kernel/arch/s390/kvm/diag.c

   1 /*
   2  * handling diagnose instructions
   3  *
   4  * Copyright IBM Corp. 2008, 2011
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License (version 2 only)
   8  * as published by the Free Software Foundation.
   9  *
  10  *    Author(s): Carsten Otte <cotte@de.ibm.com>
  11  *               Christian Borntraeger <borntraeger@de.ibm.com>
  12  */
  13
  14 #include <linux/kvm.h>
  15 #include <linux/kvm_host.h>
  16 #include <asm/pgalloc.h>
  17 #include <asm/virtio-ccw.h>
  18 #include "kvm-s390.h"
  19 #include "trace.h"
  20 #include "trace-s390.h"
  21 #include "gaccess.h"
  22
  23 static int diag_release_pages(struct kvm_vcpu *vcpu)
  24 {
  25         unsigned long start, end;
  26         unsigned long prefix  = kvm_s390_get_prefix(vcpu);
  27
  28         start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
  29         end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;
  30
  31         if (start & ~PAGE_MASK || end & ~PAGE_MASK || start >= end
  32             || start < 2 * PAGE_SIZE)
  33                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  34
  35         VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
  36         vcpu->stat.diagnose_10++;
  37
  38         /*
  39          * We checked for start >= end above, so lets check for the
  40          * fast path (no prefix swap page involved)
  41          */
  42         if (end <= prefix || start >= prefix + 2 * PAGE_SIZE) {
  43                 gmap_discard(vcpu->arch.gmap, start, end);
  44         } else {
  45                 /*
  46                  * This is slow path.  gmap_discard will check for start
  47                  * so lets split this into before prefix, prefix, after
  48                  * prefix and let gmap_discard make some of these calls
  49                  * NOPs.
  50                  */
  51                 gmap_discard(vcpu->arch.gmap, start, prefix);
  52                 if (start <= prefix)
  53                         gmap_discard(vcpu->arch.gmap, 0, 4096);
  54                 if (end > prefix + 4096)
  55                         gmap_discard(vcpu->arch.gmap, 4096, 8192);
  56                 gmap_discard(vcpu->arch.gmap, prefix + 2 * PAGE_SIZE, end);
  57         }
  58         return 0;
  59 }
  60
  61 static int __diag_page_ref_service(struct kvm_vcpu *vcpu)
  62 {
  63         struct prs_parm {
  64                 u16 code;
  65                 u16 subcode;
  66                 u16 parm_len;
  67                 u16 parm_version;
  68                 u64 token_addr;
  69                 u64 select_mask;
  70                 u64 compare_mask;
  71                 u64 zarch;
  72         };
  73         struct prs_parm parm;
  74         int rc;
  75         u16 rx = (vcpu->arch.sie_block->ipa & 0xf0) >> 4;
  76         u16 ry = (vcpu->arch.sie_block->ipa & 0x0f);
  77
  78         if (vcpu->run->s.regs.gprs[rx] & 7)
  79                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  80         rc = read_guest(vcpu, vcpu->run->s.regs.gprs[rx], rx, &parm, sizeof(parm));
  81         if (rc)
  82                 return kvm_s390_inject_prog_cond(vcpu, rc);
  83         if (parm.parm_version != 2 || parm.parm_len < 5 || parm.code != 0x258)
  84                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  85
  86         switch (parm.subcode) {
  87         case 0: /* TOKEN */
  88                 if (vcpu->arch.pfault_token != KVM_S390_PFAULT_TOKEN_INVALID) {
  89                         /*
  90                          * If the pagefault handshake is already activated,
  91                          * the token must not be changed.  We have to return
  92                          * decimal 8 instead, as mandated in SC24-6084.
  93                          */
  94                         vcpu->run->s.regs.gprs[ry] = 8;
  95                         return 0;
  96                 }
  97
  98                 if ((parm.compare_mask & parm.select_mask) != parm.compare_mask ||
  99                     parm.token_addr & 7 || parm.zarch != 0x8000000000000000ULL)
 100                         return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 101
 102                 if (kvm_is_error_gpa(vcpu->kvm, parm.token_addr))
 103                         return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 104
 105                 vcpu->arch.pfault_token = parm.token_addr;
 106                 vcpu->arch.pfault_select = parm.select_mask;
 107                 vcpu->arch.pfault_compare = parm.compare_mask;
 108                 vcpu->run->s.regs.gprs[ry] = 0;
 109                 rc = 0;
 110                 break;
 111         case 1: /*
 112                  * CANCEL
 113                  * Specification allows to let already pending tokens survive
 114                  * the cancel, therefore to reduce code complexity, we assume
 115                  * all outstanding tokens are already pending.
