1056         switch (scb_s->icptcode) {
1057         case ICPT_INST:
1058                 if (scb_s->ipa == 0xb2b0)
1059                         rc = handle_stfle(vcpu, vsie_page);
1060                 break;
1061         case ICPT_STOP:
1062                 /* stop not requested by g2 - must have been a kick */
1063                 if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT))
1064                         clear_vsie_icpt(vsie_page);
1065                 break;
1066         case ICPT_VALIDITY:
1067                 if ((scb_s->ipa & 0xf000) != 0xf000)
1068                         scb_s->ipa += 0x1000;
1069                 break;
1070         }
1071         return rc;
1072 }
1073 
1074 static void release_gmap_shadow(struct vsie_page *vsie_page)
1075 {
1076         if (vsie_page->gmap)
1077                 gmap_put(vsie_page->gmap);
1078         WRITE_ONCE(vsie_page->gmap, NULL);
1079         prefix_unmapped(vsie_page);
1080 }
1081 
1082 static int acquire_gmap_shadow(struct kvm_vcpu *vcpu,
1083                                struct vsie_page *vsie_page)
1084 {
1085         unsigned long asce;
1086         union ctlreg0 cr0;
1087         struct gmap *gmap;
1088         int edat;
1089 
1090         asce = vcpu->arch.sie_block->gcr[1];
1091         cr0.val = vcpu->arch.sie_block->gcr[0];
1092         edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
1093         edat += edat && test_kvm_facility(vcpu->kvm, 78);
1094 
1095         /*
1096          * ASCE or EDAT could have changed since last icpt, or the gmap
1097          * we're holding has been unshadowed. If the gmap is still valid,
1098          * we can safely reuse it.
1099          */
1100         if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat))
1101                 return 0;
1102 
1103         /* release the old shadow - if any, and mark the prefix as unmapped */
1104         release_gmap_shadow(vsie_page);
1105         gmap = gmap_shadow(vcpu->arch.gmap, asce, edat);
1106         if (IS_ERR(gmap))
1107                 return PTR_ERR(gmap);
1108         gmap->private = vcpu->kvm;
1109         WRITE_ONCE(vsie_page->gmap, gmap);
1110         return 0;
1111 }
1112 
1113 /*
1114  * Register the shadow scb at the VCPU, e.g. for kicking out of vsie.
1115  */
1116 static void register_shadow_scb(struct kvm_vcpu *vcpu,
1117                                 struct vsie_page *vsie_page)
1118 {
1119         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
1120 
1121         WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);
1122         /*
1123          * External calls have to lead to a kick of the vcpu and
1124          * therefore the vsie -> Simulate Wait state.
1125          */
1126         kvm_s390_set_cpuflags(vcpu, CPUSTAT_WAIT);
1127         /*
1128          * We have to adjust the g3 epoch by the g2 epoch. The epoch will
1129          * automatically be adjusted on tod clock changes via kvm_sync_clock.
1130          */
1131         preempt_disable();
1132         scb_s->epoch += vcpu->kvm->arch.epoch;
1133 
1134         if (scb_s->ecd & ECD_MEF) {
1135                 scb_s->epdx += vcpu->kvm->arch.epdx;
1136                 if (scb_s->epoch < vcpu->kvm->arch.epoch)
1137                         scb_s->epdx += 1;
1138         }
1139 
1140         preempt_enable();
1141 }
1142 
1143 /*
1144  * Unregister a shadow scb from a VCPU.
1145  */
1146 static void unregister_shadow_scb(struct kvm_vcpu *vcpu)
1147 {
1148         kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT);
1149         WRITE_ONCE(vcpu->arch.vsie_block, NULL);
1150 }
1151 
1152 /*
1153  * Run the vsie on a shadowed scb, managing the gmap shadow, handling
1154  * prefix pages and faults.
