arch/s390/kvm/vsie.c

   1 /*
   2  * kvm nested virtualization support for s390x
   3  *
   4  * Copyright IBM Corp. 2016
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License (version 2 only)
   8  * as published by the Free Software Foundation.
   9  *
  10  *    Author(s): David Hildenbrand <dahi@linux.vnet.ibm.com>
  11  */
  12 #include <linux/vmalloc.h>
  13 #include <linux/kvm_host.h>
  14 #include <linux/bug.h>
  15 #include <linux/list.h>
  16 #include <linux/bitmap.h>
  17 #include <asm/gmap.h>
  18 #include <asm/mmu_context.h>
  19 #include <asm/sclp.h>
  20 #include <asm/nmi.h>
  21 #include <asm/dis.h>
  22 #include "kvm-s390.h"
  23 #include "gaccess.h"
  24
  25 struct vsie_page {
  26         struct kvm_s390_sie_block scb_s;        /* 0x0000 */
  27         /* the pinned originial scb */
  28         struct kvm_s390_sie_block *scb_o;       /* 0x0200 */
  29         /* the shadow gmap in use by the vsie_page */
  30         struct gmap *gmap;                      /* 0x0208 */
  31         /* address of the last reported fault to guest2 */
  32         unsigned long fault_addr;               /* 0x0210 */
  33         __u8 reserved[0x0700 - 0x0218];         /* 0x0218 */
  34         struct kvm_s390_crypto_cb crycb;        /* 0x0700 */
  35         __u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE]; /* 0x0800 */
  36 } __packed;
  37
  38 /* trigger a validity icpt for the given scb */
  39 static int set_validity_icpt(struct kvm_s390_sie_block *scb,
  40                              __u16 reason_code)
  41 {
  42         scb->ipa = 0x1000;
  43         scb->ipb = ((__u32) reason_code) << 16;
  44         scb->icptcode = ICPT_VALIDITY;
  45         return 1;
  46 }
  47
  48 /* mark the prefix as unmapped, this will block the VSIE */
  49 static void prefix_unmapped(struct vsie_page *vsie_page)
  50 {
  51         atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20);
  52 }
  53
  54 /* mark the prefix as unmapped and wait until the VSIE has been left */
  55 static void prefix_unmapped_sync(struct vsie_page *vsie_page)
  56 {
  57         prefix_unmapped(vsie_page);
  58         if (vsie_page->scb_s.prog0c & PROG_IN_SIE)
  59                 atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags);
  60         while (vsie_page->scb_s.prog0c & PROG_IN_SIE)
  61                 cpu_relax();
  62 }
  63
  64 /* mark the prefix as mapped, this will allow the VSIE to run */
  65 static void prefix_mapped(struct vsie_page *vsie_page)
  66 {
  67         atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20);
  68 }
  69
  70 /* test if the prefix is mapped into the gmap shadow */
  71 static int prefix_is_mapped(struct vsie_page *vsie_page)
  72 {
  73         return !(atomic_read(&vsie_page->scb_s.prog20) & PROG_REQUEST);
  74 }
  75
  76 /* copy the updated intervention request bits into the shadow scb */
  77 static void update_intervention_requests(struct vsie_page *vsie_page)
  78 {
  79         const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT;
  80         int cpuflags;
  81
  82         cpuflags = atomic_read(&vsie_page->scb_o->cpuflags);
  83         atomic_andnot(bits, &vsie_page->scb_s.cpuflags);
  84         atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags);
  85 }
  86
  87 /* shadow (filter and validate) the cpuflags  */
  88 static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
  89 {
  90         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
  91         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
  92         int newflags, cpuflags = atomic_read(&scb_o->cpuflags);
  93
  94         /* we don't allow ESA/390 guests */
  95         if (!(cpuflags & CPUSTAT_ZARCH))
  96                 return set_validity_icpt(scb_s, 0x0001U);
  97
  98         if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS))
  99                 return set_validity_icpt(scb_s, 0x0001U);
 100         else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR))
 101                 return set_validity_icpt(scb_s, 0x0007U);
 102
 103         /* intervention requests will be set later */
 104         newflags = CPUSTAT_ZARCH;
 105         if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8))
 106                 newflags |= CPUSTAT_GED;
 107         if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) {
 108                 if (cpuflags & CPUSTAT_GED)
 109                         return set_validity_icpt(scb_s, 0x0001U);
 110                 newflags |= CPUSTAT_GED2;
 111         }
 112         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GPERE))
 113                 newflags |= cpuflags & CPUSTAT_P;
 114         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GSLS))
 115                 newflags |= cpuflags & CPUSTAT_SM;
 116         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IBS))
 117                 newflags |= cpuflags & CPUSTAT_IBS;
 118
 119         atomic_set(&scb_s->cpuflags, newflags);
 120         return 0;
 121 }
 122
 123 /*
 124  * Create a shadow copy of the crycb block and setup key wrapping, if
 125  * requested for guest 3 and enabled for guest 2.
 126  *
 127  * We only accept format-1 (no AP in g2), but convert it into format-2
 128  * There is nothing to do for format-0.
