diff options
Diffstat (limited to 'arch/s390/kvm/vsie.c')
| -rw-r--r-- | arch/s390/kvm/vsie.c | 1091 |
1 files changed, 1091 insertions, 0 deletions
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c new file mode 100644 index 000000000..d8673e243 --- /dev/null +++ b/arch/s390/kvm/vsie.c @@ -0,0 +1,1091 @@ +/* + * kvm nested virtualization support for s390x + * + * Copyright IBM Corp. 2016 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License (version 2 only) + * as published by the Free Software Foundation. + * + * Author(s): David Hildenbrand <dahi@linux.vnet.ibm.com> + */ +#include <linux/vmalloc.h> +#include <linux/kvm_host.h> +#include <linux/bug.h> +#include <linux/list.h> +#include <linux/bitmap.h> +#include <asm/gmap.h> +#include <asm/mmu_context.h> +#include <asm/sclp.h> +#include <asm/nmi.h> +#include <asm/dis.h> +#include "kvm-s390.h" +#include "gaccess.h" + +struct vsie_page { + struct kvm_s390_sie_block scb_s; /* 0x0000 */ + /* the pinned originial scb */ + struct kvm_s390_sie_block *scb_o; /* 0x0200 */ + /* the shadow gmap in use by the vsie_page */ + struct gmap *gmap; /* 0x0208 */ + /* address of the last reported fault to guest2 */ + unsigned long fault_addr; /* 0x0210 */ + __u8 reserved[0x0700 - 0x0218]; /* 0x0218 */ + struct kvm_s390_crypto_cb crycb; /* 0x0700 */ + __u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE]; /* 0x0800 */ +} __packed; + +/* 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; + + 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; + u32 crycb_addr = scb_o->crycbd & 0x7ffffff8U; + unsigned long *b1, *b2; + u8 ecb3_flags; + + scb_s->crycbd = 0; + if (!(scb_o->crycbd & 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; + __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 && (scb_o->ibc & 0x0fffU)) { + scb_s->ibc = scb_o->ibc & 0x0fffU; + /* 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; + bool had_tx = scb_s->ecb & 0x10U; + 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. + */ + 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 = 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 != scb_o->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 = scb_o->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 & 0x01002000U; + /* 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 & 0x02U; + /* transactional execution */ + if (test_kvm_facility(vcpu->kvm, 73)) { + /* remap the prefix is tx is toggled on */ + if ((scb_o->ecb & 0x10U) && !had_tx) + prefix_unmapped(vsie_page); + scb_s->ecb |= scb_o->ecb & 0x10U; + } + /* SIMD */ + if (test_kvm_facility(vcpu->kvm, 129)) { + scb_s->eca |= scb_o->eca & 0x00020000U; + scb_s->ecd |= scb_o->ecd & 0x20000000U; + } + /* Run-time-Instrumentation */ + if (test_kvm_facility(vcpu->kvm, 64)) + scb_s->ecb3 |= scb_o->ecb3 & 0x01U; + if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIIF)) + scb_s->eca |= scb_o->eca & 0x00000001U; + if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IB)) + scb_s->eca |= scb_o->eca & 0x40000000U; + if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI)) + scb_s->eca |= scb_o->eca & 0x80000000U; + + 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 & 0x10U)) + 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 + * - -ENOMEM if out of memory + */ +static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa) +{ + struct page *page; + hva_t hva; + int rc; + + hva = gfn_to_hva(kvm, gpa_to_gfn(gpa)); + if (kvm_is_error_hva(hva)) + return -EINVAL; + rc = get_user_pages_fast(hva, 1, 1, &page); + if (rc < 0) + return rc; + else if (rc != 1) + return -ENOMEM; + *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) +{ + struct page *page; + + page = virt_to_page(hpa); + set_page_dirty_lock(page); + put_page(page); + /* 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_o = vsie_page->scb_o; + struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; + hpa_t hpa; + gpa_t gpa; + + hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol; + if (hpa) { + gpa = scb_o->scaol & ~0xfUL; + if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO)) + gpa |= (u64) scb_o->scaoh << 32; + unpin_guest_page(vcpu->kvm, gpa, hpa); + scb_s->scaol = 0; + scb_s->scaoh = 0; + } + + hpa = scb_s->itdba; + if (hpa) { + gpa = scb_o->itdba & ~0xffUL; + unpin_guest_page(vcpu->kvm, gpa, hpa); + scb_s->itdba = 0; + } + + hpa = scb_s->gvrd; + if (hpa) { + gpa = scb_o->gvrd & ~0x1ffUL; + unpin_guest_page(vcpu->kvm, gpa, hpa); + scb_s->gvrd = 0; + } + + hpa = scb_s->riccbd; + if (hpa) { + gpa = scb_o->riccbd & ~0x3fUL; + unpin_guest_page(vcpu->kvm, gpa, hpa); + scb_s->riccbd = 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 = scb_o->scaol & ~0xfUL; + if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO)) + gpa |= (u64) 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 == -EINVAL) + rc = set_validity_icpt(scb_s, 0x0034U); + } + if (rc) + goto unpin; + scb_s->scaoh = (u32)((u64)hpa >> 32); + scb_s->scaol = (u32)(u64)hpa; + } + + gpa = scb_o->itdba & ~0xffUL; + if (gpa && (scb_s->ecb & 0x10U)) { + 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 == -EINVAL) + rc = set_validity_icpt(scb_s, 0x0080U); + if (rc) + goto unpin; + scb_s->itdba = hpa; + } + + gpa = scb_o->gvrd & ~0x1ffUL; + if (gpa && (scb_s->eca & 0x00020000U) && + !(scb_s->ecd & 0x20000000U)) { + 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 == -EINVAL) + rc = set_validity_icpt(scb_s, 0x1310U); + if (rc) + goto unpin; + scb_s->gvrd = hpa; + } + + gpa = scb_o->riccbd & ~0x3fUL; + if (gpa && (scb_s->ecb3 & 0x01U)) { + 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 == -EINVAL) + rc = set_validity_icpt(scb_s, 0x0043U); + /* Validity 0x0044 will be checked by SIE */ + if (rc) + goto unpin; + scb_s->riccbd = hpa; + } + 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 + * - -ENOMEM if out of memory + */ +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 == -EINVAL) { + rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); + if (!rc) + rc = 1; + } + if (!rc) + vsie_page->scb_o = (struct kvm_s390_sie_block *) hpa; + return rc; +} + +/* + * 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 = 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 > 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. + */ + atomic_or(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags); + /* + * 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; + preempt_enable(); +} + +/* + * Unregister a shadow scb from a VCPU. + */ +static void unregister_shadow_scb(struct kvm_vcpu *vcpu) +{ + atomic_andnot(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags); + 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) != 4096); + 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); + } +} |