arch/s390/kvm/priv.c

   1 /*
   2  * handling privileged instructions
   3  *
   4  * Copyright IBM Corp. 2008
   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/gfp.h>
  16 #include <linux/errno.h>
  17 #include <asm/current.h>
  18 #include <asm/debug.h>
  19 #include <asm/ebcdic.h>
  20 #include <asm/sysinfo.h>
  21 #include "gaccess.h"
  22 #include "kvm-s390.h"
  23
  24 static int handle_set_prefix(struct kvm_vcpu *vcpu)
  25 {
  26         int base2 = vcpu->arch.sie_block->ipb >> 28;
  27         int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
  28         u64 operand2;
  29         u32 address = 0;
  30         u8 tmp;
  31
  32         vcpu->stat.instruction_spx++;
  33
  34         operand2 = disp2;
  35         if (base2)
  36                 operand2 += vcpu->run->s.regs.gprs[base2];
  37
  38         /* must be word boundary */
  39         if (operand2 & 3) {
  40                 kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  41                 goto out;
  42         }
  43
  44         /* get the value */
  45         if (get_guest_u32(vcpu, operand2, &address)) {
  46                 kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
  47                 goto out;
  48         }
  49
  50         address = address & 0x7fffe000u;
  51
  52         /* make sure that the new value is valid memory */
  53         if (copy_from_guest_absolute(vcpu, &tmp, address, 1) ||
  54            (copy_from_guest_absolute(vcpu, &tmp, address + PAGE_SIZE, 1))) {
  55                 kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
  56                 goto out;
  57         }
  58
  59         kvm_s390_set_prefix(vcpu, address);
  60
  61         VCPU_EVENT(vcpu, 5, "setting prefix to %x", address);
  62 out:
  63         return 0;
  64 }
  65
  66 static int handle_store_prefix(struct kvm_vcpu *vcpu)
  67 {
  68         int base2 = vcpu->arch.sie_block->ipb >> 28;
  69         int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
  70         u64 operand2;
  71         u32 address;
  72
  73         vcpu->stat.instruction_stpx++;
  74         operand2 = disp2;
  75         if (base2)
  76                 operand2 += vcpu->run->s.regs.gprs[base2];
  77
  78         /* must be word boundary */
  79         if (operand2 & 3) {
  80                 kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  81                 goto out;
  82         }
  83
  84         address = vcpu->arch.sie_block->prefix;
  85         address = address & 0x7fffe000u;
  86
  87         /* get the value */
  88         if (put_guest_u32(vcpu, operand2, address)) {
  89                 kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
  90                 goto out;
  91         }
  92
  93         VCPU_EVENT(vcpu, 5, "storing prefix to %x", address);
  94 out:
  95         return 0;
  96 }
  97
  98 static int handle_store_cpu_address(struct kvm_vcpu *vcpu)
  99 {
 100         int base2 = vcpu->arch.sie_block->ipb >> 28;
 101         int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
 102         u64 useraddr;
 103         int rc;
 104
 105         vcpu->stat.instruction_stap++;
 106         useraddr = disp2;
 107         if (base2)
 108                 useraddr += vcpu->run->s.regs.gprs[base2];
 109
 110         if (useraddr & 1) {
 111                 kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 112                 goto out;
 113         }
 114
 115         rc = put_guest_u16(vcpu, useraddr, vcpu->vcpu_id);
 116         if (rc == -EFAULT) {
 117                 kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 118                 goto out;
 119         }
 120
 121         VCPU_EVENT(vcpu, 5, "storing cpu address to %llx", useraddr);
 122 out:
 123         return 0;
 124 }
 125
 126 static int handle_skey(struct kvm_vcpu *vcpu)
 127 {
 128         vcpu->stat.instruction_storage_key++;
 129         vcpu->arch.sie_block->gpsw.addr -= 4;
 130         VCPU_EVENT(vcpu, 4, "%s", "retrying storage key operation");
 131         return 0;
 132 }
 133
 134 static int handle_stsch(struct kvm_vcpu *vcpu)
 135 {
 136         vcpu->stat.instruction_stsch++;
 137         VCPU_EVENT(vcpu, 4, "%s", "store subchannel - CC3");
 138         /* condition code 3 */
 139         vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 140         vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
 141         return 0;
 142 }
 143
 144 static int handle_chsc(struct kvm_vcpu *vcpu)
 145 {
 146         vcpu->stat.instruction_chsc++;
 147         VCPU_EVENT(vcpu, 4, "%s", "channel subsystem call - CC3");
 148         /* condition code 3 */
 149         vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 150         vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
 151         return 0;
 152 }
 153
 154 static int handle_stfl(struct kvm_vcpu *vcpu)
 155 {
 156         unsigned int facility_list;
 157         int rc;
 158
 159         vcpu->stat.instruction_stfl++;
