// SPDX-License-Identifier: GPL-2.0 /* * kvm nested virtualization support for s390x * * Copyright IBM Corp. 2016 * * Author(s): David Hildenbrand */ #include #include #include #include #include #include #include #include #include #include #include #include "kvm-s390.h" #include "gaccess.h" struct vsie_page { struct kvm_s390_sie_block scb_s; /* 0x0000 */ /* * the backup info for machine check. ensure it's at * the same offset as that in struct sie_page! */ struct mcck_volatile_info mcck_info; /* 0x0200 */ /* * The pinned original scb. Be aware that other VCPUs can modify * it while we read from it. Values that are used for conditions or * are reused conditionally, should be accessed via READ_ONCE. */ struct kvm_s390_sie_block *scb_o; /* 0x0218 */ /* the shadow gmap in use by the vsie_page */ struct gmap *gmap; /* 0x0220 */ /* address of the last reported fault to guest2 */ unsigned long fault_addr; /* 0x0228 */ /* calculated guest addresses of satellite control blocks */ gpa_t sca_gpa; /* 0x0230 */ gpa_t itdba_gpa; /* 0x0238 */ gpa_t gvrd_gpa; /* 0x0240 */ gpa_t riccbd_gpa; /* 0x0248 */ gpa_t sdnx_gpa; /* 0x0250 */ __u8 reserved[0x0700 - 0x0258]; /* 0x0258 */ struct kvm_s390_crypto_cb crycb; /* 0x0700 */ __u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE]; /* 0x0800 */ }; /* trigger a validity icpt for the given scb */ static int set_validity_icpt(struct kvm_s390_sie_block *scb, __u16 reason_code) { scb->ipa = 0x1000; scb->ipb = ((__u32) reason_code) << 16; scb->icptcode = ICPT_VALIDITY; return 1; } /* mark the prefix as unmapped, this will block the VSIE */ static void prefix_unmapped(struct vsie_page *vsie_page) { atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20); } /* mark the prefix as unmapped and wait until the VSIE has been left */ static void prefix_unmapped_sync(struct vsie_page *vsie_page) { prefix_unmapped(vsie_page); if (vsie_page->scb_s.prog0c & PROG_IN_SIE) atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags); while (vsie_page->scb_s.prog0c & PROG_IN_SIE) cpu_relax(); } /* mark the prefix as mapped, this will allow the VSIE to run */ static void prefix_mapped(struct vsie_page *vsie_page) { atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20); } /* test if the prefix is mapped into the gmap shadow */ static int prefix_is_mapped(struct vsie_page *vsie_page) { return !(atomic_read(&vsie_page->scb_s.prog20) & PROG_REQUEST); } /* copy the updated intervention request bits into the shadow scb */ static void update_intervention_requests(struct vsie_page *vsie_page) { const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT; int cpuflags; cpuflags = atomic_read(&vsie_page->scb_o->cpuflags); atomic_andnot(bits, &vsie_page->scb_s.cpuflags); atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags); } /* shadow (filter and validate) the cpuflags */ static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; int newflags, cpuflags = atomic_read(&scb_o->cpuflags); /* we don't allow ESA/390 guests */ if (!(cpuflags & CPUSTAT_ZARCH)) return set_validity_icpt(scb_s, 0x0001U); if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS)) return set_validity_icpt(scb_s, 0x0001U); else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR)) return set_validity_icpt(scb_s, 0x0007U); /* intervention requests will be set later */ newflags = CPUSTAT_ZARCH; if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8)) newflags |= CPUSTAT_GED; if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) { if (cpuflags & CPUSTAT_GED) return set_validity_icpt(scb_s, 0x0001U); newflags |= CPUSTAT_GED2; } if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GPERE)) newflags |= cpuflags & CPUSTAT_P; if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GSLS)) newflags |= cpuflags & CPUSTAT_SM; if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IBS)) newflags |= cpuflags & CPUSTAT_IBS; if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_KSS)) newflags |= cpuflags & CPUSTAT_KSS; atomic_set(&scb_s->cpuflags, newflags); return 0; } /* * Create a shadow copy of the crycb block and setup key wrapping, if * requested for guest 3 and enabled for guest 2. * * We only accept format-1 (no AP in g2), but convert it into format-2 * There is nothing to do for format-0. * * Returns: - 0 if shadowed or nothing to do * - > 0 if control has to be given to guest 2 */ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; const uint32_t crycbd_o = READ_ONCE(scb_o->crycbd); const u32 crycb_addr = crycbd_o & 0x7ffffff8U; unsigned long *b1, *b2; u8 ecb3_flags; scb_s->crycbd = 0; if (!(crycbd_o & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1)) return 0; /* format-1 is supported with message-security-assist extension 3 */ if (!test_kvm_facility(vcpu->kvm, 76)) return 0; /* we may only allow it if enabled for guest 2 */ ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 & (ECB3_AES | ECB3_DEA); if (!ecb3_flags) return 0; if ((crycb_addr & PAGE_MASK) != ((crycb_addr + 128) & PAGE_MASK)) return set_validity_icpt(scb_s, 0x003CU); else if (!crycb_addr) return set_validity_icpt(scb_s, 0x0039U); /* copy only the wrapping keys */ if (read_guest_real(vcpu, crycb_addr + 72, &vsie_page->crycb, 56)) return set_validity_icpt(scb_s, 0x0035U); scb_s->ecb3 |= ecb3_flags; scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT1 | CRYCB_FORMAT2; /* xor both blocks in one run */ b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask; b2 = (unsigned long *) vcpu->kvm->arch.crypto.crycb->dea_wrapping_key_mask; /* as 56%8 == 0, bitmap_xor won't overwrite any data */ bitmap_xor(b1, b1, b2, BITS_PER_BYTE * 56); return 0; } /* shadow (round up/down) the ibc to avoid validity icpt */ static void prepare_ibc(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; /* READ_ONCE does not work on bitfields - use a temporary variable */ const uint32_t __new_ibc = scb_o->ibc; const uint32_t new_ibc = READ_ONCE(__new_ibc) & 0x0fffU; __u64 min_ibc = (sclp.ibc >> 16) & 0x0fffU; scb_s->ibc = 0; /* ibc installed in g2 and requested for g3 */ if (vcpu->kvm->arch.model.ibc && new_ibc) { scb_s->ibc = new_ibc; /* takte care of the minimum ibc level of the machine */ if (scb_s->ibc < min_ibc) scb_s->ibc = min_ibc; /* take care of the maximum ibc level set for the guest */ if (scb_s->ibc > vcpu->kvm->arch.model.ibc) scb_s->ibc = vcpu->kvm->arch.model.ibc; } } /* unshadow the scb, copying parameters back to the real scb */ static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; /* interception */ scb_o->icptcode = scb_s->icptcode; scb_o->icptstatus = scb_s->icptstatus; scb_o->ipa = scb_s->ipa; scb_o->ipb = scb_s->ipb; scb_o->gbea = scb_s->gbea; /* timer */ scb_o->cputm = scb_s->cputm; scb_o->ckc = scb_s->ckc; scb_o->todpr = scb_s->todpr; /* guest state */ scb_o->gpsw = scb_s->gpsw; scb_o->gg14 = scb_s->gg14; scb_o->gg15 = scb_s->gg15; memcpy(scb_o->gcr, scb_s->gcr, 128); scb_o->pp = scb_s->pp; /* interrupt intercept */ switch (scb_s->icptcode) { case ICPT_PROGI: case ICPT_INSTPROGI: case ICPT_EXTINT: memcpy((void *)((u64)scb_o + 0xc0), (void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0); break; case ICPT_PARTEXEC: /* MVPG only */ memcpy((void *)((u64)scb_o + 0xc0), (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0); break; } if (scb_s->ihcpu != 0xffffU) scb_o->ihcpu = scb_s->ihcpu; } /* * Setup the shadow scb by copying and checking the relevant parts of the g2 * provided scb. * * Returns: - 0 if the scb has been shadowed * - > 0 if control has to be given to guest 2 */ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; /* READ_ONCE