 129  *
 130  * Returns: - 0 if shadowed or nothing to do
 131  *          - > 0 if control has to be given to guest 2
 132  */
 133 static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 134 {
 135         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 136         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
 137         u32 crycb_addr = scb_o->crycbd & 0x7ffffff8U;
 138         unsigned long *b1, *b2;
 139         u8 ecb3_flags;
 140
 141         scb_s->crycbd = 0;
 142         if (!(scb_o->crycbd & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1))
 143                 return 0;
 144         /* format-1 is supported with message-security-assist extension 3 */
 145         if (!test_kvm_facility(vcpu->kvm, 76))
 146                 return 0;
 147         /* we may only allow it if enabled for guest 2 */
 148         ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
 149                      (ECB3_AES | ECB3_DEA);
 150         if (!ecb3_flags)
 151                 return 0;
 152
 153         if ((crycb_addr & PAGE_MASK) != ((crycb_addr + 128) & PAGE_MASK))
 154                 return set_validity_icpt(scb_s, 0x003CU);
 155         else if (!crycb_addr)
 156                 return set_validity_icpt(scb_s, 0x0039U);
 157
 158         /* copy only the wrapping keys */
 159         if (read_guest_real(vcpu, crycb_addr + 72, &vsie_page->crycb, 56))
 160                 return set_validity_icpt(scb_s, 0x0035U);
 161
 162         scb_s->ecb3 |= ecb3_flags;
 163         scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT1 |
 164                         CRYCB_FORMAT2;
 165
 166         /* xor both blocks in one run */
 167         b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask;
 168         b2 = (unsigned long *)
 169                             vcpu->kvm->arch.crypto.crycb->dea_wrapping_key_mask;
 170         /* as 56%8 == 0, bitmap_xor won't overwrite any data */
 171         bitmap_xor(b1, b1, b2, BITS_PER_BYTE * 56);
 172         return 0;
 173 }
 174
 175 /* shadow (round up/down) the ibc to avoid validity icpt */
 176 static void prepare_ibc(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 177 {
 178         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 179         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
 180         __u64 min_ibc = (sclp.ibc >> 16) & 0x0fffU;
 181
 182         scb_s->ibc = 0;
 183         /* ibc installed in g2 and requested for g3 */
 184         if (vcpu->kvm->arch.model.ibc && (scb_o->ibc & 0x0fffU)) {
 185                 scb_s->ibc = scb_o->ibc & 0x0fffU;
 186                 /* takte care of the minimum ibc level of the machine */
 187                 if (scb_s->ibc < min_ibc)
 188                         scb_s->ibc = min_ibc;
 189                 /* take care of the maximum ibc level set for the guest */
 190                 if (scb_s->ibc > vcpu->kvm->arch.model.ibc)
 191                         scb_s->ibc = vcpu->kvm->arch.model.ibc;
 192         }
 193 }
 194
 195 /* unshadow the scb, copying parameters back to the real scb */
 196 static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 197 {
 198         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 199         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
 200
 201         /* interception */
 202         scb_o->icptcode = scb_s->icptcode;
 203         scb_o->icptstatus = scb_s->icptstatus;
 204         scb_o->ipa = scb_s->ipa;
 205         scb_o->ipb = scb_s->ipb;
 206         scb_o->gbea = scb_s->gbea;
 207
 208         /* timer */
 209         scb_o->cputm = scb_s->cputm;
 210         scb_o->ckc = scb_s->ckc;
 211         scb_o->todpr = scb_s->todpr;
 212
 213         /* guest state */
 214         scb_o->gpsw = scb_s->gpsw;
 215         scb_o->gg14 = scb_s->gg14;
 216         scb_o->gg15 = scb_s->gg15;
 217         memcpy(scb_o->gcr, scb_s->gcr, 128);
 218         scb_o->pp = scb_s->pp;
 219
 220         /* interrupt intercept */
 221         switch (scb_s->icptcode) {
 222         case ICPT_PROGI:
 223         case ICPT_INSTPROGI:
 224         case ICPT_EXTINT:
 225                 memcpy((void *)((u64)scb_o + 0xc0),
 226                        (void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0);
 227                 break;
 228         case ICPT_PARTEXEC:
 229                 /* MVPG only */
 230                 memcpy((void *)((u64)scb_o + 0xc0),
 231                        (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0);
 232                 break;
 233         }
 234
 235         if (scb_s->ihcpu != 0xffffU)
 236                 scb_o->ihcpu = scb_s->ihcpu;
 237 }
 238
 239 /*
 240  * Setup the shadow scb by copying and checking the relevant parts of the g2
 241  * provided scb.
