David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 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 "kvm-s390.h" |
| 22 | #include "gaccess.h" |
| 23 | |
| 24 | struct vsie_page { |
| 25 | struct kvm_s390_sie_block scb_s; /* 0x0000 */ |
| 26 | /* the pinned originial scb */ |
| 27 | struct kvm_s390_sie_block *scb_o; /* 0x0200 */ |
| 28 | /* the shadow gmap in use by the vsie_page */ |
| 29 | struct gmap *gmap; /* 0x0208 */ |
| 30 | __u8 reserved[0x1000 - 0x0210]; /* 0x0210 */ |
| 31 | } __packed; |
| 32 | |
| 33 | /* trigger a validity icpt for the given scb */ |
| 34 | static int set_validity_icpt(struct kvm_s390_sie_block *scb, |
| 35 | __u16 reason_code) |
| 36 | { |
| 37 | scb->ipa = 0x1000; |
| 38 | scb->ipb = ((__u32) reason_code) << 16; |
| 39 | scb->icptcode = ICPT_VALIDITY; |
| 40 | return 1; |
| 41 | } |
| 42 | |
| 43 | /* mark the prefix as unmapped, this will block the VSIE */ |
| 44 | static void prefix_unmapped(struct vsie_page *vsie_page) |
| 45 | { |
| 46 | atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20); |
| 47 | } |
| 48 | |
| 49 | /* mark the prefix as unmapped and wait until the VSIE has been left */ |
| 50 | static void prefix_unmapped_sync(struct vsie_page *vsie_page) |
| 51 | { |
| 52 | prefix_unmapped(vsie_page); |
| 53 | if (vsie_page->scb_s.prog0c & PROG_IN_SIE) |
| 54 | atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags); |
| 55 | while (vsie_page->scb_s.prog0c & PROG_IN_SIE) |
| 56 | cpu_relax(); |
| 57 | } |
| 58 | |
| 59 | /* mark the prefix as mapped, this will allow the VSIE to run */ |
| 60 | static void prefix_mapped(struct vsie_page *vsie_page) |
| 61 | { |
| 62 | atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20); |
| 63 | } |
| 64 | |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 65 | /* test if the prefix is mapped into the gmap shadow */ |
| 66 | static int prefix_is_mapped(struct vsie_page *vsie_page) |
| 67 | { |
| 68 | return !(atomic_read(&vsie_page->scb_s.prog20) & PROG_REQUEST); |
| 69 | } |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 70 | |
| 71 | /* copy the updated intervention request bits into the shadow scb */ |
| 72 | static void update_intervention_requests(struct vsie_page *vsie_page) |
| 73 | { |
| 74 | const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT; |
| 75 | int cpuflags; |
| 76 | |
| 77 | cpuflags = atomic_read(&vsie_page->scb_o->cpuflags); |
| 78 | atomic_andnot(bits, &vsie_page->scb_s.cpuflags); |
| 79 | atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags); |
| 80 | } |
| 81 | |
| 82 | /* shadow (filter and validate) the cpuflags */ |
| 83 | static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 84 | { |
| 85 | struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; |
| 86 | struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; |
| 87 | int newflags, cpuflags = atomic_read(&scb_o->cpuflags); |
| 88 | |
| 89 | /* we don't allow ESA/390 guests */ |
| 90 | if (!(cpuflags & CPUSTAT_ZARCH)) |
| 91 | return set_validity_icpt(scb_s, 0x0001U); |
| 92 | |
| 93 | if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS)) |
| 94 | return set_validity_icpt(scb_s, 0x0001U); |
| 95 | else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR)) |
| 96 | return set_validity_icpt(scb_s, 0x0007U); |
| 97 | |
| 98 | /* intervention requests will be set later */ |
| 99 | newflags = CPUSTAT_ZARCH; |
| 100 | |
| 101 | atomic_set(&scb_s->cpuflags, newflags); |
| 102 | return 0; |
| 103 | } |
| 104 | |
David Hildenbrand | 3573602 | 2016-02-19 10:11:24 +0100 | [diff] [blame^] | 105 | /* shadow (round up/down) the ibc to avoid validity icpt */ |
| 106 | static void prepare_ibc(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 107 | { |
