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