1155  *
1156  * Returns: - 0 if no errors occurred
1157  *          - > 0 if control has to be given to guest 2
1158  *          - -ENOMEM if out of memory
1159  */
1160 static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
1161 {
1162         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
1163         int rc = 0;
1164 
1165         while (1) {
1166                 rc = acquire_gmap_shadow(vcpu, vsie_page);
1167                 if (!rc)
1168                         rc = map_prefix(vcpu, vsie_page);
1169                 if (!rc) {
1170                         gmap_enable(vsie_page->gmap);
1171                         update_intervention_requests(vsie_page);
1172                         rc = do_vsie_run(vcpu, vsie_page);
1173                         gmap_enable(vcpu->arch.gmap);
1174                 }
1175                 atomic_andnot(PROG_BLOCK_SIE, &scb_s->prog20);
1176 
1177                 if (rc == -EAGAIN)
1178                         rc = 0;
1179                 if (rc || scb_s->icptcode || signal_pending(current) ||
1180                     kvm_s390_vcpu_has_irq(vcpu, 0) ||
1181                     kvm_s390_vcpu_sie_inhibited(vcpu))
1182                         break;
1183         }
1184 
1185         if (rc == -EFAULT) {
1186                 /*
1187                  * Addressing exceptions are always presentes as intercepts.
1188                  * As addressing exceptions are suppressing and our guest 3 PSW
1189                  * points at the responsible instruction, we have to
1190                  * forward the PSW and set the ilc. If we can't read guest 3
1191                  * instruction, we can use an arbitrary ilc. Let's always use
1192                  * ilen = 4 for now, so we can avoid reading in guest 3 virtual
1193                  * memory. (we could also fake the shadow so the hardware
1194                  * handles it).
1195                  */
1196                 scb_s->icptcode = ICPT_PROGI;
1197                 scb_s->iprcc = PGM_ADDRESSING;
1198                 scb_s->pgmilc = 4;
1199                 scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4);
1200         }
1201         return rc;
1202 }
1203 
1204 /*
1205  * Get or create a vsie page for a scb address.
1206  *
1207  * Returns: - address of a vsie page (cached or new one)
1208  *          - NULL if the same scb address is already used by another VCPU
1209  *          - ERR_PTR(-ENOMEM) if out of memory
1210  */
1211 static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
1212 {
1213         struct vsie_page *vsie_page;
1214         struct page *page;
1215         int nr_vcpus;
1216 
1217         rcu_read_lock();
1218         page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);
1219         rcu_read_unlock();
1220         if (page) {
1221                 if (page_ref_inc_return(page) == 2)
1222                         return page_to_virt(page);
1223                 page_ref_dec(page);
1224         }
1225 
1226         /*
1227          * We want at least #online_vcpus shadows, so every VCPU can execute
1228          * the VSIE in parallel.
1229          */
1230         nr_vcpus = atomic_read(&kvm->online_vcpus);
1231 
1232         mutex_lock(&kvm->arch.vsie.mutex);
1233         if (kvm->arch.vsie.page_count < nr_vcpus) {
1234                 page = alloc_page(GFP_KERNEL | __GFP_ZERO | GFP_DMA);
1235                 if (!page) {
1236                         mutex_unlock(&kvm->arch.vsie.mutex);
1237                         return ERR_PTR(-ENOMEM);
1238                 }
1239                 page_ref_inc(page);
1240                 kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page;
1241                 kvm->arch.vsie.page_count++;
1242         } else {
1243                 /* reuse an existing entry that belongs to nobody */
1244                 while (true) {
1245                         page = kvm->arch.vsie.pages[kvm->arch.vsie.next];
1246                         if (page_ref_inc_return(page) == 2)
1247                                 break;
1248                         page_ref_dec(page);
1249                         kvm->arch.vsie.next++;
1250                         kvm->arch.vsie.next %= nr_vcpus;
1251                 }
1252                 radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
1253         }
1254         page->index = addr;
1255         /* double use of the same address */
1256         if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) {
1257                 page_ref_dec(page);