| 108 | struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; |
| 109 | struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; |
| 110 | __u64 min_ibc = (sclp.ibc >> 16) & 0x0fffU; |
| 111 | |
| 112 | scb_s->ibc = 0; |
| 113 | /* ibc installed in g2 and requested for g3 */ |
| 114 | if (vcpu->kvm->arch.model.ibc && (scb_o->ibc & 0x0fffU)) { |
| 115 | scb_s->ibc = scb_o->ibc & 0x0fffU; |
| 116 | /* takte care of the minimum ibc level of the machine */ |
| 117 | if (scb_s->ibc < min_ibc) |
| 118 | scb_s->ibc = min_ibc; |
| 119 | /* take care of the maximum ibc level set for the guest */ |
| 120 | if (scb_s->ibc > vcpu->kvm->arch.model.ibc) |
| 121 | scb_s->ibc = vcpu->kvm->arch.model.ibc; |
| 122 | } |
| 123 | } |
| 124 | |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 125 | /* unshadow the scb, copying parameters back to the real scb */ |
| 126 | static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 127 | { |
| 128 | struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; |
| 129 | struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; |
| 130 | |
| 131 | /* interception */ |
| 132 | scb_o->icptcode = scb_s->icptcode; |
| 133 | scb_o->icptstatus = scb_s->icptstatus; |
| 134 | scb_o->ipa = scb_s->ipa; |
| 135 | scb_o->ipb = scb_s->ipb; |
| 136 | scb_o->gbea = scb_s->gbea; |
| 137 | |
| 138 | /* timer */ |
| 139 | scb_o->cputm = scb_s->cputm; |
| 140 | scb_o->ckc = scb_s->ckc; |
| 141 | scb_o->todpr = scb_s->todpr; |
| 142 | |
| 143 | /* guest state */ |
| 144 | scb_o->gpsw = scb_s->gpsw; |
| 145 | scb_o->gg14 = scb_s->gg14; |
| 146 | scb_o->gg15 = scb_s->gg15; |
| 147 | memcpy(scb_o->gcr, scb_s->gcr, 128); |
| 148 | scb_o->pp = scb_s->pp; |
| 149 | |
| 150 | /* interrupt intercept */ |
| 151 | switch (scb_s->icptcode) { |
| 152 | case ICPT_PROGI: |
| 153 | case ICPT_INSTPROGI: |
| 154 | case ICPT_EXTINT: |
| 155 | memcpy((void *)((u64)scb_o + 0xc0), |
| 156 | (void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0); |
| 157 | break; |
| 158 | case ICPT_PARTEXEC: |
| 159 | /* MVPG only */ |
| 160 | memcpy((void *)((u64)scb_o + 0xc0), |
| 161 | (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0); |
| 162 | break; |
| 163 | } |
| 164 | |
| 165 | if (scb_s->ihcpu != 0xffffU) |
| 166 | scb_o->ihcpu = scb_s->ihcpu; |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * Setup the shadow scb by copying and checking the relevant parts of the g2 |
| 171 | * provided scb. |
| 172 | * |
| 173 | * Returns: - 0 if the scb has been shadowed |
| 174 | * - > 0 if control has to be given to guest 2 |
| 175 | */ |
| 176 | static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 177 | { |
| 178 | struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; |
| 179 | struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 180 | unsigned long new_mso; |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 181 | int rc; |
| 182 | |
| 183 | /* make sure we don't have any leftovers when reusing the scb */ |
| 184 | scb_s->icptcode = 0; |
| 185 | scb_s->eca = 0; |
| 186 | scb_s->ecb = 0; |
| 187 | scb_s->ecb2 = 0; |
| 188 | scb_s->ecb3 = 0; |
| 189 | scb_s->ecd = 0; |
| 190 | |
| 191 | rc = prepare_cpuflags(vcpu, vsie_page); |
| 192 | if (rc) |
| 193 | goto out; |
| 194 | |
| 195 | /* timer */ |
| 196 | scb_s->cputm = scb_o->cputm; |
| 197 | scb_s->ckc = scb_o->ckc; |
| 198 | scb_s->todpr = scb_o->todpr; |
| 199 | scb_s->epoch = scb_o->epoch; |
| 200 | |
| 201 | /* guest state */ |
| 202 | scb_s->gpsw = scb_o->gpsw; |
| 203 | scb_s->gg14 = scb_o->gg14; |
| 204 | scb_s->gg15 = scb_o->gg15; |
| 205 | memcpy(scb_s->gcr, scb_o->gcr, 128); |
| 206 | scb_s->pp = scb_o->pp; |
| 207 | |
| 208 | /* interception / execution handling */ |