 242  *
 243  * Returns: - 0 if the scb has been shadowed
 244  *          - > 0 if control has to be given to guest 2
 245  */
 246 static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 247 {
 248         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
 249         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 250         bool had_tx = scb_s->ecb & 0x10U;
 251         unsigned long new_mso = 0;
 252         int rc;
 253
 254         /* make sure we don't have any leftovers when reusing the scb */
 255         scb_s->icptcode = 0;
 256         scb_s->eca = 0;
 257         scb_s->ecb = 0;
 258         scb_s->ecb2 = 0;
 259         scb_s->ecb3 = 0;
 260         scb_s->ecd = 0;
 261         scb_s->fac = 0;
 262
 263         rc = prepare_cpuflags(vcpu, vsie_page);
 264         if (rc)
 265                 goto out;
 266
 267         /* timer */
 268         scb_s->cputm = scb_o->cputm;
 269         scb_s->ckc = scb_o->ckc;
 270         scb_s->todpr = scb_o->todpr;
 271         scb_s->epoch = scb_o->epoch;
 272
 273         /* guest state */
 274         scb_s->gpsw = scb_o->gpsw;
 275         scb_s->gg14 = scb_o->gg14;
 276         scb_s->gg15 = scb_o->gg15;
 277         memcpy(scb_s->gcr, scb_o->gcr, 128);
 278         scb_s->pp = scb_o->pp;
 279
 280         /* interception / execution handling */
 281         scb_s->gbea = scb_o->gbea;
 282         scb_s->lctl = scb_o->lctl;
 283         scb_s->svcc = scb_o->svcc;
 284         scb_s->ictl = scb_o->ictl;
 285         /*
 286          * SKEY handling functions can't deal with false setting of PTE invalid
 287          * bits. Therefore we cannot provide interpretation and would later
 288          * have to provide own emulation handlers.
 289          */
 290         scb_s->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
 291         scb_s->icpua = scb_o->icpua;
 292
 293         if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_SM))
 294                 new_mso = scb_o->mso & 0xfffffffffff00000UL;
 295         /* if the hva of the prefix changes, we have to remap the prefix */
 296         if (scb_s->mso != new_mso || scb_s->prefix != scb_o->prefix)
 297                 prefix_unmapped(vsie_page);
 298          /* SIE will do mso/msl validity and exception checks for us */
 299         scb_s->msl = scb_o->msl & 0xfffffffffff00000UL;
 300         scb_s->mso = new_mso;
 301         scb_s->prefix = scb_o->prefix;
 302
 303         /* We have to definetly flush the tlb if this scb never ran */
 304         if (scb_s->ihcpu != 0xffffU)
 305                 scb_s->ihcpu = scb_o->ihcpu;
 306
 307         /* MVPG and Protection Exception Interpretation are always available */
 308         scb_s->eca |= scb_o->eca & 0x01002000U;
 309         /* Host-protection-interruption introduced with ESOP */
 310         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_ESOP))
 311                 scb_s->ecb |= scb_o->ecb & 0x02U;
 312         /* transactional execution */
 313         if (test_kvm_facility(vcpu->kvm, 73)) {
 314                 /* remap the prefix is tx is toggled on */
 315                 if ((scb_o->ecb & 0x10U) && !had_tx)
 316                         prefix_unmapped(vsie_page);
 317                 scb_s->ecb |= scb_o->ecb & 0x10U;
 318         }
 319         /* SIMD */
 320         if (test_kvm_facility(vcpu->kvm, 129)) {
 321                 scb_s->eca |= scb_o->eca & 0x00020000U;
 322                 scb_s->ecd |= scb_o->ecd & 0x20000000U;
 323         }
 324         /* Run-time-Instrumentation */
 325         if (test_kvm_facility(vcpu->kvm, 64))
 326                 scb_s->ecb3 |= scb_o->ecb3 & 0x01U;
 327         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIIF))
 328                 scb_s->eca |= scb_o->eca & 0x00000001U;
 329         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IB))
 330                 scb_s->eca |= scb_o->eca & 0x40000000U;
 331         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI))
 332                 scb_s->eca |= scb_o->eca & 0x80000000U;
 333
 334         prepare_ibc(vcpu, vsie_page);
 335         rc = shadow_crycb(vcpu, vsie_page);
 336 out:
 337         if (rc)
 338                 unshadow_scb(vcpu, vsie_page);
 339         return rc;
 340 }
 341
 342 void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
 343                                  unsigned long end)
 344 {
 345         struct kvm *kvm = gmap->private;
 346         struct vsie_page *cur;
 347         unsigned long prefix;
 348         struct page *page;
 349         int i;
 350
 351         if (!gmap_is_shadow(gmap))
 352                 return;
 353         if (start >= 1UL << 31)
 354                 /* We are only interested in prefix pages */
 355                 return;
 356
 357         /*
 358          * Only new shadow blocks are added to the list during runtime,
 359          * therefore we can safely reference them all the time.
 360          */
 361         for (i = 0; i < kvm->arch.vsie.page_count; i++) {
 362                 page = READ_ONCE(kvm->arch.vsie.pages[i]);
 363                 if (!page)
 364                         continue;
 365                 cur = page_to_virt(page);
 366                 if (READ_ONCE(cur->gmap) != gmap)
 367                         continue;
 368                 prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT;
 369                 /* with mso/msl, the prefix lies at an offset */
 370                 prefix += cur->scb_s.mso;
 371                 if (prefix <= end && start <= prefix + 2 * PAGE_SIZE - 1)
 372                         prefix_unmapped_sync(cur);
 373         }
 374 }
 375
 376 /*
 377  * Map the first prefix page and if tx is enabled also the second prefix page.
 378  *
 379  * The prefix will be protected, a gmap notifier will inform about unmaps.
 380  * The shadow scb must not be executed until the prefix is remapped, this is
 381  * guaranteed by properly handling PROG_REQUEST.
