// SPDX-License-Identifier: GPL-2.0 /* * guest access functions * * Copyright IBM Corp. 2014 * */ #include #include #include #include #include #include #include #include #include #include "kvm-s390.h" #include "gaccess.h" /* * vaddress union in order to easily decode a virtual address into its * region first index, region second index etc. parts. */ union vaddress { unsigned long addr; struct { unsigned long rfx : 11; unsigned long rsx : 11; unsigned long rtx : 11; unsigned long sx : 11; unsigned long px : 8; unsigned long bx : 12; }; struct { unsigned long rfx01 : 2; unsigned long : 9; unsigned long rsx01 : 2; unsigned long : 9; unsigned long rtx01 : 2; unsigned long : 9; unsigned long sx01 : 2; unsigned long : 29; }; }; /* * raddress union which will contain the result (real or absolute address) * after a page table walk. The rfaa, sfaa and pfra members are used to * simply assign them the value of a region, segment or page table entry. */ union raddress { unsigned long addr; unsigned long rfaa : 33; /* Region-Frame Absolute Address */ unsigned long sfaa : 44; /* Segment-Frame Absolute Address */ unsigned long pfra : 52; /* Page-Frame Real Address */ }; union alet { u32 val; struct { u32 reserved : 7; u32 p : 1; u32 alesn : 8; u32 alen : 16; }; }; union ald { u32 val; struct { u32 : 1; u32 alo : 24; u32 all : 7; }; }; struct ale { unsigned long i : 1; /* ALEN-Invalid Bit */ unsigned long : 5; unsigned long fo : 1; /* Fetch-Only Bit */ unsigned long p : 1; /* Private Bit */ unsigned long alesn : 8; /* Access-List-Entry Sequence Number */ unsigned long aleax : 16; /* Access-List-Entry Authorization Index */ unsigned long : 32; unsigned long : 1; unsigned long asteo : 25; /* ASN-Second-Table-Entry Origin */ unsigned long : 6; unsigned long astesn : 32; /* ASTE Sequence Number */ }; struct aste { unsigned long i : 1; /* ASX-Invalid Bit */ unsigned long ato : 29; /* Authority-Table Origin */ unsigned long : 1; unsigned long b : 1; /* Base-Space Bit */ unsigned long ax : 16; /* Authorization Index */ unsigned long atl : 12; /* Authority-Table Length */ unsigned long : 2; unsigned long ca : 1; /* Controlled-ASN Bit */ unsigned long ra : 1; /* Reusable-ASN Bit */ unsigned long asce : 64; /* Address-Space-Control Element */ unsigned long ald : 32; unsigned long astesn : 32; /* .. more fields there */ }; int ipte_lock_held(struct kvm *kvm) { if (sclp.has_siif) { int rc; read_lock(&kvm->arch.sca_lock); rc = kvm_s390_get_ipte_control(kvm)->kh != 0; read_unlock(&kvm->arch.sca_lock); return rc; } return kvm->arch.ipte_lock_count != 0; } static void ipte_lock_simple(struct kvm *kvm) { union ipte_control old, new, *ic; mutex_lock(&kvm->arch.ipte_mutex); kvm->arch.ipte_lock_count++; if (kvm->arch.ipte_lock_count > 1) goto out; retry: read_lock(&kvm->arch.sca_lock); ic = kvm_s390_get_ipte_control(kvm); old = READ_ONCE(*ic); do { if (old.k) { read_unlock(&kvm->arch.sca_lock); cond_resched(); goto retry; } new = old; new.k = 1; } while (!try_cmpxchg(&ic->val, &old.val, new.val)); read_unlock(&kvm->arch.sca_lock); out: mutex_unlock(&kvm->arch.ipte_mutex); } static void ipte_unlock_simple(struct kvm *kvm) { union ipte_control old, new, *ic; mutex_lock(&kvm->arch.ipte_mutex); kvm->arch.ipte_lock_count--; if (kvm->arch.ipte_lock_count) goto out; read_lock(&kvm->arch.sca_lock); ic = kvm_s390_get_ipte_control(kvm); old = READ_ONCE(*ic); do { new = old; new.k = 0; } while (!try_cmpxchg(&ic->val, &old.val, new.val)); read_unlock(&kvm->arch.sca_lock); wake_up(&kvm->arch.ipte_wq); out: mutex_unlock(&kvm->arch.ipte_mutex); } static void ipte_lock_siif(struct kvm *kvm) { union ipte_control old, new, *ic; retry: read_lock(&kvm->arch.sca_lock); ic = kvm_s390_get_ipte_control(kvm); old = READ_ONCE(*ic); do { if (old.kg) { read_unlock(&kvm->arch.sca_lock); cond_resched(); goto retry; } new = old; new.k = 1; new.kh++; } while (!try_cmpxchg(&ic->val, &old.val, new.val)); read_unlock(&kvm->arch.sca_lock); } static void ipte_unlock_siif(struct kvm *kvm) { union ipte_control old, new, *ic; read_lock(&kvm->arch.sca_lock); ic = kvm_s390_get_ipte_control(kvm); old = READ_ONCE(*ic); do { new = old; new.kh--; if (!new.kh) new.k = 0; } while (!try_cmpxchg(&ic->val, &old.val, new.val)); read_unlock(&kvm->arch.sca_lock); if (!new.kh) wake_up(&kvm->arch.ipte_wq); } void ipte_lock(struct kvm *kvm) { if (sclp.has_siif) ipte_lock_siif(kvm); else ipte_lock_simple(kvm); } void ipte_unlock(struct kvm *kvm) { if (sclp.has_siif) ipte_unlock_siif(kvm); else ipte_unlock_simple(kvm); } static int ar_translation(struct kvm_vcpu *vcpu, union asce *asce, u8 ar, enum gacc_mode mode) { union alet