| 209 | scb_s->gbea = scb_o->gbea; |
| 210 | scb_s->lctl = scb_o->lctl; |
| 211 | scb_s->svcc = scb_o->svcc; |
| 212 | scb_s->ictl = scb_o->ictl; |
| 213 | /* |
| 214 | * SKEY handling functions can't deal with false setting of PTE invalid |
| 215 | * bits. Therefore we cannot provide interpretation and would later |
| 216 | * have to provide own emulation handlers. |
| 217 | */ |
| 218 | scb_s->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE; |
| 219 | scb_s->icpua = scb_o->icpua; |
| 220 | |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 221 | new_mso = scb_o->mso & 0xfffffffffff00000UL; |
| 222 | /* if the hva of the prefix changes, we have to remap the prefix */ |
| 223 | if (scb_s->mso != new_mso || scb_s->prefix != scb_o->prefix) |
| 224 | prefix_unmapped(vsie_page); |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 225 | /* SIE will do mso/msl validity and exception checks for us */ |
| 226 | scb_s->msl = scb_o->msl & 0xfffffffffff00000UL; |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 227 | scb_s->mso = new_mso; |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 228 | scb_s->prefix = scb_o->prefix; |
| 229 | |
| 230 | /* We have to definetly flush the tlb if this scb never ran */ |
| 231 | if (scb_s->ihcpu != 0xffffU) |
| 232 | scb_s->ihcpu = scb_o->ihcpu; |
| 233 | |
| 234 | /* MVPG and Protection Exception Interpretation are always available */ |
| 235 | scb_s->eca |= scb_o->eca & 0x01002000U; |
| 236 | |
David Hildenbrand | 3573602 | 2016-02-19 10:11:24 +0100 | [diff] [blame^] | 237 | prepare_ibc(vcpu, vsie_page); |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 238 | out: |
| 239 | if (rc) |
| 240 | unshadow_scb(vcpu, vsie_page); |
| 241 | return rc; |
| 242 | } |
| 243 | |
| 244 | void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start, |
| 245 | unsigned long end) |
| 246 | { |
| 247 | struct kvm *kvm = gmap->private; |
| 248 | struct vsie_page *cur; |
| 249 | unsigned long prefix; |
| 250 | struct page *page; |
| 251 | int i; |
| 252 | |
| 253 | if (!gmap_is_shadow(gmap)) |
| 254 | return; |
| 255 | if (start >= 1UL << 31) |
| 256 | /* We are only interested in prefix pages */ |
| 257 | return; |
| 258 | |
| 259 | /* |
| 260 | * Only new shadow blocks are added to the list during runtime, |
| 261 | * therefore we can safely reference them all the time. |
| 262 | */ |
| 263 | for (i = 0; i < kvm->arch.vsie.page_count; i++) { |
| 264 | page = READ_ONCE(kvm->arch.vsie.pages[i]); |
| 265 | if (!page) |
| 266 | continue; |
| 267 | cur = page_to_virt(page); |
| 268 | if (READ_ONCE(cur->gmap) != gmap) |
| 269 | continue; |
| 270 | prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT; |
| 271 | /* with mso/msl, the prefix lies at an offset */ |
| 272 | prefix += cur->scb_s.mso; |
| 273 | if (prefix <= end && start <= prefix + PAGE_SIZE - 1) |
| 274 | prefix_unmapped_sync(cur); |
| 275 | } |
| 276 | } |
| 277 | |
| 278 | /* |
| 279 | * Map the first prefix page. |
| 280 | * |
| 281 | * The prefix will be protected, a gmap notifier will inform about unmaps. |
| 282 | * The shadow scb must not be executed until the prefix is remapped, this is |
| 283 | * guaranteed by properly handling PROG_REQUEST. |
| 284 | * |
| 285 | * Returns: - 0 on if successfully mapped or already mapped |
| 286 | * - > 0 if control has to be given to guest 2 |
| 287 | * - -EAGAIN if the caller can retry immediately |
| 288 | * - -ENOMEM if out of memory |
| 289 | */ |
| 290 | static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 291 | { |
| 292 | struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; |
| 293 | u64 prefix = scb_s->prefix << GUEST_PREFIX_SHIFT; |
| 294 | int rc; |