does not work on bitfields - use a temporary variable */ const uint32_t __new_prefix = scb_o->prefix; const uint32_t new_prefix = READ_ONCE(__new_prefix); const bool wants_tx = READ_ONCE(scb_o->ecb) & ECB_TE; bool had_tx = scb_s->ecb & ECB_TE; unsigned long new_mso = 0; int rc; /* make sure we don't have any leftovers when reusing the scb */ scb_s->icptcode = 0; scb_s->eca = 0; scb_s->ecb = 0; scb_s->ecb2 = 0; scb_s->ecb3 = 0; scb_s->ecd = 0; scb_s->fac = 0; rc = prepare_cpuflags(vcpu, vsie_page); if (rc) goto out; /* timer */ scb_s->cputm = scb_o->cputm; scb_s->ckc = scb_o->ckc; scb_s->todpr = scb_o->todpr; scb_s->epoch = scb_o->epoch; /* guest state */ scb_s->gpsw = scb_o->gpsw; scb_s->gg14 = scb_o->gg14; scb_s->gg15 = scb_o->gg15; memcpy(scb_s->gcr, scb_o->gcr, 128); scb_s->pp = scb_o->pp; /* interception / execution handling */ scb_s->gbea = scb_o->gbea; scb_s->lctl = scb_o->lctl; scb_s->svcc = scb_o->svcc; scb_s->ictl = scb_o->ictl; /* * SKEY handling functions can't deal with false setting of PTE invalid * bits. Therefore we cannot provide interpretation and would later * have to provide own emulation handlers. */ if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_KSS)) scb_s->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE; scb_s->icpua = scb_o->icpua; if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_SM)) new_mso = READ_ONCE(scb_o->mso) & 0xfffffffffff00000UL; /* if the hva of the prefix changes, we have to remap the prefix */ if (scb_s->mso != new_mso || scb_s->prefix != new_prefix) prefix_unmapped(vsie_page); /* SIE will do mso/msl validity and exception checks for us */ scb_s->msl = scb_o->msl & 0xfffffffffff00000UL; scb_s->mso = new_mso; scb_s->prefix = new_prefix; /* We have to definetly flush the tlb if this scb never ran */ if (scb_s->ihcpu != 0xffffU) scb_s->ihcpu = scb_o->ihcpu; /* MVPG and Protection Exception Interpretation are always available */ scb_s->eca |= scb_o->eca & (ECA_MVPGI | ECA_PROTEXCI); /* Host-protection-interruption introduced with ESOP */ if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_ESOP)) scb_s->ecb |= scb_o->ecb & ECB_HOSTPROTINT; /* transactional execution */ if (test_kvm_facility(vcpu->kvm, 73) && wants_tx) { /* remap the prefix is tx is toggled on */ if (!had_tx) prefix_unmapped(vsie_page); scb_s->ecb |= ECB_TE; } /* SIMD */ if (test_kvm_facility(vcpu->kvm, 129)) { scb_s->eca |= scb_o->eca & ECA_VX; scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT; } /* Run-time-Instrumentation */ if (test_kvm_facility(vcpu->kvm, 64)) scb_s->ecb3 |= scb_o->ecb3 & ECB3_RI; /* Instruction Execution Prevention */ if (test_kvm_facility(vcpu->kvm, 130)) scb_s->ecb2 |= scb_o->ecb2 & ECB2_IEP; /* Guarded Storage */ if (test_kvm_facility(vcpu->kvm, 133)) { scb_s->ecb |= scb_o->ecb & ECB_GS; scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT; } if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIIF)) scb_s->eca |= scb_o->eca & ECA_SII; if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IB)) scb_s->eca |= scb_o->eca & ECA_IB; if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI)) scb_s->eca |= scb_o->eca & ECA_CEI; /* Epoch Extension */ if (test_kvm_facility(vcpu->kvm, 139)) scb_s->ecd |= scb_o->ecd & ECD_MEF; prepare_ibc(vcpu, vsie_page); rc = shadow_crycb(vcpu, vsie_page); out: if (rc) unshadow_scb(vcpu, vsie_page); return rc; } void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start, unsigned long end) { struct kvm *kvm = gmap->private; struct vsie_page *cur; unsigned long prefix; struct page *page; int i; if (!gmap_is_shadow(gmap)) return; if (start >= 1UL << 31) /* We are only interested in prefix pages */ return; /* * Only new shadow blocks are added to the list during runtime, * therefore we can safely reference them