 116                  */
 117                 if (parm.token_addr || parm.select_mask ||
 118                     parm.compare_mask || parm.zarch)
 119                         return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 120
 121                 vcpu->run->s.regs.gprs[ry] = 0;
 122                 /*
 123                  * If the pfault handling was not established or is already
 124                  * canceled SC24-6084 requests to return decimal 4.
 125                  */
 126                 if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID)
 127                         vcpu->run->s.regs.gprs[ry] = 4;
 128                 else
 129                         vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
 130
 131                 rc = 0;
 132                 break;
 133         default:
 134                 rc = -EOPNOTSUPP;
 135                 break;
 136         }
 137
 138         return rc;
 139 }
 140
 141 static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
 142 {
 143         VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
 144         vcpu->stat.diagnose_44++;
 145         kvm_vcpu_on_spin(vcpu);
 146         return 0;
 147 }
 148
 149 static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
 150 {
 151         struct kvm *kvm = vcpu->kvm;
 152         struct kvm_vcpu *tcpu;
 153         int tid;
 154         int i;
 155
 156         tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
 157         vcpu->stat.diagnose_9c++;
 158         VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);
 159
 160         if (tid == vcpu->vcpu_id)
 161                 return 0;
 162
 163         kvm_for_each_vcpu(i, tcpu, kvm)
 164                 if (tcpu->vcpu_id == tid) {
 165                         kvm_vcpu_yield_to(tcpu);
 166                         break;
 167                 }
 168
 169         return 0;
 170 }
 171
 172 static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
 173 {
 174         unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;
 175         unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff;
 176
 177         VCPU_EVENT(vcpu, 5, "diag ipl functions, subcode %lx", subcode);
 178         switch (subcode) {
 179         case 3:
 180                 vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
 181                 break;
 182         case 4:
 183                 vcpu->run->s390_reset_flags = 0;
 184                 break;
 185         default:
 186                 return -EOPNOTSUPP;
 187         }
 188
 189         if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
 190                 kvm_s390_vcpu_stop(vcpu);
 191         vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;
 192         vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;
 193         vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;
 194         vcpu->run->exit_reason = KVM_EXIT_S390_RESET;
 195         VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx",
 196           vcpu->run->s390_reset_flags);
 197         trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags);
 198         return -EREMOTE;
 199 }
 200
 201 static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
 202 {
 203         int ret;
 204
 205         /* No virtio-ccw notification? Get out quickly. */
 206         if (!vcpu->kvm->arch.css_support ||
 207             (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
 208                 return -EOPNOTSUPP;
 209
 210         /*
 211          * The layout is as follows:
 212          * - gpr 2 contains the subchannel id (passed as addr)
 213          * - gpr 3 contains the virtqueue index (passed as datamatch)
 214          * - gpr 4 contains the index on the bus (optionally)
 215          */
 216         ret = kvm_io_bus_write_cookie(vcpu, KVM_VIRTIO_CCW_NOTIFY_BUS,
 217                                       vcpu->run->s.regs.gprs[2] & 0xffffffff,
 218                                       8, &vcpu->run->s.regs.gprs[3],
 219                                       vcpu->run->s.regs.gprs[4]);
 220
 221         /*
 222          * Return cookie in gpr 2, but don't overwrite the register if the
 223          * diagnose will be handled by userspace.
 224          */
 225         if (ret != -EOPNOTSUPP)
 226                 vcpu->run->s.regs.gprs[2] = ret;
 227         /* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */
 228         return ret < 0 ? ret : 0;
 229 }
 230
 231 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
 232 {
 233         int code = kvm_s390_get_base_disp_rs(vcpu, NULL) & 0xffff;
 234
 235         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 236                 return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
 237
 238         trace_kvm_s390_handle_diag(vcpu, code);
 239         switch (code) {
 240         case 0x10:
 241                 return diag_release_pages(vcpu);
 242         case 0x44:
 243                 return __diag_time_slice_end(vcpu);
 244         case 0x9c:
 245                 return __diag_time_slice_end_directed(vcpu);
 246         case 0x258:
 247                 return __diag_page_ref_service(vcpu);
 248         case 0x308:
 249                 return __diag_ipl_functions(vcpu);
 250         case 0x500:
 251                 return __diag_virtio_hypercall(vcpu);
 252         default:
 253                 return -EOPNOTSUPP;
 254         }
 255 }