| 295 | |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 296 | if (prefix_is_mapped(vsie_page)) |
| 297 | return 0; |
| 298 | |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 299 | /* mark it as mapped so we can catch any concurrent unmappers */ |
| 300 | prefix_mapped(vsie_page); |
| 301 | |
| 302 | /* with mso/msl, the prefix lies at offset *mso* */ |
| 303 | prefix += scb_s->mso; |
| 304 | |
| 305 | rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix); |
| 306 | /* |
| 307 | * We don't have to mprotect, we will be called for all unshadows. |
| 308 | * SIE will detect if protection applies and trigger a validity. |
| 309 | */ |
| 310 | if (rc) |
| 311 | prefix_unmapped(vsie_page); |
| 312 | if (rc > 0 || rc == -EFAULT) |
| 313 | rc = set_validity_icpt(scb_s, 0x0037U); |
| 314 | return rc; |
| 315 | } |
| 316 | |
| 317 | /* |
| 318 | * Pin the guest page given by gpa and set hpa to the pinned host address. |
| 319 | * Will always be pinned writable. |
| 320 | * |
| 321 | * Returns: - 0 on success |
| 322 | * - -EINVAL if the gpa is not valid guest storage |
| 323 | * - -ENOMEM if out of memory |
| 324 | */ |
| 325 | static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa) |
| 326 | { |
| 327 | struct page *page; |
| 328 | hva_t hva; |
| 329 | int rc; |
| 330 | |
| 331 | hva = gfn_to_hva(kvm, gpa_to_gfn(gpa)); |
| 332 | if (kvm_is_error_hva(hva)) |
| 333 | return -EINVAL; |
| 334 | rc = get_user_pages_fast(hva, 1, 1, &page); |
| 335 | if (rc < 0) |
| 336 | return rc; |
| 337 | else if (rc != 1) |
| 338 | return -ENOMEM; |
| 339 | *hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK); |
| 340 | return 0; |
| 341 | } |
| 342 | |
| 343 | /* Unpins a page previously pinned via pin_guest_page, marking it as dirty. */ |
| 344 | static void unpin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t hpa) |
| 345 | { |
| 346 | struct page *page; |
| 347 | |
| 348 | page = virt_to_page(hpa); |
| 349 | set_page_dirty_lock(page); |
| 350 | put_page(page); |
| 351 | /* mark the page always as dirty for migration */ |
| 352 | mark_page_dirty(kvm, gpa_to_gfn(gpa)); |
| 353 | } |
| 354 | |
| 355 | /* unpin all blocks previously pinned by pin_blocks(), marking them dirty */ |
| 356 | static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 357 | { |
| 358 | struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; |
| 359 | struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; |
| 360 | hpa_t hpa; |
| 361 | gpa_t gpa; |
| 362 | |
| 363 | hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol; |
| 364 | if (hpa) { |
| 365 | gpa = scb_o->scaol & ~0xfUL; |
| 366 | unpin_guest_page(vcpu->kvm, gpa, hpa); |
| 367 | scb_s->scaol = 0; |
| 368 | scb_s->scaoh = 0; |
| 369 | } |
| 370 | } |
| 371 | |
| 372 | /* |
| 373 | * Instead of shadowing some blocks, we can simply forward them because the |
| 374 | * addresses in the scb are 64 bit long. |
| 375 | * |
| 376 | * This works as long as the data lies in one page. If blocks ever exceed one |
| 377 | * page, we have to fall back to shadowing. |
| 378 | * |
| 379 | * As we reuse the sca, the vcpu pointers contained in it are invalid. We must |
| 380 | * therefore not enable any facilities that access these pointers (e.g. SIGPIF). |
| 381 | * |
| 382 | * Returns: - 0 if all blocks were pinned. |
| 383 | * - > 0 if control has to be given to guest 2 |
| 384 | * - -ENOMEM if out of memory |
| 385 | */ |
| 386 | static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 387 | { |
| 388 | struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; |
| 389 | struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; |
| 390 | hpa_t hpa; |
| 391 | gpa_t gpa; |
| 392 | int rc = 0; |
| 393 | |
| 394 | gpa = scb_o->scaol & ~0xfUL; |