all the time. */ for (i = 0; i < kvm->arch.vsie.page_count; i++) { page = READ_ONCE(kvm->arch.vsie.pages[i]); if (!page) continue; cur = page_to_virt(page); if (READ_ONCE(cur->gmap) != gmap) continue; prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT; /* with mso/msl, the prefix lies at an offset */ prefix += cur->scb_s.mso; if (prefix <= end && start <= prefix + 2 * PAGE_SIZE - 1) prefix_unmapped_sync(cur); } } /* * Map the first prefix page and if tx is enabled also the second prefix page. * * The prefix will be protected, a gmap notifier will inform about unmaps. * The shadow scb must not be executed until the prefix is remapped, this is * guaranteed by properly handling PROG_REQUEST. * * Returns: - 0 on if successfully mapped or already mapped * - > 0 if control has to be given to guest 2 * - -EAGAIN if the caller can retry immediately * - -ENOMEM if out of memory */ static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; u64 prefix = scb_s->prefix << GUEST_PREFIX_SHIFT; int rc; if (prefix_is_mapped(vsie_page)) return 0; /* mark it as mapped so we can catch any concurrent unmappers */ prefix_mapped(vsie_page); /* with mso/msl, the prefix lies at offset *mso* */ prefix += scb_s->mso; rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix); if (!rc && (scb_s->ecb & ECB_TE)) rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix + PAGE_SIZE); /* * We don't have to mprotect, we will be called for all unshadows. * SIE will detect if protection applies and trigger a validity. */ if (rc) prefix_unmapped(vsie_page); if (rc > 0 || rc == -EFAULT) rc = set_validity_icpt(scb_s, 0x0037U); return rc; } /* * Pin the guest page given by gpa and set hpa to the pinned host address. * Will always be pinned writable. * * Returns: - 0 on success * - -EINVAL if the gpa is not valid guest storage */ static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa) { struct page *page; page = gfn_to_page(kvm, gpa_to_gfn(gpa)); if (is_error_page(page)) return -EINVAL; *hpa = (hpa_t) page_to_virt(page) + (gpa & ~PAGE_MASK); return 0; } /* Unpins a page previously pinned via pin_guest_page, marking it as dirty. */ static void unpin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t hpa) { kvm_release_pfn_dirty(hpa >> PAGE_SHIFT); /* mark the page always as dirty for migration */ mark_page_dirty(kvm, gpa_to_gfn(gpa)); } /* unpin all blocks previously pinned by pin_blocks(), marking them dirty */ static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; hpa_t hpa; hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol; if (hpa) { unpin_guest_page(vcpu->kvm, vsie_page->sca_gpa, hpa); vsie_page->sca_gpa = 0; scb_s->scaol = 0; scb_s->scaoh = 0; } hpa = scb_s->itdba; if (hpa) { unpin_guest_page(vcpu->kvm, vsie_page->itdba_gpa, hpa); vsie_page->itdba_gpa = 0; scb_s->itdba = 0; } hpa = scb_s->gvrd; if (hpa) { unpin_guest_page(vcpu->kvm, vsie_page->gvrd_gpa, hpa); vsie_page->gvrd_gpa = 0; scb_s->gvrd = 0; } hpa = scb_s->riccbd; if (hpa) { unpin_guest_page(vcpu->kvm, vsie_page->riccbd_gpa, hpa); vsie_page->riccbd_gpa = 0; scb_s->riccbd = 0; } hpa = scb_s->sdnxo; if (hpa) { unpin_guest_page(vcpu->kvm, vsie_page->sdnx_gpa, hpa); vsie_page->sdnx_gpa = 0; scb_s->sdnxo = 0; } } /* * Instead of shadowing some blocks, we can simply forward them because the * addresses in the scb are 64 bit long. * * This works as long as the data lies in one page. If blocks ever exceed one * page, we have to fall back to shadowing. * * As we reuse the sca, the vcpu pointers contained in it are invalid. We must * therefore not enable any facilities that access these pointers (e.g. SIGPIF). * * Returns: - 0 if all blocks were pinned. * - > 0 if control has to be given to guest 2 * - -ENOMEM if out of memory */ static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; hpa_t hpa; gpa_t gpa; int rc = 0; gpa = READ_ONCE(scb_o->scaol) & ~0xfUL; if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO)) gpa |= (u64) READ_ONCE(scb_o->scaoh) << 32; if (gpa) { if (!