alet; struct ale ale; struct aste aste; unsigned long ald_addr, authority_table_addr; union ald ald; int eax, rc; u8 authority_table; if (ar >= NUM_ACRS) return -EINVAL; if (vcpu->arch.acrs_loaded) save_access_regs(vcpu->run->s.regs.acrs); alet.val = vcpu->run->s.regs.acrs[ar]; if (ar == 0 || alet.val == 0) { asce->val = vcpu->arch.sie_block->gcr[1]; return 0; } else if (alet.val == 1) { asce->val = vcpu->arch.sie_block->gcr[7]; return 0; } if (alet.reserved) return PGM_ALET_SPECIFICATION; if (alet.p) ald_addr = vcpu->arch.sie_block->gcr[5]; else ald_addr = vcpu->arch.sie_block->gcr[2]; ald_addr &= 0x7fffffc0; rc = read_guest_real(vcpu, ald_addr + 16, &ald.val, sizeof(union ald)); if (rc) return rc; if (alet.alen / 8 > ald.all) return PGM_ALEN_TRANSLATION; if (0x7fffffff - ald.alo * 128 < alet.alen * 16) return PGM_ADDRESSING; rc = read_guest_real(vcpu, ald.alo * 128 + alet.alen * 16, &ale, sizeof(struct ale)); if (rc) return rc; if (ale.i == 1) return PGM_ALEN_TRANSLATION; if (ale.alesn != alet.alesn) return PGM_ALE_SEQUENCE; rc = read_guest_real(vcpu, ale.asteo * 64, &aste, sizeof(struct aste)); if (rc) return rc; if (aste.i) return PGM_ASTE_VALIDITY; if (aste.astesn != ale.astesn) return PGM_ASTE_SEQUENCE; if (ale.p == 1) { eax = (vcpu->arch.sie_block->gcr[8] >> 16) & 0xffff; if (ale.aleax != eax) { if (eax / 16 > aste.atl) return PGM_EXTENDED_AUTHORITY; authority_table_addr = aste.ato * 4 + eax / 4; rc = read_guest_real(vcpu, authority_table_addr, &authority_table, sizeof(u8)); if (rc) return rc; if ((authority_table & (0x40 >> ((eax & 3) * 2))) == 0) return PGM_EXTENDED_AUTHORITY; } } if (ale.fo == 1 && mode == GACC_STORE) return PGM_PROTECTION; asce->val = aste.asce; return 0; } enum prot_type { PROT_TYPE_LA = 0, PROT_TYPE_KEYC = 1, PROT_TYPE_ALC = 2, PROT_TYPE_DAT = 3, PROT_TYPE_IEP = 4, /* Dummy value for passing an initialized value when code != PGM_PROTECTION */ PROT_NONE, }; static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar, enum gacc_mode mode, enum prot_type prot, bool terminate) { struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm; union teid *teid; memset(pgm, 0, sizeof(*pgm)); pgm->code = code; teid = (union teid *)&pgm->trans_exc_code; switch (code) { case PGM_PROTECTION: switch (prot) { case PROT_NONE: /* We should never get here, acts like termination */ WARN_ON_ONCE(1); break; case PROT_TYPE_IEP: teid->b61 = 1; fallthrough; case PROT_TYPE_LA: teid->b56 = 1; break; case PROT_TYPE_KEYC: teid->b60 = 1; break; case PROT_TYPE_ALC: teid->b60 = 1; fallthrough; case PROT_TYPE_DAT: teid->b61 = 1; break; } if (terminate) { teid->b56 = 0; teid->b60 = 0; teid->b61 = 0; } fallthrough; case PGM_ASCE_TYPE: case PGM_PAGE_TRANSLATION: case PGM_REGION_FIRST_TRANS: case PGM_REGION_SECOND_TRANS: case PGM_REGION_THIRD_TRANS: case PGM_SEGMENT_TRANSLATION: /* * op_access_id only applies to MOVE_PAGE -> set bit 61 * exc_access_id has to be set to 0 for some instructions. Both * cases have to be handled by the caller. */ teid->addr = gva >> PAGE_SHIFT; teid->fsi = mode == GACC_STORE ? TEID_FSI_STORE : TEID_FSI_FETCH; teid->as = psw_bits(vcpu->arch.sie_block->gpsw).as; fallthrough; case PGM_ALEN_TRANSLATION: case PGM_ALE_SEQUENCE: case PGM_ASTE_VALIDITY: case PGM_ASTE_SEQUENCE: case PGM_EXTENDED_AUTHORITY: /* * We can always store exc_access_id, as it is * undefined for non-ar cases. It is undefined for * most DAT protection exceptions. */ pgm->exc_access_id = ar; break; } return code; } static int trans_exc(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar, enum gacc_mode mode, enum prot_type prot) { return trans_exc_ending(vcpu, code, gva, ar, mode, prot, false); } static int get_vcpu_asce(struct kvm_vcpu *vcpu, union asce *asce, unsigned long ga, u8 ar, enum gacc_mode mode) { int rc; struct psw_bits psw = psw_bits(vcpu->arch.sie_block->gpsw); if (!psw.dat) { asce->val = 0; asce->r = 1; return 0; } if ((mode == GACC_IFETCH) && (psw.as != PSW_BITS_AS_HOME)) psw.as = PSW_BITS_AS_PRIMARY; switch (psw.as) { case PSW_BITS_AS_PRIMARY: asce->val = vcpu->arch.sie_block->gcr[1]; return 0; case PSW_BITS_AS_SECONDARY: asce->val = vcpu->arch.sie_block->gcr[7]; return 0; case PSW_BITS_AS_HOME: asce->val = vcpu->arch.sie_block->gcr[13]; return 0; case PSW_BITS_AS_ACCREG: rc = ar_translation(vcpu, asce, ar, mode); if (rc > 0) return trans_exc(vcpu, rc, ga, ar, mode, PROT_TYPE_ALC); return rc; } return 0; } static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val) { return kvm_read_guest(kvm, gpa, val, sizeof(*val)); } /** * guest_translate - translate a guest virtual into a guest absolute address * @vcpu: virtual cpu * @gva: guest virtual address * @gpa: points to where guest physical (absolute) address should be stored * @asce: effective asce * @mode: indicates the access mode to be used * @prot: returns the type for protection exceptions * * Translate a guest virtual address into a guest absolute address by means * of dynamic address translation as specified by the architecture. * If the resulting absolute address is not available in the configuration * an addressing exception is indicated and @gpa will not be changed. * * Returns: - zero on success; @gpa contains the resulting absolute address * - a negative value if guest access failed due to e.g. broken * guest mapping * - a positive value if an access exception happened. In this case * the returned value is the program interruption code as defined * by the architecture */ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva, unsigned long *gpa, const union asce asce, enum gacc_mode mode, enum prot_type *prot) { union vaddress vaddr = {.addr = gva}; union raddress raddr = {.addr = gva}; union page_table_entry pte; int dat_protection = 0; int iep_protection = 0; union ctlreg0 ctlreg0; unsigned long ptr; int edat1, edat2, iep; ctlreg0.val = vcpu->arch.sie_block->gcr[0]; edat1 = ctlreg0.edat && test_kvm_facility(vcpu->kvm, 8); edat2 = edat1 && test_kvm_facility(vcpu->kvm, 78); iep = ctlreg0.iep && test_kvm_facility(vcpu->kvm, 130); if (asce.r) goto real_address; ptr = asce.rsto * PAGE_SIZE; switch (asce.dt) { case ASCE_TYPE_REGION1: if (vaddr.rfx01 > asce.tl) return PGM_REGION_FIRST_TRANS; ptr += vaddr.rfx * 8; break; case ASCE_TYPE_REGION2: if (vaddr.rfx) return PGM_ASCE_TYPE; if (vaddr.rsx01 > asce.tl) return PGM_REGION_SECOND_TRANS; ptr += vaddr.rsx * 8; break; case ASCE_TYPE_REGION3: if (vaddr.rfx || vaddr.rsx) return PGM_ASCE_TYPE; if (vaddr.rtx01 > asce.tl) return PGM_REGION_THIRD_TRANS; ptr += vaddr.rtx * 8; break; case ASCE_TYPE_SEGMENT: if (vaddr.rfx || vaddr.rsx || vaddr.rtx) return PGM_ASCE_TYPE; if (vaddr.sx01 > asce.tl) return PGM_SEGMENT_TRANSLATION; ptr += vaddr.sx * 8; break; } switch (asce.dt) { case ASCE_TYPE_REGION1: { union region1_table_entry rfte; if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) return PGM_ADDRESSING; if (deref_table(vcpu->kvm, ptr, &rfte.val)) return -EFAULT; if (rfte.i) return PGM_REGION_FIRST_TRANS; if (rfte.tt != TABLE_TYPE_REGION1) return PGM_TRANSLATION_SPEC; if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl) return PGM_REGION_SECOND_TRANS; if (edat1) dat_protection |= rfte.p; ptr = rfte.rto * PAGE_SIZE + vaddr.rsx * 8; } fallthrough; case ASCE_TYPE_REGION2: { union region2_table_entry rste; if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) return PGM_ADDRESSING; if (deref_table(vcpu->kvm, ptr, &rste.val)) return -EFAULT; if (rste.i) return PGM_REGION_SECOND_TRANS; if (rste.tt != TABLE_TYPE_REGION2) return PGM_TRANSLATION_SPEC; if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl) return PGM_REGION_THIRD_TRANS; if (edat1) dat_protection |= rste.p; ptr = rste.rto * PAGE_SIZE + vaddr.rtx * 8; } fallthrough; case ASCE_TYPE_REGION3: { union region3_table_entry rtte; if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) return PGM_ADDRESSING; if (deref_table(vcpu->kvm, ptr, &rtte.val)) return -EFAULT; if (rtte.i) return PGM_REGION_THIRD_TRANS; if (rtte.tt != TABLE_TYPE_REGION3) return PGM_TRANSLATION_SPEC; if (rtte.cr && asce.p && edat2) return PGM_TRANSLATION_SPEC; if (rtte.fc && edat2) { dat_protection |= rtte.fc1.p; iep_protection = rtte.fc1.iep; raddr.rfaa = rtte.fc1.rfaa; goto absolute_address; } if (vaddr.sx01 < rtte.fc0.tf) return PGM_SEGMENT_TRANSLATION; if (vaddr.sx01 > rtte.fc0.tl) return PGM_SEGMENT_TRANSLATION; if (edat1) dat_protection |= rtte.fc0.p; ptr = rtte.fc0.sto * PAGE_SIZE + vaddr.sx * 8; } fallthrough; case ASCE_TYPE_SEGMENT: { union segment_table_entry ste; if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) return PGM_ADDRESSING; if (deref_table(vcpu->kvm, ptr, &ste.val)) return -EFAULT; if (ste.i) return PGM_SEGMENT_TRANSLATION; if (ste.tt != TABLE_TYPE_SEGMENT) return PGM_TRANSLATION_SPEC; if (ste.cs && asce.p) return PGM_TRANSLATION_SPEC; if (ste.fc && edat1) { dat_protection |= ste.fc1.p; iep_protection = ste.fc1.iep; raddr.sfaa = ste.fc1.sfaa; goto absolute_address; } dat_protection |= ste.fc0.p; ptr = ste.fc0.pto * (PAGE_SIZE / 2) + vaddr.px * 8; } } if (!kvm_is_gpa_in_memslot(vcpu->kvm, ptr)) return PGM_ADDRESSING; if (deref_table(vcpu->kvm, ptr, &pte.val)) return -EFAULT; if (pte.i) return PGM_PAGE_TRANSLATION; if (pte.z) return PGM_TRANSLATION_SPEC; dat_protection |= pte.p; iep_protection = pte.iep; raddr.pfra = pte.pfra; real_address: raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr); absolute_address: if (mode == GACC_STORE && dat_protection) { *prot = PROT_TYPE_DAT; return PGM_PROTECTION; } if (mode == GACC_IFETCH && iep_protection && iep) { *prot = PROT_TYPE_IEP; return PGM_PROTECTION; } if (!kvm_is_gpa_in_memslot(vcpu->kvm, raddr.addr)) return PGM_ADDRESSING; *gpa = raddr.addr; return 0; } static inline int is_low_address(unsigned long ga) { /* Check for address ranges 0..511 and 4096..4607 */ return (ga & ~0x11fful) == 0; } static int low_address_protection_enabled(struct kvm_vcpu *vcpu, const union asce asce) { union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]}; psw_t *psw = &vcpu->arch.sie_block->gpsw; if (!ctlreg0.lap) return 0; if (psw_bits(*psw).dat && asce.p) return 0; return 1; } static int vm_check_access_key(struct kvm *kvm, u8 access_key, enum gacc_mode mode, gpa_t gpa) { u8 storage_key, access_control; bool fetch_protected; unsigned long hva; int r; if (access_key == 0) return 0; hva = gfn_to_hva(kvm, gpa_to_gfn(gpa)); if (kvm_is_error_hva(hva)) return PGM_ADDRESSING; mmap_read_lock(current->mm); r = get_guest_storage_key(current->mm, hva, &storage_key); mmap_read_unlock(current->mm); if (r) return r; access_control = FIELD_GET(_PAGE_ACC_BITS, storage_key); if (access_control == access_key) return 0; fetch_protected = storage_key & _PAGE_FP_BIT; if ((mode == GACC_FETCH || mode == GACC_IFETCH) && !fetch_protected) return 0; return PGM_PROTECTION; } static bool fetch_prot_override_applicable(struct kvm_vcpu *vcpu, enum gacc_mode mode, union asce asce) { psw_t *psw = &vcpu->arch.sie_block->gpsw; unsigned long override; if (mode == GACC_FETCH || mode == GACC_IFETCH) { /* check if fetch protection override enabled */ override = vcpu->arch.sie_block->gcr[0]; override &= CR0_FETCH_PROTECTION_OVERRIDE; /* not applicable if subject to DAT && private space */ override = override && !(psw_bits(*psw).dat && asce.p); return override; } return false; } static bool fetch_prot_override_applies(unsigned long ga, unsigned int len) { return ga < 2048 && ga + len <= 2048; } static bool storage_prot_override_applicable(struct kvm_vcpu *vcpu) { /* check if storage protection override enabled */ return vcpu->arch.sie_block->gcr[0] & CR0_STORAGE_PROTECTION_OVERRIDE; } static bool storage_prot_override_applies(u8 access_control) { /* matches special storage protection override key (9) -> allow */ return access_control == PAGE_SPO_ACC; } static int vcpu_check_access_key(struct kvm_vcpu *vcpu, u8 access_key, enum gacc_mode mode, union asce asce, gpa_t gpa, unsigned long ga, unsigned int len) { u8 storage_key, access_control; unsigned long hva; int r; /* access key 0 matches any storage key -> allow */ if (access_key == 0) return 0; /* * caller needs to ensure that gfn is accessible, so we can * assume that this cannot fail */ hva = gfn_to_hva(vcpu->kvm, gpa_to_gfn(gpa)); mmap_read_lock(current->mm); r = get_guest_storage_key(current->mm, hva, &storage_key); mmap_read_unlock(current->mm); if (r) return r; access_control = FIELD_GET(_PAGE_ACC_BITS, storage_key); /* access key matches storage key -> allow */ if (access_control == access_key) return 0; if (mode == GACC_FETCH || mode == GACC_IFETCH) { /* it is a fetch and fetch protection is off -> allow */ if (!(storage_key & _PAGE_FP_BIT)) return 0; if (fetch_prot_override_applicable(vcpu, mode, asce) && fetch_prot_override_applies(ga, len)) return 0; } if (storage_prot_override_applicable(vcpu) && storage_prot_override_applies(access_control)) return 0; return PGM_PROTECTION; } /** * guest_range_to_gpas() - Calculate guest physical addresses of page fragments * covering a logical range * @vcpu: virtual cpu * @ga: guest address, start of range * @ar: access register * @gpas: output argument, may be NULL * @len: length of range in bytes * @asce: address-space-control element to use for translation * @mode: access mode * @access_key: access key to mach the range's storage keys against * * Translate a logical range to a series of guest absolute addresses, * such that the concatenation of page fragments starting at each gpa make up * the whole range. * The translation is performed as if done by the cpu for the given @asce, @ar, * @mode and state of the @vcpu. * If the translation causes an exception, its program interruption code is * returned and the &struct kvm_s390_pgm_info pgm member of @vcpu is modified * such that a subsequent call to kvm_s390_inject_prog_vcpu() will inject * a correct exception into the guest. * The resulting gpas are stored into @gpas, unless it is