| 395 | if (gpa) { |
| 396 | if (!(gpa & ~0x1fffUL)) |
| 397 | rc = set_validity_icpt(scb_s, 0x0038U); |
| 398 | else if ((gpa & ~0x1fffUL) == kvm_s390_get_prefix(vcpu)) |
| 399 | rc = set_validity_icpt(scb_s, 0x0011U); |
| 400 | else if ((gpa & PAGE_MASK) != |
| 401 | ((gpa + sizeof(struct bsca_block) - 1) & PAGE_MASK)) |
| 402 | rc = set_validity_icpt(scb_s, 0x003bU); |
| 403 | if (!rc) { |
| 404 | rc = pin_guest_page(vcpu->kvm, gpa, &hpa); |
| 405 | if (rc == -EINVAL) |
| 406 | rc = set_validity_icpt(scb_s, 0x0034U); |
| 407 | } |
| 408 | if (rc) |
| 409 | goto unpin; |
| 410 | scb_s->scaoh = (u32)((u64)hpa >> 32); |
| 411 | scb_s->scaol = (u32)(u64)hpa; |
| 412 | } |
| 413 | return 0; |
| 414 | unpin: |
| 415 | unpin_blocks(vcpu, vsie_page); |
| 416 | return rc; |
| 417 | } |
| 418 | |
| 419 | /* unpin the scb provided by guest 2, marking it as dirty */ |
| 420 | static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, |
| 421 | gpa_t gpa) |
| 422 | { |
| 423 | hpa_t hpa = (hpa_t) vsie_page->scb_o; |
| 424 | |
| 425 | if (hpa) |
| 426 | unpin_guest_page(vcpu->kvm, gpa, hpa); |
| 427 | vsie_page->scb_o = NULL; |
| 428 | } |
| 429 | |
| 430 | /* |
| 431 | * Pin the scb at gpa provided by guest 2 at vsie_page->scb_o. |
| 432 | * |
| 433 | * Returns: - 0 if the scb was pinned. |
| 434 | * - > 0 if control has to be given to guest 2 |
| 435 | * - -ENOMEM if out of memory |
| 436 | */ |
| 437 | static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, |
| 438 | gpa_t gpa) |
| 439 | { |
| 440 | hpa_t hpa; |
| 441 | int rc; |
| 442 | |
| 443 | rc = pin_guest_page(vcpu->kvm, gpa, &hpa); |
| 444 | if (rc == -EINVAL) { |
| 445 | rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); |
| 446 | if (!rc) |
| 447 | rc = 1; |
| 448 | } |
| 449 | if (!rc) |
| 450 | vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa; |
| 451 | return rc; |
| 452 | } |
| 453 | |
| 454 | /* |
| 455 | * Inject a fault into guest 2. |
| 456 | * |
| 457 | * Returns: - > 0 if control has to be given to guest 2 |
| 458 | * < 0 if an error occurred during injection. |
| 459 | */ |
| 460 | static int inject_fault(struct kvm_vcpu *vcpu, __u16 code, __u64 vaddr, |
| 461 | bool write_flag) |
| 462 | { |
| 463 | struct kvm_s390_pgm_info pgm = { |
| 464 | .code = code, |
| 465 | .trans_exc_code = |
| 466 | /* 0-51: virtual address */ |
| 467 | (vaddr & 0xfffffffffffff000UL) | |
| 468 | /* 52-53: store / fetch */ |
| 469 | (((unsigned int) !write_flag) + 1) << 10, |
| 470 | /* 62-63: asce id (alway primary == 0) */ |
| 471 | .exc_access_id = 0, /* always primary */ |
| 472 | .op_access_id = 0, /* not MVPG */ |
| 473 | }; |
| 474 | int rc; |
| 475 | |
| 476 | if (code == PGM_PROTECTION) |
| 477 | pgm.trans_exc_code |= 0x4UL; |
| 478 | |
| 479 | rc = kvm_s390_inject_prog_irq(vcpu, &pgm); |
| 480 | return rc ? rc : 1; |
| 481 | } |
| 482 | |
| 483 | /* |
| 484 | * Handle a fault during vsie execution on a gmap shadow. |
| 485 | * |
| 486 | * Returns: - 0 if the fault was resolved |
| 487 | * - > 0 if control has to be given to guest 2 |
| 488 | * - < 0 if an error occurred |
| 489 | */ |
| 490 | static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 491 | { |
| 492 | int rc; |
| 493 | |
| 494 | if (current->thread.gmap_int_code == PGM_PROTECTION) |
| 495 | /* we can directly forward all protection exceptions */ |
| 496 | return inject_fault(vcpu, PGM_PROTECTION, |
| 497 | current->thread.gmap_addr, 1); |
| 498 | |
| 499 | rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, |
| 500 | current->thread.gmap_addr); |
| 501 | if (rc > 0) { |
| 502 | rc = inject_fault(vcpu, rc, |
| 503 | current->thread.gmap_addr, |
| 504 | current->thread.gmap_write_flag); |
| 505 | } |
| 506 | return rc; |