(gpa & ~0x1fffUL)) rc = set_validity_icpt(scb_s, 0x0038U); else if ((gpa & ~0x1fffUL) == kvm_s390_get_prefix(vcpu)) rc = set_validity_icpt(scb_s, 0x0011U); else if ((gpa & PAGE_MASK) != ((gpa + sizeof(struct bsca_block) - 1) & PAGE_MASK)) rc = set_validity_icpt(scb_s, 0x003bU); if (!rc) { rc = pin_guest_page(vcpu->kvm, gpa, &hpa); if (rc) rc = set_validity_icpt(scb_s, 0x0034U); } if (rc) goto unpin; vsie_page->sca_gpa = gpa; scb_s->scaoh = (u32)((u64)hpa >> 32); scb_s->scaol = (u32)(u64)hpa; } gpa = READ_ONCE(scb_o->itdba) & ~0xffUL; if (gpa && (scb_s->ecb & ECB_TE)) { if (!(gpa & ~0x1fffU)) { rc = set_validity_icpt(scb_s, 0x0080U); goto unpin; } /* 256 bytes cannot cross page boundaries */ rc = pin_guest_page(vcpu->kvm, gpa, &hpa); if (rc) { rc = set_validity_icpt(scb_s, 0x0080U); goto unpin; } vsie_page->itdba_gpa = gpa; scb_s->itdba = hpa; } gpa = READ_ONCE(scb_o->gvrd) & ~0x1ffUL; if (gpa && (scb_s->eca & ECA_VX) && !(scb_s->ecd & ECD_HOSTREGMGMT)) { if (!(gpa & ~0x1fffUL)) { rc = set_validity_icpt(scb_s, 0x1310U); goto unpin; } /* * 512 bytes vector registers cannot cross page boundaries * if this block gets bigger, we have to shadow it. */ rc = pin_guest_page(vcpu->kvm, gpa, &hpa); if (rc) { rc = set_validity_icpt(scb_s, 0x1310U); goto unpin; } vsie_page->gvrd_gpa = gpa; scb_s->gvrd = hpa; } gpa = READ_ONCE(scb_o->riccbd) & ~0x3fUL; if (gpa && (scb_s->ecb3 & ECB3_RI)) { if (!(gpa & ~0x1fffUL)) { rc = set_validity_icpt(scb_s, 0x0043U); goto unpin; } /* 64 bytes cannot cross page boundaries */ rc = pin_guest_page(vcpu->kvm, gpa, &hpa); if (rc) { rc = set_validity_icpt(scb_s, 0x0043U); goto unpin; } /* Validity 0x0044 will be checked by SIE */ vsie_page->riccbd_gpa = gpa; scb_s->riccbd = hpa; } if ((scb_s->ecb & ECB_GS) && !(scb_s->ecd & ECD_HOSTREGMGMT)) { unsigned long sdnxc; gpa = READ_ONCE(scb_o->sdnxo) & ~0xfUL; sdnxc = READ_ONCE(scb_o->sdnxo) & 0xfUL; if (!gpa || !(gpa & ~0x1fffUL)) { rc = set_validity_icpt(scb_s, 0x10b0U); goto unpin; } if (sdnxc < 6 || sdnxc > 12) { rc = set_validity_icpt(scb_s, 0x10b1U); goto unpin; } if (gpa & ((1 << sdnxc) - 1)) { rc = set_validity_icpt(scb_s, 0x10b2U); goto unpin; } /* Due to alignment rules (checked above) this cannot * cross page boundaries */ rc = pin_guest_page(vcpu->kvm, gpa, &hpa); if (rc) { rc = set_validity_icpt(scb_s, 0x10b0U); goto unpin; } vsie_page->sdnx_gpa = gpa; scb_s->sdnxo = hpa | sdnxc; } return 0; unpin: unpin_blocks(vcpu, vsie_page); return rc; } /* unpin the scb provided by guest 2, marking it as dirty */ static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, gpa_t gpa) { hpa_t hpa = (hpa_t) vsie_page->scb_o; if (hpa) unpin_guest_page(vcpu->kvm, gpa, hpa); vsie_page->scb_o = NULL; } /* * Pin the scb at gpa provided by guest 2 at vsie_page->scb_o. * * Returns: - 0 if the scb was pinned. * - > 0 if control has to be given to guest 2 */ static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, gpa_t gpa) { hpa_t hpa; int rc; rc = pin_guest_page(vcpu->kvm, gpa, &hpa); if (rc) { rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); WARN_ON_ONCE(rc); return 1; } vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa; return 0; } /* * Inject a fault into guest 2. * * Returns: - > 0 if control has to be given to guest 2 * < 0 if an error occurred during injection. */ static int inject_fault(struct kvm_vcpu *vcpu, __u16 code, __u64 vaddr, bool write_flag) { struct kvm_s390_pgm_info pgm = { .code = code, .trans_exc_code = /* 0-51: virtual address */ (vaddr & 0xfffffffffffff000UL) | /* 52-53: store / fetch */ (((unsigned