 382  *
 383  * Returns: - 0 on if successfully mapped or already mapped
 384  *          - > 0 if control has to be given to guest 2
 385  *          - -EAGAIN if the caller can retry immediately
 386  *          - -ENOMEM if out of memory
 387  */
 388 static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 389 {
 390         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 391         u64 prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
 392         int rc;
 393
 394         if (prefix_is_mapped(vsie_page))
 395                 return 0;
 396
 397         /* mark it as mapped so we can catch any concurrent unmappers */
 398         prefix_mapped(vsie_page);
 399
 400         /* with mso/msl, the prefix lies at offset *mso* */
 401         prefix += scb_s->mso;
 402
 403         rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix);
 404         if (!rc && (scb_s->ecb & 0x10U))
 405                 rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
 406                                            prefix + PAGE_SIZE);
 407         /*
 408          * We don't have to mprotect, we will be called for all unshadows.
 409          * SIE will detect if protection applies and trigger a validity.
 410          */
 411         if (rc)
 412                 prefix_unmapped(vsie_page);
 413         if (rc > 0 || rc == -EFAULT)
 414                 rc = set_validity_icpt(scb_s, 0x0037U);
 415         return rc;
 416 }
 417
 418 /*
 419  * Pin the guest page given by gpa and set hpa to the pinned host address.
 420  * Will always be pinned writable.
 421  *
 422  * Returns: - 0 on success
 423  *          - -EINVAL if the gpa is not valid guest storage
 424  *          - -ENOMEM if out of memory
 425  */
 426 static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa)
 427 {
 428         struct page *page;
 429         hva_t hva;
 430         int rc;
 431
 432         hva = gfn_to_hva(kvm, gpa_to_gfn(gpa));
 433         if (kvm_is_error_hva(hva))
 434                 return -EINVAL;
 435         rc = get_user_pages_fast(hva, 1, 1, &page);
 436         if (rc < 0)
 437                 return rc;
 438         else if (rc != 1)
 439                 return -ENOMEM;
 440         *hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK);
 441         return 0;
 442 }
 443
 444 /* Unpins a page previously pinned via pin_guest_page, marking it as dirty. */
 445 static void unpin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t hpa)
 446 {
 447         struct page *page;
 448
 449         page = virt_to_page(hpa);
 450         set_page_dirty_lock(page);
 451         put_page(page);
 452         /* mark the page always as dirty for migration */
 453         mark_page_dirty(kvm, gpa_to_gfn(gpa));
 454 }
 455
 456 /* unpin all blocks previously pinned by pin_blocks(), marking them dirty */
 457 static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 458 {
 459         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
 460         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 461         hpa_t hpa;
 462         gpa_t gpa;
 463
 464         hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol;
 465         if (hpa) {
 466                 gpa = scb_o->scaol & ~0xfUL;
 467                 if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
 468                         gpa |= (u64) scb_o->scaoh << 32;
 469                 unpin_guest_page(vcpu->kvm, gpa, hpa);
 470                 scb_s->scaol = 0;
 471                 scb_s->scaoh = 0;
 472         }
 473
 474         hpa = scb_s->itdba;
 475         if (hpa) {
 476                 gpa = scb_o->itdba & ~0xffUL;
 477                 unpin_guest_page(vcpu->kvm, gpa, hpa);
 478                 scb_s->itdba = 0;
 479         }
 480
 481         hpa = scb_s->gvrd;
 482         if (hpa) {
 483                 gpa = scb_o->gvrd & ~0x1ffUL;
 484                 unpin_guest_page(vcpu->kvm, gpa, hpa);
 485                 scb_s->gvrd = 0;
 486         }
 487
 488         hpa = scb_s->riccbd;
 489         if (hpa) {
 490                 gpa = scb_o->riccbd & ~0x3fUL;
 491                 unpin_guest_page(vcpu->kvm, gpa, hpa);
 492                 scb_s->riccbd = 0;
 493         }
 494 }
 495
 496 /*
 497  * Instead of shadowing some blocks, we can simply forward them because the
 498  * addresses in the scb are 64 bit long.
 499  *
 500  * This works as long as the data lies in one page. If blocks ever exceed one
 501  * page, we have to fall back to shadowing.
 502  *
 503  * As we reuse the sca, the vcpu pointers contained in it are invalid. We must
 504  * therefore not enable any facilities that access these pointers (e.g. SIGPIF).
 505  *
 506  * Returns: - 0 if all blocks were pinned.