NULL. * * Note: All fragments except the first one start at the beginning of a page. * When deriving the boundaries of a fragment from a gpa, all but the last * fragment end at the end of the page. * * Return: * * 0 - success * * <0 - translation could not be performed, for example if guest * memory could not be accessed * * >0 - an access exception occurred. In this case the returned value * is the program interruption code and the contents of pgm may * be used to inject an exception into the guest. */ static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, unsigned long *gpas, unsigned long len, const union asce asce, enum gacc_mode mode, u8 access_key) { psw_t *psw = &vcpu->arch.sie_block->gpsw; unsigned int offset = offset_in_page(ga); unsigned int fragment_len; int lap_enabled, rc = 0; enum prot_type prot; unsigned long gpa; lap_enabled = low_address_protection_enabled(vcpu, asce); while (min(PAGE_SIZE - offset, len) > 0) { fragment_len = min(PAGE_SIZE - offset, len); ga = kvm_s390_logical_to_effective(vcpu, ga); if (mode == GACC_STORE && lap_enabled && is_low_address(ga)) return trans_exc(vcpu, PGM_PROTECTION, ga, ar, mode, PROT_TYPE_LA); if (psw_bits(*psw).dat) { rc = guest_translate(vcpu, ga, &gpa, asce, mode, &prot); if (rc < 0) return rc; } else { gpa = kvm_s390_real_to_abs(vcpu, ga); if (!kvm_is_gpa_in_memslot(vcpu->kvm, gpa)) { rc = PGM_ADDRESSING; prot = PROT_NONE; } } if (rc) return trans_exc(vcpu, rc, ga, ar, mode, prot); rc = vcpu_check_access_key(vcpu, access_key, mode, asce, gpa, ga, fragment_len); if (rc) return trans_exc(vcpu, rc, ga, ar, mode, PROT_TYPE_KEYC); if (gpas) *gpas++ = gpa; offset = 0; ga += fragment_len; len -= fragment_len; } return 0; } static int access_guest_page(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa, void *data, unsigned int len) { const unsigned int offset = offset_in_page(gpa); const gfn_t gfn = gpa_to_gfn(gpa); int rc; if (!gfn_to_memslot(kvm, gfn)) return PGM_ADDRESSING; if (mode == GACC_STORE) rc = kvm_write_guest_page(kvm, gfn, data, offset, len); else rc = kvm_read_guest_page(kvm, gfn, data, offset, len); return rc; } static int access_guest_page_with_key(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa, void *data, unsigned int len, u8 access_key) { struct kvm_memory_slot *slot; bool writable; gfn_t gfn; hva_t hva; int rc; gfn = gpa >> PAGE_SHIFT; slot = gfn_to_memslot(kvm, gfn); hva = gfn_to_hva_memslot_prot(slot, gfn, &writable); if (kvm_is_error_hva(hva)) return PGM_ADDRESSING; /* * Check if it's a ro memslot, even tho that can't occur (they're unsupported). * Don't try to actually handle that case. */ if (!writable && mode == GACC_STORE) return -EOPNOTSUPP; hva += offset_in_page(gpa); if (mode == GACC_STORE) rc = copy_to_user_key((void __user *)hva, data, len, access_key); else rc = copy_from_user_key(data, (void __user *)hva, len, access_key); if (rc) return PGM_PROTECTION; if (mode == GACC_STORE) mark_page_dirty_in_slot(kvm, slot, gfn); return 0; } int access_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len, enum gacc_mode mode, u8 access_key) { int offset = offset_in_page(gpa); int fragment_len; int rc; while (min(PAGE_SIZE - offset, len) > 0) { fragment_len = min(PAGE_SIZE - offset, len); rc = access_guest_page_with_key(kvm, mode, gpa, data, fragment_len, access_key); if (rc) return rc; offset = 0; len -= fragment_len; data += fragment_len; gpa += fragment_len; } return 0; } int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data, unsigned long len, enum gacc_mode mode, u8 access_key) { psw_t *psw = &vcpu->arch.sie_block->gpsw; unsigned long nr_pages, idx; unsigned long gpa_array[2]; unsigned int fragment_len; unsigned long *gpas; enum prot_type prot; int need_ipte_lock; union asce asce; bool try_storage_prot_override; bool try_fetch_prot_override; int rc; if (!len) return 0; ga = kvm_s390_logical_to_effective(vcpu, ga); rc = get_vcpu_asce(vcpu, &asce, ga, ar, mode); if (rc) return rc; nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1; gpas = gpa_array; if (nr_pages > ARRAY_SIZE(gpa_array)) gpas = vmalloc(array_size(nr_pages, sizeof(unsigned long))); if (!gpas) return -ENOMEM; try_fetch_prot_override = fetch_prot_override_applicable(vcpu, mode, asce); try_storage_prot_override = storage_prot_override_applicable(vcpu); need_ipte_lock = psw_bits(*psw).dat && !asce.r; if (need_ipte_lock) ipte_lock(vcpu->kvm); /* * Since we do the access further down ultimately via a move instruction * that does key checking and returns an error in case of a protection * violation, we don't need to do the check during address translation. * Skip it by passing access