| 507 | } |
| 508 | |
| 509 | static inline void clear_vsie_icpt(struct vsie_page *vsie_page) |
| 510 | { |
| 511 | vsie_page->scb_s.icptcode = 0; |
| 512 | } |
| 513 | |
| 514 | /* |
| 515 | * Run the vsie on a shadow scb and a shadow gmap, without any further |
| 516 | * sanity checks, handling SIE faults. |
| 517 | * |
| 518 | * Returns: - 0 everything went fine |
| 519 | * - > 0 if control has to be given to guest 2 |
| 520 | * - < 0 if an error occurred |
| 521 | */ |
| 522 | static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 523 | { |
| 524 | struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; |
| 525 | struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; |
| 526 | int rc; |
| 527 | |
| 528 | if (need_resched()) |
| 529 | schedule(); |
| 530 | if (test_cpu_flag(CIF_MCCK_PENDING)) |
| 531 | s390_handle_mcck(); |
| 532 | |
| 533 | srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); |
| 534 | local_irq_disable(); |
| 535 | kvm_guest_enter(); |
| 536 | local_irq_enable(); |
| 537 | |
| 538 | rc = sie64a(scb_s, vcpu->run->s.regs.gprs); |
| 539 | |
| 540 | local_irq_disable(); |
| 541 | kvm_guest_exit(); |
| 542 | local_irq_enable(); |
| 543 | vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); |
| 544 | |
| 545 | if (rc > 0) |
| 546 | rc = 0; /* we could still have an icpt */ |
| 547 | else if (rc == -EFAULT) |
| 548 | return handle_fault(vcpu, vsie_page); |
| 549 | |
| 550 | switch (scb_s->icptcode) { |
| 551 | case ICPT_STOP: |
| 552 | /* stop not requested by g2 - must have been a kick */ |
| 553 | if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT)) |
| 554 | clear_vsie_icpt(vsie_page); |
| 555 | break; |
| 556 | case ICPT_VALIDITY: |
| 557 | if ((scb_s->ipa & 0xf000) != 0xf000) |
| 558 | scb_s->ipa += 0x1000; |
| 559 | break; |
| 560 | } |
| 561 | return rc; |
| 562 | } |
| 563 | |
| 564 | static void release_gmap_shadow(struct vsie_page *vsie_page) |
| 565 | { |
| 566 | if (vsie_page->gmap) |
| 567 | gmap_put(vsie_page->gmap); |
| 568 | WRITE_ONCE(vsie_page->gmap, NULL); |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 569 | prefix_unmapped(vsie_page); |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 570 | } |
| 571 | |
| 572 | static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, |
| 573 | struct vsie_page *vsie_page) |
| 574 | { |
| 575 | unsigned long asce; |
| 576 | union ctlreg0 cr0; |
| 577 | struct gmap *gmap; |
| 578 | int edat; |
| 579 | |
| 580 | asce = vcpu->arch.sie_block->gcr[1]; |
| 581 | cr0.val = vcpu->arch.sie_block->gcr[0]; |
| 582 | edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8); |
| 583 | edat += edat && test_kvm_facility(vcpu->kvm, 78); |
| 584 | |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 585 | /* |
| 586 | * ASCE or EDAT could have changed since last icpt, or the gmap |
| 587 | * we're holding has been unshadowed. If the gmap is still valid, |
| 588 | * we can safely reuse it. |
| 589 | */ |
| 590 | if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat)) |
| 591 | return 0; |
| 592 | |
| 593 | /* release the old shadow - if any, and mark the prefix as unmapped */ |
| 594 | release_gmap_shadow(vsie_page); |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 595 | gmap = gmap_shadow(vcpu->arch.gmap, asce, edat); |
| 596 | if (IS_ERR(gmap)) |
| 597 | return PTR_ERR(gmap); |
| 598 | gmap->private = vcpu->kvm; |
| 599 | WRITE_ONCE(vsie_page->gmap, gmap); |
| 600 | return 0; |
| 601 | } |
| 602 | |
| 603 | /* |
| 604 | * Run the vsie on a shadowed scb, managing the gmap shadow, handling |
| 605 | * prefix pages and faults. |
| 606 | * |
| 607 | * Returns: - 0 if no errors occurred |
| 608 | * - > 0 if control has to be given to guest 2 |