 507  *          - > 0 if control has to be given to guest 2
 508  *          - -ENOMEM if out of memory
 509  */
 510 static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 511 {
 512         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
 513         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 514         hpa_t hpa;
 515         gpa_t gpa;
 516         int rc = 0;
 517
 518         gpa = scb_o->scaol & ~0xfUL;
 519         if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
 520                 gpa |= (u64) scb_o->scaoh << 32;
 521         if (gpa) {
 522                 if (!(gpa & ~0x1fffUL))
 523                         rc = set_validity_icpt(scb_s, 0x0038U);
 524                 else if ((gpa & ~0x1fffUL) == kvm_s390_get_prefix(vcpu))
 525                         rc = set_validity_icpt(scb_s, 0x0011U);
 526                 else if ((gpa & PAGE_MASK) !=
 527                          ((gpa + sizeof(struct bsca_block) - 1) & PAGE_MASK))
 528                         rc = set_validity_icpt(scb_s, 0x003bU);
 529                 if (!rc) {
 530                         rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
 531                         if (rc == -EINVAL)
 532                                 rc = set_validity_icpt(scb_s, 0x0034U);
 533                 }
 534                 if (rc)
 535                         goto unpin;
 536                 scb_s->scaoh = (u32)((u64)hpa >> 32);
 537                 scb_s->scaol = (u32)(u64)hpa;
 538         }
 539
 540         gpa = scb_o->itdba & ~0xffUL;
 541         if (gpa && (scb_s->ecb & 0x10U)) {
 542                 if (!(gpa & ~0x1fffU)) {
 543                         rc = set_validity_icpt(scb_s, 0x0080U);
 544                         goto unpin;
 545                 }
 546                 /* 256 bytes cannot cross page boundaries */
 547                 rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
 548                 if (rc == -EINVAL)
 549                         rc = set_validity_icpt(scb_s, 0x0080U);
 550                 if (rc)
 551                         goto unpin;
 552                 scb_s->itdba = hpa;
 553         }
 554
 555         gpa = scb_o->gvrd & ~0x1ffUL;
 556         if (gpa && (scb_s->eca & 0x00020000U) &&
 557             !(scb_s->ecd & 0x20000000U)) {
 558                 if (!(gpa & ~0x1fffUL)) {
 559                         rc = set_validity_icpt(scb_s, 0x1310U);
 560                         goto unpin;
 561                 }
 562                 /*
 563                  * 512 bytes vector registers cannot cross page boundaries
 564                  * if this block gets bigger, we have to shadow it.
 565                  */
 566                 rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
 567                 if (rc == -EINVAL)
 568                         rc = set_validity_icpt(scb_s, 0x1310U);
 569                 if (rc)
 570                         goto unpin;
 571                 scb_s->gvrd = hpa;
 572         }
 573
 574         gpa = scb_o->riccbd & ~0x3fUL;
 575         if (gpa && (scb_s->ecb3 & 0x01U)) {
 576                 if (!(gpa & ~0x1fffUL)) {
 577                         rc = set_validity_icpt(scb_s, 0x0043U);
 578                         goto unpin;
 579                 }
 580                 /* 64 bytes cannot cross page boundaries */
 581                 rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
 582                 if (rc == -EINVAL)
 583                         rc = set_validity_icpt(scb_s, 0x0043U);
 584                 /* Validity 0x0044 will be checked by SIE */
 585                 if (rc)
 586                         goto unpin;
 587                 scb_s->riccbd = hpa;
 588         }
 589         return 0;
 590 unpin:
 591         unpin_blocks(vcpu, vsie_page);
 592         return rc;
 593 }
 594
 595 /* unpin the scb provided by guest 2, marking it as dirty */
 596 static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
 597                       gpa_t gpa)
 598 {
 599         hpa_t hpa = (hpa_t) vsie_page->scb_o;
 600
 601         if (hpa)
 602                 unpin_guest_page(vcpu->kvm, gpa, hpa);
 603         vsie_page->scb_o = NULL;
 604 }
 605
 606 /*
 607  * Pin the scb at gpa provided by guest 2 at vsie_page->scb_o.
 608  *
 609  * Returns: - 0 if the scb was pinned.
 610  *          - > 0 if control has to be given to guest 2
 611  *          - -ENOMEM if out of memory
 612  */
 613 static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
 614                    gpa_t gpa)
 615 {
 616         hpa_t hpa;
 617         int rc;
 618
 619         rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
 620         if (rc == -EINVAL) {
 621                 rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 622                 if (!rc)
 623                         rc = 1;
 624         }
 625         if (!rc)
 626                 vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa;
 627         return rc;
 628 }
 629
 630 /*
 631  * Inject a fault into guest 2.
 632  *
 633  * Returns: - > 0 if control has to be given to guest 2
 634  *            < 0 if an error occurred during injection.
 635  */
 636 static int inject_fault(struct kvm_vcpu *vcpu, __u16 code, __u64 vaddr,
 637                         bool write_flag)
 638 {
 639         struct kvm_s390_pgm_info pgm = {
 640                 .code = code,
 641                 .trans_exc_code =
 642                         /* 0-51: virtual address */
 643                         (vaddr & 0xfffffffffffff000UL) |
 644                         /* 52-53: store / fetch */
 645                         (((unsigned int) !write_flag) + 1) << 10,
 646                         /* 62-63: asce id (alway primary == 0) */
 647                 .exc_access_id = 0, /* always primary */
 648                 .op_access_id = 0, /* not MVPG */
 649         };
 650         int rc;
 651
 652         if (code == PGM_PROTECTION)
 653                 pgm.trans_exc_code |= 0x4UL;
 654
 655         rc = kvm_s390_inject_prog_irq(vcpu, &pgm);
 656         return rc ? rc : 1;
 657 }
 658
 659 /*
 660  * Handle a fault during vsie execution on a gmap shadow.