int) !write_flag) + 1) << 10, /* 62-63: asce id (alway primary == 0) */ .exc_access_id = 0, /* always primary */ .op_access_id = 0, /* not MVPG */ }; int rc; if (code == PGM_PROTECTION) pgm.trans_exc_code |= 0x4UL; rc = kvm_s390_inject_prog_irq(vcpu, &pgm); return rc ? rc : 1; } /* * Handle a fault during vsie execution on a gmap shadow. * * Returns: - 0 if the fault was resolved * - > 0 if control has to be given to guest 2 * - < 0 if an error occurred */ static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { int rc; if (current->thread.gmap_int_code == PGM_PROTECTION) /* we can directly forward all protection exceptions */ return inject_fault(vcpu, PGM_PROTECTION, current->thread.gmap_addr, 1); rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, current->thread.gmap_addr); if (rc > 0) { rc = inject_fault(vcpu, rc, current->thread.gmap_addr, current->thread.gmap_write_flag); if (rc >= 0) vsie_page->fault_addr = current->thread.gmap_addr; } return rc; } /* * Retry the previous fault that required guest 2 intervention. This avoids * one superfluous SIE re-entry and direct exit. * * Will ignore any errors. The next SIE fault will do proper fault handling. */ static void handle_last_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { if (vsie_page->fault_addr) kvm_s390_shadow_fault(vcpu, vsie_page->gmap, vsie_page->fault_addr); vsie_page->fault_addr = 0; } static inline void clear_vsie_icpt(struct vsie_page *vsie_page) { vsie_page->scb_s.icptcode = 0; } /* rewind the psw and clear the vsie icpt, so we can retry execution */ static void retry_vsie_icpt(struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; int ilen = insn_length(scb_s->ipa >> 8); /* take care of EXECUTE instructions */ if (scb_s->icptstatus & 1) { ilen = (scb_s->icptstatus >> 4) & 0x6; if (!ilen) ilen = 4; } scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, ilen); clear_vsie_icpt(vsie_page); } /* * Try to shadow + enable the guest 2 provided facility list. * Retry instruction execution if enabled for and provided by guest 2. * * Returns: - 0 if handled (retry or guest 2 icpt) * - > 0 if control has to be given to guest 2 */ static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; __u32 fac = READ_ONCE(vsie_page->scb_o->fac) & 0x7ffffff8U; if (fac && test_kvm_facility(vcpu->kvm, 7)) { retry_vsie_icpt(vsie_page); if (read_guest_real(vcpu, fac, &vsie_page->fac, sizeof(vsie_page->fac))) return set_validity_icpt(scb_s, 0x1090U); scb_s->fac = (__u32)(__u64) &vsie_page->fac; } return 0; } /* * Run the vsie on a shadow scb and a shadow gmap, without any further * sanity checks, handling SIE faults. * * Returns: - 0 everything went fine * - > 0 if control has to be given to guest 2 * - < 0 if an error occurred */ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; int rc; handle_last_fault(vcpu, vsie_page); if (need_resched()) schedule(); if (test_cpu_flag(CIF_MCCK_PENDING)) s390_handle_mcck(); srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); local_irq_disable(); guest_enter_irqoff(); local_irq_enable(); rc = sie64a(scb_s, vcpu->run->s.regs.gprs); local_irq_disable(); guest_exit_irqoff(); local_irq_enable(); vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); if (rc == -EINTR) { VCPU_EVENT(vcpu, 3, "%s", "machine check"); kvm_s390_reinject_machine_check(vcpu, &vsie_page->mcck_info); return 0; } if (rc > 0) rc = 0; /* we could still have an icpt */ else if (rc == -EFAULT) return handle_fault(vcpu, vsie_page); switch (scb_s->icptcode) { case ICPT_INST: if (scb_s->ipa == 0xb2b0) rc = handle_stfle(vcpu, vsie_page); break; case ICPT_STOP: /* stop not requested by g2 - must have been a kick */ if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT)) clear_vsie_icpt(vsie_page); break; case ICPT_VALIDITY: if ((scb_s->ipa & 0xf000) != 0xf000) scb_s->ipa += 0x1000; break; } return rc; } static void release_gmap_shadow(struct vsie_page *vsie_page) { if (vsie_page->gmap) gmap_put(vsie_page->gmap); WRITE_ONCE(vsie_page->gmap, NULL); prefix_unmapped(vsie_page); } static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { unsigned long asce; union ctlreg0 cr0; struct gmap *gmap; int edat; asce = vcpu->arch.sie_block->gcr[1]; cr0.val = vcpu->arch.sie_block->gcr[0]; edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8); edat += edat && test_kvm_facility(vcpu->kvm, 78); /* * ASCE or EDAT could have changed since last icpt, or the gmap * we're holding has been unshadowed. If the gmap is still valid, * we can safely reuse it. */ if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat)) return 0; /* release the old shadow - if any, and mark the prefix as unmapped */ release_gmap_shadow(vsie_page); gmap = gmap_shadow(vcpu->arch.gmap, asce, edat); if (IS_ERR(gmap)) return PTR_ERR(gmap); gmap->private = vcpu->kvm; WRITE_ONCE(vsie_page->gmap, gmap); return 0; } /* * Register the shadow scb at the VCPU, e.g. for kicking out of vsie. */ static void register_shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s); /* * External calls have to lead to a kick of the vcpu and * therefore the vsie -> Simulate Wait state. */ kvm_s390_set_cpuflags(vcpu, CPUSTAT_WAIT); /* * We have to adjust the g3 epoch by the g2 epoch. The epoch will * automatically be adjusted on tod clock changes via kvm_sync_clock. */ preempt_disable(); scb_s->epoch += vcpu->kvm->arch.epoch; if (scb_s->ecd & ECD_MEF) { scb_s->epdx += vcpu->kvm->arch.epdx; if (scb_s->epoch < vcpu->kvm->arch.epoch) scb_s->epdx += 1; } preempt_enable(); } /* * Unregister a shadow scb from a VCPU. */ static void unregister_shadow_scb(struct kvm_vcpu *vcpu) { kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT); WRITE_ONCE(vcpu->arch.vsie_block, NULL); } /* * Run the vsie on a shadowed scb, managing the gmap shadow, handling * prefix pages and faults. * * Returns: - 0 if no errors occurred * - > 0 if control has to be given to guest 2 * - -ENOMEM if out of memory */ static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; int rc = 0; while (1) { rc = acquire_gmap_shadow(vcpu, vsie_page); if (!rc) rc = map_prefix(vcpu, vsie_page); if (!rc) { gmap_enable(vsie_page->gmap); update_intervention_requests(vsie_page); rc = do_vsie_run(vcpu, vsie_page); gmap_enable(vcpu->arch.gmap); } atomic_andnot(PROG_BLOCK_SIE, &scb_s->prog20); if (rc == -EAGAIN) rc = 0; if (rc || scb_s->icptcode || signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0)) break; } if (rc == -EFAULT) { /* * Addressing exceptions are always presentes as intercepts. * As addressing exceptions are suppressing and our guest 3 PSW * points at the responsible instruction, we have to * forward the PSW and set the ilc. If we can't read guest 3 * instruction, we can use an arbitrary ilc. Let's always use * ilen = 4 for now, so we can avoid reading in guest 3 virtual * memory. (we could also fake the shadow so the hardware * handles it). */ scb_s->icptcode = ICPT_PROGI; scb_s->iprcc = PGM_ADDRESSING; scb_s->pgmilc = 4; scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4); } return rc; } /* * Get or create a vsie page for a scb address. * * Returns: - address of a vsie page (cached or new one) * - NULL if the same scb address is already used by another VCPU * - ERR_PTR(-ENOMEM) if out of memory */ static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr) { struct vsie_page *vsie_page; struct page *page; int nr_vcpus; rcu_read_lock(); page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9); rcu_read_unlock(); if (page) { if (page_ref_inc_return(page) == 2) return page_to_virt(page); page_ref_dec(page); } /* * We want