| 609 | * - -ENOMEM if out of memory |
| 610 | */ |
| 611 | static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) |
| 612 | { |
| 613 | struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; |
| 614 | int rc = 0; |
| 615 | |
| 616 | while (1) { |
| 617 | rc = acquire_gmap_shadow(vcpu, vsie_page); |
| 618 | if (!rc) |
| 619 | rc = map_prefix(vcpu, vsie_page); |
| 620 | if (!rc) { |
| 621 | gmap_enable(vsie_page->gmap); |
| 622 | update_intervention_requests(vsie_page); |
| 623 | rc = do_vsie_run(vcpu, vsie_page); |
| 624 | gmap_enable(vcpu->arch.gmap); |
| 625 | } |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 626 | |
| 627 | if (rc == -EAGAIN) |
| 628 | rc = 0; |
| 629 | if (rc || scb_s->icptcode || signal_pending(current) || |
| 630 | kvm_s390_vcpu_has_irq(vcpu, 0)) |
| 631 | break; |
| 632 | }; |
| 633 | |
| 634 | if (rc == -EFAULT) { |
| 635 | /* |
| 636 | * Addressing exceptions are always presentes as intercepts. |
| 637 | * As addressing exceptions are suppressing and our guest 3 PSW |
| 638 | * points at the responsible instruction, we have to |
| 639 | * forward the PSW and set the ilc. If we can't read guest 3 |
| 640 | * instruction, we can use an arbitrary ilc. Let's always use |
| 641 | * ilen = 4 for now, so we can avoid reading in guest 3 virtual |
| 642 | * memory. (we could also fake the shadow so the hardware |
| 643 | * handles it). |
| 644 | */ |
| 645 | scb_s->icptcode = ICPT_PROGI; |
| 646 | scb_s->iprcc = PGM_ADDRESSING; |
| 647 | scb_s->pgmilc = 4; |
| 648 | scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4); |
| 649 | } |
| 650 | return rc; |
| 651 | } |
| 652 | |
| 653 | /* |
| 654 | * Get or create a vsie page for a scb address. |
| 655 | * |
| 656 | * Returns: - address of a vsie page (cached or new one) |
| 657 | * - NULL if the same scb address is already used by another VCPU |
| 658 | * - ERR_PTR(-ENOMEM) if out of memory |
| 659 | */ |
| 660 | static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr) |
| 661 | { |
| 662 | struct vsie_page *vsie_page; |
| 663 | struct page *page; |
| 664 | int nr_vcpus; |
| 665 | |
| 666 | rcu_read_lock(); |
| 667 | page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9); |
| 668 | rcu_read_unlock(); |
| 669 | if (page) { |
| 670 | if (page_ref_inc_return(page) == 2) |
| 671 | return page_to_virt(page); |
| 672 | page_ref_dec(page); |
| 673 | } |
| 674 | |
| 675 | /* |
| 676 | * We want at least #online_vcpus shadows, so every VCPU can execute |
| 677 | * the VSIE in parallel. |
| 678 | */ |
| 679 | nr_vcpus = atomic_read(&kvm->online_vcpus); |
| 680 | |
| 681 | mutex_lock(&kvm->arch.vsie.mutex); |
| 682 | if (kvm->arch.vsie.page_count < nr_vcpus) { |
| 683 | page = alloc_page(GFP_KERNEL | __GFP_ZERO); |
| 684 | if (!page) { |
| 685 | mutex_unlock(&kvm->arch.vsie.mutex); |
| 686 | return ERR_PTR(-ENOMEM); |
| 687 | } |
| 688 | page_ref_inc(page); |
| 689 | kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page; |
| 690 | kvm->arch.vsie.page_count++; |
| 691 | } else { |
| 692 | /* reuse an existing entry that belongs to nobody */ |
| 693 | while (true) { |
| 694 | page = kvm->arch.vsie.pages[kvm->arch.vsie.next]; |
| 695 | if (page_ref_inc_return(page) == 2) |
| 696 | break; |
| 697 | page_ref_dec(page); |
| 698 | kvm->arch.vsie.next++; |
| 699 | kvm->arch.vsie.next %= nr_vcpus; |
| 700 | } |
| 701 | radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9); |
| 702 | } |
| 703 | page->index = addr; |
| 704 | /* double use of the same address */ |
| 705 | if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) { |
| 706 | page_ref_dec(page); |
| 707 | mutex_unlock(&kvm->arch.vsie.mutex); |
| 708 | return NULL; |
| 709 | } |
| 710 | mutex_unlock(&kvm->arch.vsie.mutex); |