 661  *
 662  * Returns: - 0 if the fault was resolved
 663  *          - > 0 if control has to be given to guest 2
 664  *          - < 0 if an error occurred
 665  */
 666 static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 667 {
 668         int rc;
 669
 670         if (current->thread.gmap_int_code == PGM_PROTECTION)
 671                 /* we can directly forward all protection exceptions */
 672                 return inject_fault(vcpu, PGM_PROTECTION,
 673                                     current->thread.gmap_addr, 1);
 674
 675         rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
 676                                    current->thread.gmap_addr);
 677         if (rc > 0) {
 678                 rc = inject_fault(vcpu, rc,
 679                                   current->thread.gmap_addr,
 680                                   current->thread.gmap_write_flag);
 681                 if (rc >= 0)
 682                         vsie_page->fault_addr = current->thread.gmap_addr;
 683         }
 684         return rc;
 685 }
 686
 687 /*
 688  * Retry the previous fault that required guest 2 intervention. This avoids
 689  * one superfluous SIE re-entry and direct exit.
 690  *
 691  * Will ignore any errors. The next SIE fault will do proper fault handling.
 692  */
 693 static void handle_last_fault(struct kvm_vcpu *vcpu,
 694                               struct vsie_page *vsie_page)
 695 {
 696         if (vsie_page->fault_addr)
 697                 kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
 698                                       vsie_page->fault_addr);
 699         vsie_page->fault_addr = 0;
 700 }
 701
 702 static inline void clear_vsie_icpt(struct vsie_page *vsie_page)
 703 {
 704         vsie_page->scb_s.icptcode = 0;
 705 }
 706
 707 /* rewind the psw and clear the vsie icpt, so we can retry execution */
 708 static void retry_vsie_icpt(struct vsie_page *vsie_page)
 709 {
 710         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 711         int ilen = insn_length(scb_s->ipa >> 8);
 712
 713         /* take care of EXECUTE instructions */
 714         if (scb_s->icptstatus & 1) {
 715                 ilen = (scb_s->icptstatus >> 4) & 0x6;
 716                 if (!ilen)
 717                         ilen = 4;
 718         }
 719         scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, ilen);
 720         clear_vsie_icpt(vsie_page);
 721 }
 722
 723 /*
 724  * Try to shadow + enable the guest 2 provided facility list.
 725  * Retry instruction execution if enabled for and provided by guest 2.
 726  *
 727  * Returns: - 0 if handled (retry or guest 2 icpt)
 728  *          - > 0 if control has to be given to guest 2
 729  */
 730 static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 731 {
 732         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 733         __u32 fac = vsie_page->scb_o->fac & 0x7ffffff8U;
 734
 735         if (fac && test_kvm_facility(vcpu->kvm, 7)) {
 736                 retry_vsie_icpt(vsie_page);
 737                 if (read_guest_real(vcpu, fac, &vsie_page->fac,
 738                                     sizeof(vsie_page->fac)))
 739                         return set_validity_icpt(scb_s, 0x1090U);
 740                 scb_s->fac = (__u32)(__u64) &vsie_page->fac;
 741         }
 742         return 0;
 743 }
 744
 745 /*
 746  * Run the vsie on a shadow scb and a shadow gmap, without any further
 747  * sanity checks, handling SIE faults.
 748  *
 749  * Returns: - 0 everything went fine
 750  *          - > 0 if control has to be given to guest 2
 751  *          - < 0 if an error occurred
 752  */
 753 static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 754 {
 755         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 756         struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
 757         int rc;
 758
 759         handle_last_fault(vcpu, vsie_page);
 760
 761         if (need_resched())
 762                 schedule();
 763         if (test_cpu_flag(CIF_MCCK_PENDING))
 764                 s390_handle_mcck();
 765
 766         srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
 767         local_irq_disable();
 768         guest_enter_irqoff();
 769         local_irq_enable();
 770
 771         rc = sie64a(scb_s, vcpu->run->s.regs.gprs);
 772
 773         local_irq_disable();
 774         guest_exit_irqoff();
 775         local_irq_enable();
 776         vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
 777
 778         if (rc > 0)
 779                 rc = 0; /* we could still have an icpt */
 780         else if (rc == -EFAULT)
 781                 return handle_fault(vcpu, vsie_page);
 782
 783         switch (scb_s->icptcode) {
 784         case ICPT_INST:
 785                 if (scb_s->ipa == 0xb2b0)
 786                         rc = handle_stfle(vcpu, vsie_page);
 787                 break;
 788         case ICPT_STOP:
 789                 /* stop not requested by g2 - must have been a kick */
 790                 if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT))
 791                         clear_vsie_icpt(vsie_page);
 792                 break;
 793         case ICPT_VALIDITY:
 794                 if ((scb_s->ipa & 0xf000) != 0xf000)
 795                         scb_s->ipa += 0x1000;
 796                 break;
 797         }
 798         return rc;
 799 }
 800
 801 static void release_gmap_shadow(struct vsie_page *vsie_page)
 802 {
 803         if (vsie_page->gmap)
 804                 gmap_put(vsie_page->gmap);
 805         WRITE_ONCE(vsie_page->gmap, NULL);
 806         prefix_unmapped(vsie_page);
 807 }
 808
 809 static int acquire_gmap_shadow(struct kvm_vcpu *vcpu,
 810                                struct vsie_page *vsie_page)
 811 {
 812         unsigned long asce;
 813         union ctlreg0 cr0;
 814         struct gmap *gmap;
 815         int edat;
 816
 817         asce = vcpu->arch.sie_block->gcr[1];
 818         cr0.val = vcpu->arch.sie_block->gcr[0];
 819         edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
 820         edat += edat && test_kvm_facility(vcpu->kvm, 78);
 821
 822         /*
 823          * ASCE or EDAT could have changed since last icpt, or the gmap
 824          * we're holding has been unshadowed. If the gmap is still valid,
 825          * we can safely reuse it.