1258                 mutex_unlock(&kvm->arch.vsie.mutex);
1259                 return NULL;
1260         }
1261         mutex_unlock(&kvm->arch.vsie.mutex);
1262 
1263         vsie_page = page_to_virt(page);
1264         memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block));
1265         release_gmap_shadow(vsie_page);
1266         vsie_page->fault_addr = 0;
1267         vsie_page->scb_s.ihcpu = 0xffffU;
1268         return vsie_page;
1269 }
1270 
1271 /* put a vsie page acquired via get_vsie_page */
1272 static void put_vsie_page(struct kvm *kvm, struct vsie_page *vsie_page)
1273 {
1274         struct page *page = pfn_to_page(__pa(vsie_page) >> PAGE_SHIFT);
1275 
1276         page_ref_dec(page);
1277 }
1278 
1279 int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
1280 {
1281         struct vsie_page *vsie_page;
1282         unsigned long scb_addr;
1283         int rc;
1284 
1285         vcpu->stat.instruction_sie++;
1286         if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIEF2))
1287                 return -EOPNOTSUPP;
1288         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
1289                 return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
1290 
1291         BUILD_BUG_ON(sizeof(struct vsie_page) != PAGE_SIZE);
1292         scb_addr = kvm_s390_get_base_disp_s(vcpu, NULL);
1293 
1294         /* 512 byte alignment */
1295         if (unlikely(scb_addr & 0x1ffUL))
1296                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
1297 
1298         if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0) ||
1299             kvm_s390_vcpu_sie_inhibited(vcpu))
1300                 return 0;
1301 
1302         vsie_page = get_vsie_page(vcpu->kvm, scb_addr);
1303         if (IS_ERR(vsie_page))
1304                 return PTR_ERR(vsie_page);
1305         else if (!vsie_page)
1306                 /* double use of sie control block - simply do nothing */
1307                 return 0;
1308 
1309         rc = pin_scb(vcpu, vsie_page, scb_addr);
1310         if (rc)
1311                 goto out_put;
1312         rc = shadow_scb(vcpu, vsie_page);
1313         if (rc)
1314                 goto out_unpin_scb;
1315         rc = pin_blocks(vcpu, vsie_page);
1316         if (rc)
1317                 goto out_unshadow;
1318         register_shadow_scb(vcpu, vsie_page);
1319         rc = vsie_run(vcpu, vsie_page);
1320         unregister_shadow_scb(vcpu);
1321         unpin_blocks(vcpu, vsie_page);
1322 out_unshadow:
1323         unshadow_scb(vcpu, vsie_page);
1324 out_unpin_scb:
1325         unpin_scb(vcpu, vsie_page, scb_addr);
1326 out_put:
1327         put_vsie_page(vcpu->kvm, vsie_page);
1328 
1329         return rc < 0 ? rc : 0;
1330 }
1331 
1332 /* Init the vsie data structures. To be called when a vm is initialized. */
1333 void kvm_s390_vsie_init(struct kvm *kvm)
1334 {
1335         mutex_init(&kvm->arch.vsie.mutex);
1336         INIT_RADIX_TREE(&kvm->arch.vsie.addr_to_page, GFP_KERNEL);
1337 }
1338 
1339 /* Destroy the vsie data structures. To be called when a vm is destroyed. */
1340 void kvm_s390_vsie_destroy(struct kvm *kvm)
1341 {
1342         struct vsie_page *vsie_page;
1343         struct page *page;
1344         int i;
1345 
1346         mutex_lock(&kvm->arch.vsie.mutex);
1347         for (i = 0; i < kvm->arch.vsie.page_count; i++) {
1348                 page = kvm->arch.vsie.pages[i];
1349                 kvm->arch.vsie.pages[i] = NULL;
1350                 vsie_page = page_to_virt(page);
1351                 release_gmap_shadow(vsie_page);
1352                 /* free the radix tree entry */
1353                 radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
1354                 __free_page(page);
1355         }
1356         kvm->arch.vsie.page_count = 0;
1357         mutex_unlock(&kvm->arch.vsie.mutex);
1358 }
1359 
1360 void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu)
1361 {
1362         struct kvm_s390_sie_block *scb = READ_ONCE(vcpu->arch.vsie_block);
1363 
1364         /*
1365          * Even if the VCPU lets go of the shadow sie block reference, it is
1366          * still valid in the cache. So we can safely kick it.
1367          */
1368         if (scb) {
1369                 atomic_or(PROG_BLOCK_SIE, &scb->prog20);
1370                 if (scb->prog0c & PROG_IN_SIE)
1371                         atomic_or(CPUSTAT_STOP_INT, &scb->cpuflags);
1372         }
1373 }
1374 

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