at least #online_vcpus shadows, so every VCPU can execute * the VSIE in parallel. */ nr_vcpus = atomic_read(&kvm->online_vcpus); mutex_lock(&kvm->arch.vsie.mutex); if (kvm->arch.vsie.page_count < nr_vcpus) { page = alloc_page(GFP_KERNEL | __GFP_ZERO | GFP_DMA); if (!page) { mutex_unlock(&kvm->arch.vsie.mutex); return ERR_PTR(-ENOMEM); } page_ref_inc(page); kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page; kvm->arch.vsie.page_count++; } else { /* reuse an existing entry that belongs to nobody */ while (true) { page = kvm->arch.vsie.pages[kvm->arch.vsie.next]; if (page_ref_inc_return(page) == 2) break; page_ref_dec(page); kvm->arch.vsie.next++; kvm->arch.vsie.next %= nr_vcpus; } radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9); } page->index = addr; /* double use of the same address */ if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) { page_ref_dec(page); mutex_unlock(&kvm->arch.vsie.mutex); return NULL; } mutex_unlock(&kvm->arch.vsie.mutex); vsie_page = page_to_virt(page); memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block)); release_gmap_shadow(vsie_page); vsie_page->fault_addr = 0; vsie_page->scb_s.ihcpu = 0xffffU; return vsie_page; } /* put a vsie page acquired via get_vsie_page */ static void put_vsie_page(struct kvm *kvm, struct vsie_page *vsie_page) { struct page *page = pfn_to_page(__pa(vsie_page) >> PAGE_SHIFT); page_ref_dec(page); } int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu) { struct vsie_page *vsie_page; unsigned long scb_addr; int rc; vcpu->stat.instruction_sie++; if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIEF2)) return -EOPNOTSUPP; if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); BUILD_BUG_ON(sizeof(struct vsie_page) != PAGE_SIZE); scb_addr = kvm_s390_get_base_disp_s(vcpu, NULL); /* 512 byte alignment */ if (unlikely(scb_addr & 0x1ffUL)) return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0)) return 0; vsie_page = get_vsie_page(vcpu->kvm, scb_addr); if (IS_ERR(vsie_page)) return PTR_ERR(vsie_page); else if (!vsie_page) /* double use of sie control block - simply do nothing */ return 0; rc = pin_scb(vcpu, vsie_page, scb_addr); if (rc) goto out_put; rc = shadow_scb(vcpu, vsie_page); if (rc) goto out_unpin_scb; rc = pin_blocks(vcpu, vsie_page); if (rc) goto out_unshadow; register_shadow_scb(vcpu, vsie_page); rc = vsie_run(vcpu, vsie_page); unregister_shadow_scb(vcpu); unpin_blocks(vcpu, vsie_page); out_unshadow: unshadow_scb(vcpu, vsie_page); out_unpin_scb: unpin_scb(vcpu, vsie_page, scb_addr); out_put: put_vsie_page(vcpu->kvm, vsie_page); return rc < 0 ? rc : 0; } /* Init the vsie data structures. To be called when a vm is initialized. */ void kvm_s390_vsie_init(struct kvm *kvm) { mutex_init(&kvm->arch.vsie.mutex); INIT_RADIX_TREE(&kvm->arch.vsie.addr_to_page, GFP_KERNEL); } /* Destroy the vsie data structures. To be called when a vm is destroyed. */ void kvm_s390_vsie_destroy(struct kvm *kvm) { struct vsie_page *vsie_page; struct page *page; int i; mutex_lock(&kvm->arch.vsie.mutex); for (i = 0; i < kvm->arch.vsie.page_count; i++) { page = kvm->arch.vsie.pages[i]; kvm->arch.vsie.pages[i] = NULL; vsie_page = page_to_virt(page); release_gmap_shadow(vsie_page); /* free the radix tree entry */ radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9); __free_page(page); } kvm->arch.vsie.page_count = 0; mutex_unlock(&kvm->arch.vsie.mutex); } void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu) { struct kvm_s390_sie_block *scb = READ_ONCE(vcpu->arch.vsie_block); /* * Even if the VCPU lets go of the shadow sie block reference, it is * still valid in the cache. So we can safely kick it. */ if (scb) { atomic_or(PROG_BLOCK_SIE, &scb->prog20); if (scb->prog0c & PROG_IN_SIE) atomic_or(CPUSTAT_STOP_INT, &scb->cpuflags); } }