 826          */
 827         if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat))
 828                 return 0;
 829
 830         /* release the old shadow - if any, and mark the prefix as unmapped */
 831         release_gmap_shadow(vsie_page);
 832         gmap = gmap_shadow(vcpu->arch.gmap, asce, edat);
 833         if (IS_ERR(gmap))
 834                 return PTR_ERR(gmap);
 835         gmap->private = vcpu->kvm;
 836         WRITE_ONCE(vsie_page->gmap, gmap);
 837         return 0;
 838 }
 839
 840 /*
 841  * Register the shadow scb at the VCPU, e.g. for kicking out of vsie.
 842  */
 843 static void register_shadow_scb(struct kvm_vcpu *vcpu,
 844                                 struct vsie_page *vsie_page)
 845 {
 846         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 847
 848         WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);
 849         /*
 850          * External calls have to lead to a kick of the vcpu and
 851          * therefore the vsie -> Simulate Wait state.
 852          */
 853         atomic_or(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
 854         /*
 855          * We have to adjust the g3 epoch by the g2 epoch. The epoch will
 856          * automatically be adjusted on tod clock changes via kvm_sync_clock.
 857          */
 858         preempt_disable();
 859         scb_s->epoch += vcpu->kvm->arch.epoch;
 860         preempt_enable();
 861 }
 862
 863 /*
 864  * Unregister a shadow scb from a VCPU.
 865  */
 866 static void unregister_shadow_scb(struct kvm_vcpu *vcpu)
 867 {
 868         atomic_andnot(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
 869         WRITE_ONCE(vcpu->arch.vsie_block, NULL);
 870 }
 871
 872 /*
 873  * Run the vsie on a shadowed scb, managing the gmap shadow, handling
 874  * prefix pages and faults.
 875  *
 876  * Returns: - 0 if no errors occurred
 877  *          - > 0 if control has to be given to guest 2
 878  *          - -ENOMEM if out of memory
 879  */
 880 static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 881 {
 882         struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
 883         int rc = 0;
 884
 885         while (1) {
 886                 rc = acquire_gmap_shadow(vcpu, vsie_page);
 887                 if (!rc)
 888                         rc = map_prefix(vcpu, vsie_page);
 889                 if (!rc) {
 890                         gmap_enable(vsie_page->gmap);
 891                         update_intervention_requests(vsie_page);
 892                         rc = do_vsie_run(vcpu, vsie_page);
 893                         gmap_enable(vcpu->arch.gmap);
 894                 }
 895                 atomic_andnot(PROG_BLOCK_SIE, &scb_s->prog20);
 896
 897                 if (rc == -EAGAIN)
 898                         rc = 0;
 899                 if (rc || scb_s->icptcode || signal_pending(current) ||
 900                     kvm_s390_vcpu_has_irq(vcpu, 0))
 901                         break;
 902         };
 903
 904         if (rc == -EFAULT) {
 905                 /*
 906                  * Addressing exceptions are always presentes as intercepts.
 907                  * As addressing exceptions are suppressing and our guest 3 PSW
 908                  * points at the responsible instruction, we have to
 909                  * forward the PSW and set the ilc. If we can't read guest 3
 910                  * instruction, we can use an arbitrary ilc. Let's always use
 911                  * ilen = 4 for now, so we can avoid reading in guest 3 virtual
 912                  * memory. (we could also fake the shadow so the hardware
 913                  * handles it).
 914                  */
 915                 scb_s->icptcode = ICPT_PROGI;
 916                 scb_s->iprcc = PGM_ADDRESSING;
 917                 scb_s->pgmilc = 4;
 918                 scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4);
 919         }
 920         return rc;
 921 }
 922
 923 /*
 924  * Get or create a vsie page for a scb address.
 925  *
 926  * Returns: - address of a vsie page (cached or new one)
 927  *          - NULL if the same scb address is already used by another VCPU
 928  *          - ERR_PTR(-ENOMEM) if out of memory
 929  */
 930 static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
 931 {
 932         struct vsie_page *vsie_page;
 933         struct page *page;
 934         int nr_vcpus;
 935
 936         rcu_read_lock();
 937         page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);
 938         rcu_read_unlock();
 939         if (page) {
 940                 if (page_ref_inc_return(page) == 2)
 941                         return page_to_virt(page);
 942                 page_ref_dec(page);
 943         }
 944
 945         /*
 946          * We want at least #online_vcpus shadows, so every VCPU can execute
 947          * the VSIE in parallel.
