diff options
Diffstat (limited to 'arch/s390/kvm/diag.c')
| -rw-r--r-- | arch/s390/kvm/diag.c | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c new file mode 100644 index 000000000..3c65b8258 --- /dev/null +++ b/arch/s390/kvm/diag.c @@ -0,0 +1,307 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * handling diagnose instructions + * + * Copyright IBM Corp. 2008, 2020 + * + * Author(s): Carsten Otte <cotte@de.ibm.com> + * Christian Borntraeger <borntraeger@de.ibm.com> + */ + +#include <linux/kvm.h> +#include <linux/kvm_host.h> +#include <asm/gmap.h> +#include <asm/virtio-ccw.h> +#include "kvm-s390.h" +#include "trace.h" +#include "trace-s390.h" +#include "gaccess.h" + +static int diag_release_pages(struct kvm_vcpu *vcpu) +{ + unsigned long start, end; + unsigned long prefix = kvm_s390_get_prefix(vcpu); + + start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4]; + end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + PAGE_SIZE; + vcpu->stat.instruction_diagnose_10++; + + if (start & ~PAGE_MASK || end & ~PAGE_MASK || start >= end + || start < 2 * PAGE_SIZE) + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); + + VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end); + + /* + * We checked for start >= end above, so lets check for the + * fast path (no prefix swap page involved) + */ + if (end <= prefix || start >= prefix + 2 * PAGE_SIZE) { + gmap_discard(vcpu->arch.gmap, start, end); + } else { + /* + * This is slow path. gmap_discard will check for start + * so lets split this into before prefix, prefix, after + * prefix and let gmap_discard make some of these calls + * NOPs. + */ + gmap_discard(vcpu->arch.gmap, start, prefix); + if (start <= prefix) + gmap_discard(vcpu->arch.gmap, 0, PAGE_SIZE); + if (end > prefix + PAGE_SIZE) + gmap_discard(vcpu->arch.gmap, PAGE_SIZE, 2 * PAGE_SIZE); + gmap_discard(vcpu->arch.gmap, prefix + 2 * PAGE_SIZE, end); + } + return 0; +} + +static int __diag_page_ref_service(struct kvm_vcpu *vcpu) +{ + struct prs_parm { + u16 code; + u16 subcode; + u16 parm_len; + u16 parm_version; + u64 token_addr; + u64 select_mask; + u64 compare_mask; + u64 zarch; + }; + struct prs_parm parm; + int rc; + u16 rx = (vcpu->arch.sie_block->ipa & 0xf0) >> 4; + u16 ry = (vcpu->arch.sie_block->ipa & 0x0f); + + VCPU_EVENT(vcpu, 3, "diag page reference parameter block at 0x%llx", + vcpu->run->s.regs.gprs[rx]); + vcpu->stat.instruction_diagnose_258++; + if (vcpu->run->s.regs.gprs[rx] & 7) + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); + rc = read_guest(vcpu, vcpu->run->s.regs.gprs[rx], rx, &parm, sizeof(parm)); + if (rc) + return kvm_s390_inject_prog_cond(vcpu, rc); + if (parm.parm_version != 2 || parm.parm_len < 5 || parm.code != 0x258) + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); + + switch (parm.subcode) { + case 0: /* TOKEN */ + VCPU_EVENT(vcpu, 3, "pageref token addr 0x%llx " + "select mask 0x%llx compare mask 0x%llx", + parm.token_addr, parm.select_mask, parm.compare_mask); + if (vcpu->arch.pfault_token != KVM_S390_PFAULT_TOKEN_INVALID) { + /* + * If the pagefault handshake is already activated, + * the token must not be changed. We have to return + * decimal 8 instead, as mandated in SC24-6084. + */ + vcpu->run->s.regs.gprs[ry] = 8; + return 0; + } + + if ((parm.compare_mask & parm.select_mask) != parm.compare_mask || + parm.token_addr & 7 || parm.zarch != 0x8000000000000000ULL) + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); + + if (kvm_is_error_gpa(vcpu->kvm, parm.token_addr)) + return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); + + vcpu->arch.pfault_token = parm.token_addr; + vcpu->arch.pfault_select = parm.select_mask; + vcpu->arch.pfault_compare = parm.compare_mask; + vcpu->run->s.regs.gprs[ry] = 0; + rc = 0; + break; + case 1: /* + * CANCEL + * Specification allows to let already pending tokens survive + * the cancel, therefore to reduce code complexity, we assume + * all outstanding tokens are already pending. + */ + VCPU_EVENT(vcpu, 3, "pageref cancel addr 0x%llx", parm.token_addr); + if (parm.token_addr || parm.select_mask || + parm.compare_mask || parm.zarch) + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); + + vcpu->run->s.regs.gprs[ry] = 0; + /* + * If the pfault handling was not established or is already + * canceled SC24-6084 requests to return decimal 4. + */ + if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID) + vcpu->run->s.regs.gprs[ry] = 4; + else + vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID; + + rc = 0; + break; + default: + rc = -EOPNOTSUPP; + break; + } + + return rc; +} + +static int __diag_time_slice_end(struct kvm_vcpu *vcpu) +{ + VCPU_EVENT(vcpu, 5, "%s", "diag time slice end"); + vcpu->stat.instruction_diagnose_44++; + kvm_vcpu_on_spin(vcpu, true); + return 0; +} + +static int forward_cnt; +static unsigned long cur_slice; + +static int diag9c_forwarding_overrun(void) +{ + /* Reset the count on a new slice */ + if (time_after(jiffies, cur_slice)) { + cur_slice = jiffies; + forward_cnt = diag9c_forwarding_hz / HZ; + } + return forward_cnt-- <= 0 ? 