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/gmap.h>
  18 #include <asm/virtio-ccw.h>
  19 #include "kvm-s390.h"
  20 #include "trace.h"
  21 #include "trace-s390.h"
  22 #include "gaccess.h"
  23
  24 static int diag_release_pages(struct kvm_vcpu *vcpu)
  25 {
  26         unsigned long start, end;
  27         unsigned long prefix  = kvm_s390_get_prefix(vcpu);
  28
  29         start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
  30         end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;
  31         vcpu->stat.diagnose_10++;
  32
  33         if (start & ~PAGE_MASK || end & ~PAGE_MASK || start >= end
  34             || start < 2 * PAGE_SIZE)
  35                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  36
  37         VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
  38
  39         /*
  40          * We checked for start >= end above, so lets check for the
  41          * fast path (no prefix swap page involved)
  42          */
  43         if (end <= prefix || start >= prefix + 2 * PAGE_SIZE) {
  44                 gmap_discard(vcpu->arch.gmap, start, end);
  45         } else {
  46                 /*
  47                  * This is slow path.  gmap_discard will check for start
  48                  * so lets split this into before prefix, prefix, after
  49                  * prefix and let gmap_discard make some of these calls
  50                  * NOPs.
  51                  */
  52                 gmap_discard(vcpu->arch.gmap, start, prefix);
  53                 if (start <= prefix)
  54                         gmap_discard(vcpu->arch.gmap, 0, 4096);
  55                 if (end > prefix + 4096)
  56                         gmap_discard(vcpu->arch.gmap, 4096, 8192);
  57                 gmap_discard(vcpu->arch.gmap, prefix + 2 * PAGE_SIZE, end);
  58         }
  59         return 0;
  60 }
  61
  62 static int __diag_page_ref_service(struct kvm_vcpu *vcpu)
  63 {
  64         struct prs_parm {
  65                 u16 code;
  66                 u16 subcode;
  67                 u16 parm_len;
  68                 u16 parm_version;
  69                 u64 token_addr;
  70                 u64 select_mask;
  71                 u64 compare_mask;
  72                 u64 zarch;
  73         };
  74         struct prs_parm parm;
  75         int rc;
  76         u16 rx = (vcpu->arch.sie_block->ipa & 0xf0) >> 4;
  77         u16 ry = (vcpu->arch.sie_block->ipa & 0x0f);
  78
  79         VCPU_EVENT(vcpu, 3, "diag page reference parameter block at 0x%llx",
  80                    vcpu->run->s.regs.gprs[rx]);
  81         vcpu->stat.diagnose_258++;
  82         if (vcpu->run->s.regs.gprs[rx] & 7)
  83                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  84         rc = read_guest(vcpu, vcpu->run->s.regs.gprs[rx], rx, &parm, sizeof(parm));
  85         if (rc)
  86                 return kvm_s390_inject_prog_cond(vcpu, rc);
  87         if (parm.parm_version != 2 || parm.parm_len < 5 || parm.code != 0x258)
  88                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  89
  90         switch (parm.subcode) {
  91         case 0: /* TOKEN */
  92                 VCPU_EVENT(vcpu, 3, "pageref token addr 0x%llx "
  93                            "select mask 0x%llx compare mask 0x%llx",
  94                            parm.token_addr, parm.select_mask, parm.compare_mask);
  95                 if (vcpu->arch.pfault_token != KVM_S390_PFAULT_TOKEN_INVALID) {
  96                         /*
  97                          * If the pagefault handshake is already activated,
  98                          * the token must not be changed.  We have to return
  99                          * decimal 8 instead, as mandated in SC24-6084.
 100                          */
 101                         vcpu->run->s.regs.gprs[ry] = 8;
 102                         return 0;
 103                 }
 104
 105                 if ((parm.compare_mask & parm.select_mask) != parm.compare_mask ||
 106                     parm.token_addr & 7 || parm.zarch != 0x8000000000000000ULL)
 107                         return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 108
 109                 if (kvm_is_error_gpa(vcpu->kvm, parm.token_addr))
 110                         return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 111
 112                 vcpu->arch.pfault_token = parm.token_addr;
 113                 vcpu->arch.pfault_select = parm.select_mask;
 114                 vcpu->arch.pfault_compare = parm.compare_mask;
 115                 vcpu->run->s.regs.gprs[ry] = 0;
 116                 rc = 0;
 117                 break;
 118         case 1: /*
 119                  * CANCEL
 120                  * Specification allows to let already pending tokens survive
 121                  * the cancel, therefore to reduce code complexity, we assume
 122                  * all outstanding tokens are already pending.