key 0, which matches any storage key, * obviating the need for any further checks. As a result the check is * handled entirely in hardware on access, we only need to take care to * forego key protection checking if fetch protection override applies or * retry with the special key 9 in case of storage protection override. */ rc = guest_range_to_gpas(vcpu, ga, ar, gpas, len, asce, mode, 0); if (rc) goto out_unlock; for (idx = 0; idx < nr_pages; idx++) { fragment_len = min(PAGE_SIZE - offset_in_page(gpas[idx]), len); if (try_fetch_prot_override && fetch_prot_override_applies(ga, fragment_len)) { rc = access_guest_page(vcpu->kvm, mode, gpas[idx], data, fragment_len); } else { rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx], data, fragment_len, access_key); } if (rc == PGM_PROTECTION && try_storage_prot_override) rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx], data, fragment_len, PAGE_SPO_ACC); if (rc) break; len -= fragment_len; data += fragment_len; ga = kvm_s390_logical_to_effective(vcpu, ga + fragment_len); } if (rc > 0) { bool terminate = (mode == GACC_STORE) && (idx > 0); if (rc == PGM_PROTECTION) prot = PROT_TYPE_KEYC; else prot = PROT_NONE; rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate); } out_unlock: if (need_ipte_lock) ipte_unlock(vcpu->kvm); if (nr_pages > ARRAY_SIZE(gpa_array)) vfree(gpas); return rc; } int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, unsigned long len, enum gacc_mode mode) { unsigned int fragment_len; unsigned long gpa; int rc = 0; while (len && !rc) { gpa = kvm_s390_real_to_abs(vcpu, gra); fragment_len = min(PAGE_SIZE - offset_in_page(gpa), len); rc = access_guest_page(vcpu->kvm, mode, gpa, data, fragment_len); len -= fragment_len; gra += fragment_len; data += fragment_len; } if (rc > 0) vcpu->arch.pgm.code = rc; return rc; } /** * cmpxchg_guest_abs_with_key() - Perform cmpxchg on guest absolute address. * @kvm: Virtual machine instance. * @gpa: Absolute guest address of the location to be changed. * @len: Operand length of the cmpxchg, required: 1 <= len <= 16. Providing a * non power of two will result in failure. * @old_addr: Pointer to old value. If the location at @gpa contains this value, * the exchange will succeed. After calling cmpxchg_guest_abs_with_key() * *@old_addr contains the value at @gpa before the attempt to * exchange the value. * @new: The value to place at @gpa. * @access_key: The access key to use for the guest access. * @success: output value indicating if an exchange occurred. * * Atomically exchange the value at @gpa by @new, if it contains *@old. * Honors storage keys. * * Return: * 0: successful exchange * * >0: a program interruption code indicating the reason cmpxchg could * not be attempted * * -EINVAL: address misaligned or len not power of two * * -EAGAIN: transient failure (len 1 or 2) * * -EOPNOTSUPP: read-only memslot (should never occur) */ int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len, __uint128_t *old_addr, __uint128_t new, u8 access_key, bool *success) { gfn_t gfn = gpa_to_gfn(gpa); struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); bool writable; hva_t hva; int ret; if (!IS_ALIGNED(gpa, len)) return -EINVAL; hva = gfn_to_hva_memslot_prot(slot, gfn, &writable); if (kvm_is_error_hva(hva)) return PGM_ADDRESSING; /* * Check if it's a read-only memslot, even though that cannot occur * since those are unsupported. * Don't try to actually handle that case. */ if (!writable) return -EOPNOTSUPP; hva += offset_in_page(gpa); /* * The cmpxchg_user_key macro depends on the type of "old", so we need * a case for each valid length and get some code duplication as long * as we don't introduce a new macro. */ switch (len) { case 1: { u8 old; ret = cmpxchg_user_key((u8 __user *)hva, &old, *old_addr, new, access_key); *success = !ret && old == *old_addr; *old_addr = old; break; } case 2: { u16 old; ret = cmpxchg_user_key((u16 __user *)hva, &old, *old_addr, new, access_key); *success = !ret && old == *old_addr; *old_addr = old; break; } case 4: { u32 old; ret = cmpxchg_user_key((u32 __user *)hva, &old, *old_addr, new, access_key); *success = !ret && old == *old_addr; *old_addr = old; break; } case 8: { u64 old; ret = cmpxchg_user_key((u64 __user *)hva, &old, *old_addr, new, access_key); *success = !ret && old == *old_addr; *old_addr = old; break; } case 16: { __uint128_t old; ret = cmpxchg_user_key((__uint128_t __user *)hva, &old, *old_addr, new, access_key); *success = !ret && old == *old_addr; *old_addr = old; break; } default: return -EINVAL; } if (*success) mark_page_dirty_in_slot(kvm, slot, gfn); /* * Assume that the fault