 948          */
 949         nr_vcpus = atomic_read(&kvm->online_vcpus);
 950
 951         mutex_lock(&kvm->arch.vsie.mutex);
 952         if (kvm->arch.vsie.page_count < nr_vcpus) {
 953                 page = alloc_page(GFP_KERNEL | __GFP_ZERO | GFP_DMA);
 954                 if (!page) {
 955                         mutex_unlock(&kvm->arch.vsie.mutex);
 956                         return ERR_PTR(-ENOMEM);
 957                 }
 958                 page_ref_inc(page);
 959                 kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page;
 960                 kvm->arch.vsie.page_count++;
 961         } else {
 962                 /* reuse an existing entry that belongs to nobody */
 963                 while (true) {
 964                         page = kvm->arch.vsie.pages[kvm->arch.vsie.next];
 965                         if (page_ref_inc_return(page) == 2)
 966                                 break;
 967                         page_ref_dec(page);
 968                         kvm->arch.vsie.next++;
 969                         kvm->arch.vsie.next %= nr_vcpus;
 970                 }
 971                 radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
 972         }
 973         page->index = addr;
 974         /* double use of the same address */
 975         if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) {
 976                 page_ref_dec(page);
 977                 mutex_unlock(&kvm->arch.vsie.mutex);
 978                 return NULL;
 979         }
 980         mutex_unlock(&kvm->arch.vsie.mutex);
 981
 982         vsie_page = page_to_virt(page);
 983         memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block));
 984         release_gmap_shadow(vsie_page);
 985         vsie_page->fault_addr = 0;
 986         vsie_page->scb_s.ihcpu = 0xffffU;
 987         return vsie_page;
 988 }
 989
 990 /* put a vsie page acquired via get_vsie_page */
 991 static void put_vsie_page(struct kvm *kvm, struct vsie_page *vsie_page)
 992 {
 993         struct page *page = pfn_to_page(__pa(vsie_page) >> PAGE_SHIFT);
 994
 995         page_ref_dec(page);
 996 }
 997
 998 int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
 999 {
1000         struct vsie_page *vsie_page;
1001         unsigned long scb_addr;
1002         int rc;
1003
1004         vcpu->stat.instruction_sie++;
1005         if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIEF2))
1006                 return -EOPNOTSUPP;
1007         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
1008                 return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
1009
1010         BUILD_BUG_ON(sizeof(struct vsie_page) != 4096);
1011         scb_addr = kvm_s390_get_base_disp_s(vcpu, NULL);
1012
1013         /* 512 byte alignment */
1014         if (unlikely(scb_addr & 0x1ffUL))
1015                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
1016
1017         if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0))
1018                 return 0;
1019
1020         vsie_page = get_vsie_page(vcpu->kvm, scb_addr);
1021         if (IS_ERR(vsie_page))
1022                 return PTR_ERR(vsie_page);
1023         else if (!vsie_page)
1024                 /* double use of sie control block - simply do nothing */
1025                 return 0;
1026
1027         rc = pin_scb(vcpu, vsie_page, scb_addr);
1028         if (rc)
1029                 goto out_put;
1030         rc = shadow_scb(vcpu, vsie_page);
1031         if (rc)
1032                 goto out_unpin_scb;
1033         rc = pin_blocks(vcpu, vsie_page);
1034         if (rc)
1035                 goto out_unshadow;
1036         register_shadow_scb(vcpu, vsie_page);
1037         rc = vsie_run(vcpu, vsie_page);
1038         unregister_shadow_scb(vcpu);
1039         unpin_blocks(vcpu, vsie_page);
1040 out_unshadow:
1041         unshadow_scb(vcpu, vsie_page);
1042 out_unpin_scb:
1043         unpin_scb(vcpu, vsie_page, scb_addr);
1044 out_put:
1045         put_vsie_page(vcpu->kvm, vsie_page);
1046
1047         return rc < 0 ? rc : 0;
1048 }
1049
1050 /* Init the vsie data structures. To be called when a vm is initialized. */
1051 void kvm_s390_vsie_init(struct kvm *kvm)
1052 {
1053         mutex_init(&kvm->arch.vsie.mutex);
1054         INIT_RADIX_TREE(&kvm->arch.vsie.addr_to_page, GFP_KERNEL);
1055 }
1056
1057 /* Destroy the vsie data structures. To be called when a vm is destroyed. */
1058 void kvm_s390_vsie_destroy(struct kvm *kvm)
1059 {
1060         struct vsie_page *vsie_page;
1061         struct page *page;
1062         int i;
1063
1064         mutex_lock(&kvm->arch.vsie.mutex);
1065         for (i = 0; i < kvm->arch.vsie.page_count; i++) {
1066                 page = kvm->arch.vsie.pages[i];
1067                 kvm->arch.vsie.pages[i] = NULL;
1068                 vsie_page = page_to_virt(page);
1069                 release_gmap_shadow(vsie_page);
1070                 /* free the radix tree entry */
1071                 radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
1072                 __free_page(page);
1073         }
1074         kvm->arch.vsie.page_count = 0;
1075         mutex_unlock(&kvm->arch.vsie.mutex);
1076 }
1077
1078 void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu)
1079 {
1080         struct kvm_s390_sie_block *scb = READ_ONCE(vcpu->arch.vsie_block);
1081
1082         /*
1083          * Even if the VCPU lets go of the shadow sie block reference, it is
1084          * still valid in the cache. So we can safely kick it.
1085          */
1086         if (scb) {
1087                 atomic_or(PROG_BLOCK_SIE, &scb->prog20);
1088                 if (scb->prog0c & PROG_IN_SIE)
1089                         atomic_or(CPUSTAT_STOP_INT, &scb->cpuflags);
1090         }
1091 }