 123                  */
 124                 VCPU_EVENT(vcpu, 3, "pageref cancel addr 0x%llx", parm.token_addr);
 125                 if (parm.token_addr || parm.select_mask ||
 126                     parm.compare_mask || parm.zarch)
 127                         return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 128
 129                 vcpu->run->s.regs.gprs[ry] = 0;
 130                 /*
 131                  * If the pfault handling was not established or is already
 132                  * canceled SC24-6084 requests to return decimal 4.
 133                  */
 134                 if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID)
 135                         vcpu->run->s.regs.gprs[ry] = 4;
 136                 else
 137                         vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
 138
 139                 rc = 0;
 140                 break;
 141         default:
 142                 rc = -EOPNOTSUPP;
 143                 break;
 144         }
 145
 146         return rc;
 147 }
 148
 149 static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
 150 {
 151         VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
 152         vcpu->stat.diagnose_44++;
 153         kvm_vcpu_on_spin(vcpu);
 154         return 0;
 155 }
 156
 157 static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
 158 {
 159         struct kvm_vcpu *tcpu;
 160         int tid;
 161
 162         tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
 163         vcpu->stat.diagnose_9c++;
 164         VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);
 165
 166         if (tid == vcpu->vcpu_id)
 167                 return 0;
 168
 169         tcpu = kvm_get_vcpu_by_id(vcpu->kvm, tid);
 170         if (tcpu)
 171                 kvm_vcpu_yield_to(tcpu);
 172         return 0;
 173 }
 174
 175 static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
 176 {
 177         unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;
 178         unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff;
 179
 180         VCPU_EVENT(vcpu, 3, "diag ipl functions, subcode %lx", subcode);
 181         vcpu->stat.diagnose_308++;
 182         switch (subcode) {
 183         case 3:
 184                 vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
 185                 break;
 186         case 4:
 187                 vcpu->run->s390_reset_flags = 0;
 188                 break;
 189         default:
 190                 return -EOPNOTSUPP;
 191         }
 192
 193         if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
 194                 kvm_s390_vcpu_stop(vcpu);
 195         vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;
 196         vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;
 197         vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;
 198         vcpu->run->exit_reason = KVM_EXIT_S390_RESET;
 199         VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx",
 200           vcpu->run->s390_reset_flags);
 201         trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags);
 202         return -EREMOTE;
 203 }
 204
 205 static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
 206 {
 207         int ret;
 208
 209         vcpu->stat.diagnose_500++;
 210         /* No virtio-ccw notification? Get out quickly. */
 211         if (!vcpu->kvm->arch.css_support ||
 212             (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
 213                 return -EOPNOTSUPP;
 214
 215         VCPU_EVENT(vcpu, 4, "diag 0x500 schid 0x%8.8x queue 0x%x cookie 0x%llx",
 216                             (u32) vcpu->run->s.regs.gprs[2],
 217                             (u32) vcpu->run->s.regs.gprs[3],
 218                             vcpu->run->s.regs.gprs[4]);
 219
 220         /*
 221          * The layout is as follows:
 222          * - gpr 2 contains the subchannel id (passed as addr)
 223          * - gpr 3 contains the virtqueue index (passed as datamatch)
 224          * - gpr 4 contains the index on the bus (optionally)
 225          */
 226         ret = kvm_io_bus_write_cookie(vcpu, KVM_VIRTIO_CCW_NOTIFY_BUS,
 227                                       vcpu->run->s.regs.gprs[2] & 0xffffffff,
 228                                       8, &vcpu->run->s.regs.gprs[3],
 229                                       vcpu->run->s.regs.gprs[4]);
 230
 231         /*
 232          * Return cookie in gpr 2, but don't overwrite the register if the
 233          * diagnose will be handled by userspace.
 234          */
 235         if (ret != -EOPNOTSUPP)
 236                 vcpu->run->s.regs.gprs[2] = ret;
 237         /* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */
 238         return ret < 0 ? ret : 0;
 239 }
 240
 241 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
 242 {
 243         int code = kvm_s390_get_base_disp_rs(vcpu, NULL) & 0xffff;
 244
 245         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 246                 return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
 247
 248         trace_kvm_s390_handle_diag(vcpu, code);
 249         switch (code) {
 250         case 0x10:
 251                 return diag_release_pages(vcpu);
 252         case 0x44:
 253                 return __diag_time_slice_end(vcpu);
 254         case 0x9c:
 255                 return __diag_time_slice_end_directed(vcpu);
 256         case 0x258:
 257                 return __diag_page_ref_service(vcpu);
 258         case 0x308:
 259                 return __diag_ipl_functions(vcpu);
 260         case 0x500:
 261                 return __diag_virtio_hypercall(vcpu);
 262         default:
 263                 return -EOPNOTSUPP;
 264         }
 265 }