is caused by protection, either key protection * or user page write protection. */ if (ret == -EFAULT) ret = PGM_PROTECTION; return ret; } /** * guest_translate_address_with_key - translate guest logical into guest absolute address * @vcpu: virtual cpu * @gva: Guest virtual address * @ar: Access register * @gpa: Guest physical address * @mode: Translation access mode * @access_key: access key to mach the storage key with * * Parameter semantics are the same as the ones from guest_translate. * The memory contents at the guest address are not changed. * * Note: The IPTE lock is not taken during this function, so the caller * has to take care of this. */ int guest_translate_address_with_key(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar, unsigned long *gpa, enum gacc_mode mode, u8 access_key) { union asce asce; int rc; gva = kvm_s390_logical_to_effective(vcpu, gva); rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode); if (rc) return rc; return guest_range_to_gpas(vcpu, gva, ar, gpa, 1, asce, mode, access_key); } /** * check_gva_range - test a range of guest virtual addresses for accessibility * @vcpu: virtual cpu * @gva: Guest virtual address * @ar: Access register * @length: Length of test range * @mode: Translation access mode * @access_key: access key to mach the storage keys with */ int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar, unsigned long length, enum gacc_mode mode, u8 access_key) { union asce asce; int rc = 0; rc = get_vcpu_asce(vcpu, &asce, gva, ar, mode); if (rc) return rc; ipte_lock(vcpu->kvm); rc = guest_range_to_gpas(vcpu, gva, ar, NULL, length, asce, mode, access_key); ipte_unlock(vcpu->kvm); return rc; } /** * check_gpa_range - test a range of guest physical addresses for accessibility * @kvm: virtual machine instance * @gpa: guest physical address * @length: length of test range * @mode: access mode to test, relevant for storage keys * @access_key: access key to mach the storage keys with */ int check_gpa_range(struct kvm *kvm, unsigned long gpa, unsigned long length, enum gacc_mode mode, u8 access_key) { unsigned int fragment_len; int rc = 0; while (length && !rc) { fragment_len = min(PAGE_SIZE - offset_in_page(gpa), length); rc = vm_check_access_key(kvm, access_key, mode, gpa); length -= fragment_len; gpa += fragment_len; } return rc; } /** * kvm_s390_check_low_addr_prot_real - check for low-address protection * @vcpu: virtual cpu * @gra: Guest real address * * Checks whether an address is subject to low-address protection and set * up vcpu->arch.pgm accordingly if necessary. * * Return: 0 if no protection exception, or PGM_PROTECTION if protected. */ int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra) { union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]}; if (!ctlreg0.lap || !is_low_address(gra)) return 0; return trans_exc(vcpu, PGM_PROTECTION, gra, 0, GACC_STORE, PROT_TYPE_LA); } /** * kvm_s390_shadow_tables - walk the guest page table and create shadow tables * @sg: pointer to the shadow guest address space structure * @saddr: faulting address in the shadow gmap * @pgt: pointer to the beginning of the page table for the given address if * successful (return value 0), or to the first invalid DAT entry in * case of exceptions (return value > 0) * @dat_protection: referenced memory is write protected * @fake: pgt references contiguous guest memory block, not a pgtable */ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, unsigned long *pgt, int *dat_protection, int *fake) { struct kvm *kvm; struct gmap *parent; union asce asce; union vaddress vaddr; unsigned long ptr; int rc; *fake = 0; *dat_protection = 0; kvm = sg->private; parent = sg->parent; vaddr.addr = saddr; asce.val = sg->orig_asce; ptr = asce.rsto * PAGE_SIZE; if (asce.r) { *fake = 1; ptr = 0; asce.dt = ASCE_TYPE_REGION1; } switch (asce.dt) { case ASCE_TYPE_REGION1: if (vaddr.rfx01 > asce.tl && !*fake) return PGM_REGION_FIRST_TRANS; break; case ASCE_TYPE_REGION2: if (vaddr.rfx) return PGM_ASCE_TYPE; if (vaddr.rsx01 > asce.tl) return PGM_REGION_SECOND_TRANS; break; case ASCE_TYPE_REGION3: if (vaddr.rfx || vaddr.rsx) return PGM_ASCE_TYPE; if (vaddr.rtx01 > asce.tl) return PGM_REGION_THIRD_TRANS; break; case ASCE_TYPE_SEGMENT: if (vaddr.rfx || vaddr.rsx || vaddr.rtx) return PGM_ASCE_TYPE; if (vaddr.sx01 > asce.tl) return PGM_SEGMENT_TRANSLATION; break; } switch (asce.dt) { case ASCE_TYPE_REGION1: { union region1_table_entry rfte; if (*fake) { ptr += vaddr.rfx * _REGION1_SIZE; rfte.val = ptr; goto shadow_r2t; } *pgt = ptr + vaddr.rfx * 8; rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val); if (rc) return