1 : 0; +} + +static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu *tcpu; + int tcpu_cpu; + int tid; + + tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4]; + vcpu->stat.instruction_diagnose_9c++; + + /* yield to self */ + if (tid == vcpu->vcpu_id) + goto no_yield; + + /* yield to invalid */ + tcpu = kvm_get_vcpu_by_id(vcpu->kvm, tid); + if (!tcpu) + goto no_yield; + + /* target guest VCPU already running */ + tcpu_cpu = READ_ONCE(tcpu->cpu); + if (tcpu_cpu >= 0) { + if (!diag9c_forwarding_hz || diag9c_forwarding_overrun()) + goto no_yield; + + /* target host CPU already running */ + if (!vcpu_is_preempted(tcpu_cpu)) + goto no_yield; + smp_yield_cpu(tcpu_cpu); + VCPU_EVENT(vcpu, 5, + "diag time slice end directed to %d: yield forwarded", + tid); + vcpu->stat.diag_9c_forward++; + return 0; + } + + if (kvm_vcpu_yield_to(tcpu) <= 0) + goto no_yield; + + VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: done", tid); + return 0; +no_yield: + VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: ignored", tid); + vcpu->stat.diag_9c_ignored++; + return 0; +} + +static int __diag_ipl_functions(struct kvm_vcpu *vcpu) +{ + unsigned int reg = vcpu->arch.sie_block->ipa & 0xf; + unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff; + + VCPU_EVENT(vcpu, 3, "diag ipl functions, subcode %lx", subcode); + vcpu->stat.instruction_diagnose_308++; + switch (subcode) { + case 3: + vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR; + break; + case 4: + vcpu->run->s390_reset_flags = 0; + break; + default: + return -EOPNOTSUPP; + } + + /* + * no need to check the return value of vcpu_stop as it can only have + * an error for protvirt, but protvirt means user cpu state + */ + if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm)) + kvm_s390_vcpu_stop(vcpu); + vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM; + vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL; + vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT; + vcpu->run->exit_reason = KVM_EXIT_S390_RESET; + VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx", + vcpu->run->s390_reset_flags); + trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags); + return -EREMOTE; +} + +static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) +{ + int ret; + + vcpu->stat.instruction_diagnose_500++; + /* No virtio-ccw notification? Get out quickly. */ + if (!vcpu->kvm->arch.css_support || + (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY)) + return -EOPNOTSUPP; + + VCPU_EVENT(vcpu, 4, "diag 0x500 schid 0x%8.8x queue 0x%x cookie 0x%llx", + (u32) vcpu->run->s.regs.gprs[2], + (u32) vcpu->run->s.regs.gprs[3], + vcpu->run->s.regs.gprs[4]); + + /* + * The layout is as follows: + * - gpr 2 contains the subchannel id (passed as addr) + * - gpr 3 contains the virtqueue index (passed as datamatch) + * - gpr 4 contains the index on the bus (optionally) + */ + ret = kvm_io_bus_write_cookie(vcpu, KVM_VIRTIO_CCW_NOTIFY_BUS, + vcpu->run->s.regs.gprs[2] & 0xffffffff, + 8, &vcpu->run->s.regs.gprs[3], + vcpu->run->s.regs.gprs[4]); + + /* + * Return cookie in gpr 2, but don't overwrite the register if the + * diagnose will be handled by userspace. + */ + if (ret != -EOPNOTSUPP) + vcpu->run->s.regs.gprs[2] = ret; + /* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */ + return ret < 0 ? ret : 0; +} + +int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) +{ + int code = kvm_s390_get_base_disp_rs(vcpu, NULL) & 0xffff; + + if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) + return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); + + trace_kvm_s390_handle_diag(vcpu, code); + switch (code) { + case 0x10: + return diag_release_pages(vcpu); + case 0x44: + return __diag_time_slice_end(vcpu); + case 0x9c: + return __diag_time_slice_end_directed(vcpu); + case 0x258: + return __diag_page_ref_service(vcpu); + case 0x308: + return __diag_ipl_functions(vcpu); + case 0x500: + return __diag_virtio_hypercall(vcpu); + default: + vcpu->stat.instruction_diagnose_other++; + return -EOPNOTSUPP; + } +} |