| 711 | |
| 712 | vsie_page = page_to_virt(page); |
| 713 | memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block)); |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 714 | release_gmap_shadow(vsie_page); |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 715 | vsie_page->scb_s.ihcpu = 0xffffU; |
| 716 | return vsie_page; |
| 717 | } |
| 718 | |
| 719 | /* put a vsie page acquired via get_vsie_page */ |
| 720 | static void put_vsie_page(struct kvm *kvm, struct vsie_page *vsie_page) |
| 721 | { |
| 722 | struct page *page = pfn_to_page(__pa(vsie_page) >> PAGE_SHIFT); |
| 723 | |
| 724 | page_ref_dec(page); |
| 725 | } |
| 726 | |
| 727 | int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu) |
| 728 | { |
| 729 | struct vsie_page *vsie_page; |
| 730 | unsigned long scb_addr; |
| 731 | int rc; |
| 732 | |
| 733 | vcpu->stat.instruction_sie++; |
| 734 | if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIEF2)) |
| 735 | return -EOPNOTSUPP; |
| 736 | if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) |
| 737 | return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); |
| 738 | |
| 739 | BUILD_BUG_ON(sizeof(struct vsie_page) != 4096); |
| 740 | scb_addr = kvm_s390_get_base_disp_s(vcpu, NULL); |
| 741 | |
| 742 | /* 512 byte alignment */ |
| 743 | if (unlikely(scb_addr & 0x1ffUL)) |
| 744 | return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); |
| 745 | |
| 746 | if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0)) |
| 747 | return 0; |
| 748 | |
| 749 | vsie_page = get_vsie_page(vcpu->kvm, scb_addr); |
| 750 | if (IS_ERR(vsie_page)) |
| 751 | return PTR_ERR(vsie_page); |
| 752 | else if (!vsie_page) |
| 753 | /* double use of sie control block - simply do nothing */ |
| 754 | return 0; |
| 755 | |
| 756 | rc = pin_scb(vcpu, vsie_page, scb_addr); |
| 757 | if (rc) |
| 758 | goto out_put; |
| 759 | rc = shadow_scb(vcpu, vsie_page); |
| 760 | if (rc) |
| 761 | goto out_unpin_scb; |
| 762 | rc = pin_blocks(vcpu, vsie_page); |
| 763 | if (rc) |
| 764 | goto out_unshadow; |
| 765 | rc = vsie_run(vcpu, vsie_page); |
| 766 | unpin_blocks(vcpu, vsie_page); |
| 767 | out_unshadow: |
| 768 | unshadow_scb(vcpu, vsie_page); |
| 769 | out_unpin_scb: |
| 770 | unpin_scb(vcpu, vsie_page, scb_addr); |
| 771 | out_put: |
| 772 | put_vsie_page(vcpu->kvm, vsie_page); |
| 773 | |
| 774 | return rc < 0 ? rc : 0; |
| 775 | } |
| 776 | |
| 777 | /* Init the vsie data structures. To be called when a vm is initialized. */ |
| 778 | void kvm_s390_vsie_init(struct kvm *kvm) |
| 779 | { |
| 780 | mutex_init(&kvm->arch.vsie.mutex); |
| 781 | INIT_RADIX_TREE(&kvm->arch.vsie.addr_to_page, GFP_KERNEL); |
| 782 | } |
| 783 | |
| 784 | /* Destroy the vsie data structures. To be called when a vm is destroyed. */ |
| 785 | void kvm_s390_vsie_destroy(struct kvm *kvm) |
| 786 | { |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 787 | struct vsie_page *vsie_page; |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 788 | struct page *page; |
| 789 | int i; |
| 790 | |
| 791 | mutex_lock(&kvm->arch.vsie.mutex); |
| 792 | for (i = 0; i < kvm->arch.vsie.page_count; i++) { |
| 793 | page = kvm->arch.vsie.pages[i]; |
| 794 | kvm->arch.vsie.pages[i] = NULL; |
David Hildenbrand | 06d68a6 | 2016-04-22 13:50:09 +0200 | [diff] [blame] | 795 | vsie_page = page_to_virt(page); |
| 796 | release_gmap_shadow(vsie_page); |
David Hildenbrand | a3508fb | 2015-07-08 13:19:48 +0200 | [diff] [blame] | 797 | /* free the radix tree entry */ |
| 798 | radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9); |
| 799 | __free_page(page); |
| 800 | } |
| 801 | kvm->arch.vsie.page_count = 0; |
| 802 | mutex_unlock(&kvm->arch.vsie.mutex); |
| 803 | } |