rc; if (rfte.i) return PGM_REGION_FIRST_TRANS; if (rfte.tt != TABLE_TYPE_REGION1) return PGM_TRANSLATION_SPEC; if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl) return PGM_REGION_SECOND_TRANS; if (sg->edat_level >= 1) *dat_protection |= rfte.p; ptr = rfte.rto * PAGE_SIZE; shadow_r2t: rc = gmap_shadow_r2t(sg, saddr, rfte.val, *fake); if (rc) return rc; kvm->stat.gmap_shadow_r1_entry++; } fallthrough; case ASCE_TYPE_REGION2: { union region2_table_entry rste; if (*fake) { ptr += vaddr.rsx * _REGION2_SIZE; rste.val = ptr; goto shadow_r3t; } *pgt = ptr + vaddr.rsx * 8; rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val); if (rc) return rc; if (rste.i) return PGM_REGION_SECOND_TRANS; if (rste.tt != TABLE_TYPE_REGION2) return PGM_TRANSLATION_SPEC; if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl) return PGM_REGION_THIRD_TRANS; if (sg->edat_level >= 1) *dat_protection |= rste.p; ptr = rste.rto * PAGE_SIZE; shadow_r3t: rste.p |= *dat_protection; rc = gmap_shadow_r3t(sg, saddr, rste.val, *fake); if (rc) return rc; kvm->stat.gmap_shadow_r2_entry++; } fallthrough; case ASCE_TYPE_REGION3: { union region3_table_entry rtte; if (*fake) { ptr += vaddr.rtx * _REGION3_SIZE; rtte.val = ptr; goto shadow_sgt; } *pgt = ptr + vaddr.rtx * 8; rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val); if (rc) return rc; if (rtte.i) return PGM_REGION_THIRD_TRANS; if (rtte.tt != TABLE_TYPE_REGION3) return PGM_TRANSLATION_SPEC; if (rtte.cr && asce.p && sg->edat_level >= 2) return PGM_TRANSLATION_SPEC; if (rtte.fc && sg->edat_level >= 2) { *dat_protection |= rtte.fc0.p; *fake = 1; ptr = rtte.fc1.rfaa * _REGION3_SIZE; rtte.val = ptr; goto shadow_sgt; } if (vaddr.sx01 < rtte.fc0.tf || vaddr.sx01 > rtte.fc0.tl) return PGM_SEGMENT_TRANSLATION; if (sg->edat_level >= 1) *dat_protection |= rtte.fc0.p; ptr = rtte.fc0.sto * PAGE_SIZE; shadow_sgt: rtte.fc0.p |= *dat_protection; rc = gmap_shadow_sgt(sg, saddr, rtte.val, *fake); if (rc) return rc; kvm->stat.gmap_shadow_r3_entry++; } fallthrough; case ASCE_TYPE_SEGMENT: { union segment_table_entry ste; if (*fake) { ptr += vaddr.sx * _SEGMENT_SIZE; ste.val = ptr; goto shadow_pgt; } *pgt = ptr + vaddr.sx * 8; rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val); if (rc) return rc; if (ste.i) return PGM_SEGMENT_TRANSLATION; if (ste.tt != TABLE_TYPE_SEGMENT) return PGM_TRANSLATION_SPEC; if (ste.cs && asce.p) return PGM_TRANSLATION_SPEC; *dat_protection |= ste.fc0.p; if (ste.fc && sg->edat_level >= 1) { *fake = 1; ptr = ste.fc1.sfaa * _SEGMENT_SIZE; ste.val = ptr; goto shadow_pgt; } ptr = ste.fc0.pto * (PAGE_SIZE / 2); shadow_pgt: ste.fc0.p |= *dat_protection; rc = gmap_shadow_pgt(sg, saddr, ste.val, *fake); if (rc) return rc; kvm->stat.gmap_shadow_sg_entry++; } } /* Return the parent address of the page table */ *pgt = ptr; return 0; } /** * kvm_s390_shadow_fault - handle fault on a shadow page table * @vcpu: virtual cpu * @sg: pointer to the shadow guest address space structure * @saddr: faulting address in the shadow gmap * @datptr: will contain the address of the faulting DAT table entry, or of * the valid leaf, plus some flags * * Returns: - 0 if the shadow fault was successfully resolved * - > 0 (pgm exception code) on exceptions while faulting * - -EAGAIN if the caller can retry immediately * - -EFAULT when accessing invalid guest addresses * - -ENOMEM if out of memory */ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, unsigned long saddr, unsigned long *datptr) { union vaddress vaddr; union page_table_entry pte; unsigned long pgt = 0; int dat_protection, fake; int rc; mmap_read_lock(sg->mm); /* * We don't want any guest-2 tables to change - so the parent * tables/pointers we read stay valid - unshadowing is however * always possible - only guest_table_lock protects us. */ ipte_lock(vcpu->kvm); rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake); if (rc) rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection, &fake); vaddr.addr = saddr; if (fake) { pte.val = pgt + vaddr.px * PAGE_SIZE; goto shadow_page; } switch (rc) { case PGM_SEGMENT_TRANSLATION: case PGM_REGION_THIRD_TRANS: case PGM_REGION_SECOND_TRANS: case PGM_REGION_FIRST_TRANS: pgt |= PEI_NOT_PTE; break; case 0: pgt += vaddr.px * 8; rc = gmap_read_table(sg->parent, pgt, &pte.val); } if (datptr) *datptr = pgt | dat_protection * PEI_DAT_PROT; if (!rc && pte.i) rc = PGM_PAGE_TRANSLATION; if (!rc && pte.z) rc = PGM_TRANSLATION_SPEC; shadow_page: pte.p |= dat_protection; if (!rc) rc = gmap_shadow_page(sg, saddr, __pte(pte.val)); vcpu->kvm->stat.gmap_shadow_pg_entry++; ipte_unlock(vcpu->kvm); mmap_read_unlock(sg->mm); return rc; }