 160         /* only pass the facility bits, which we can handle */
 161         facility_list = S390_lowcore.stfl_fac_list & 0xff00fff3;
 162
 163         rc = copy_to_guest(vcpu, offsetof(struct _lowcore, stfl_fac_list),
 164                            &facility_list, sizeof(facility_list));
 165         if (rc == -EFAULT)
 166                 kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 167         else
 168                 VCPU_EVENT(vcpu, 5, "store facility list value %x",
 169                            facility_list);
 170         return 0;
 171 }
 172
 173 static int handle_stidp(struct kvm_vcpu *vcpu)
 174 {
 175         int base2 = vcpu->arch.sie_block->ipb >> 28;
 176         int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
 177         u64 operand2;
 178         int rc;
 179
 180         vcpu->stat.instruction_stidp++;
 181         operand2 = disp2;
 182         if (base2)
 183                 operand2 += vcpu->run->s.regs.gprs[base2];
 184
 185         if (operand2 & 7) {
 186                 kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 187                 goto out;
 188         }
 189
 190         rc = put_guest_u64(vcpu, operand2, vcpu->arch.stidp_data);
 191         if (rc == -EFAULT) {
 192                 kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 193                 goto out;
 194         }
 195
 196         VCPU_EVENT(vcpu, 5, "%s", "store cpu id");
 197 out:
 198         return 0;
 199 }
 200
 201 static void handle_stsi_3_2_2(struct kvm_vcpu *vcpu, struct sysinfo_3_2_2 *mem)
 202 {
 203         struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
 204         int cpus = 0;
 205         int n;
 206
 207         spin_lock(&fi->lock);
 208         for (n = 0; n < KVM_MAX_VCPUS; n++)
 209                 if (fi->local_int[n])
 210                         cpus++;
 211         spin_unlock(&fi->lock);
 212
 213         /* deal with other level 3 hypervisors */
 214         if (stsi(mem, 3, 2, 2) == -ENOSYS)
 215                 mem->count = 0;
 216         if (mem->count < 8)
 217                 mem->count++;
 218         for (n = mem->count - 1; n > 0 ; n--)
 219                 memcpy(&mem->vm[n], &mem->vm[n - 1], sizeof(mem->vm[0]));
 220
 221         mem->vm[0].cpus_total = cpus;
 222         mem->vm[0].cpus_configured = cpus;
 223         mem->vm[0].cpus_standby = 0;
 224         mem->vm[0].cpus_reserved = 0;
 225         mem->vm[0].caf = 1000;
 226         memcpy(mem->vm[0].name, "KVMguest", 8);
 227         ASCEBC(mem->vm[0].name, 8);
 228         memcpy(mem->vm[0].cpi, "KVM/Linux       ", 16);
 229         ASCEBC(mem->vm[0].cpi, 16);
 230 }
 231
 232 static int handle_stsi(struct kvm_vcpu *vcpu)
 233 {
 234         int fc = (vcpu->run->s.regs.gprs[0] & 0xf0000000) >> 28;
 235         int sel1 = vcpu->run->s.regs.gprs[0] & 0xff;
 236         int sel2 = vcpu->run->s.regs.gprs[1] & 0xffff;
 237         int base2 = vcpu->arch.sie_block->ipb >> 28;
 238         int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
 239         u64 operand2;
 240         unsigned long mem;
 241
 242         vcpu->stat.instruction_stsi++;
 243         VCPU_EVENT(vcpu, 4, "stsi: fc: %x sel1: %x sel2: %x", fc, sel1, sel2);
 244
 245         operand2 = disp2;
 246         if (base2)
 247                 operand2 += vcpu->run->s.regs.gprs[base2];
 248
 249         if (operand2 & 0xfff && fc > 0)
 250                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 251
 252         switch (fc) {
 253         case 0:
 254                 vcpu->run->s.regs.gprs[0] = 3 << 28;
 255                 vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 256                 return 0;
 257         case 1: /* same handling for 1 and 2 */
 258         case 2:
 259                 mem = get_zeroed_page(GFP_KERNEL);
 260                 if (!mem)
 261                         goto out_fail;
 262                 if (stsi((void *) mem, fc, sel1, sel2) == -ENOSYS)
 263                         goto out_mem;
 264                 break;
 265         case 3:
 266                 if (sel1 != 2 || sel2 != 2)
 267                         goto out_fail;
 268                 mem = get_zeroed_page(GFP_KERNEL);
 269                 if (!mem)
 270                         goto out_fail;
 271                 handle_stsi_3_2_2(vcpu, (void *) mem);
 272                 break;
 273         default:
 274                 goto out_fail;
 275         }
 276
 277         if (copy_to_guest_absolute(vcpu, operand2, (void *) mem, PAGE_SIZE)) {
 278                 kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 279                 goto out_mem;
 280         }
 281         free_page(mem);
 282         vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 283         vcpu->run->s.regs.gprs[0] = 0;
 284         return 0;
 285 out_mem:
 286         free_page(mem);
 287 out_fail:
 288         /* condition code 3 */
 289         vcpu->arch.sie_block->gpsw.mask |= 3ul << 44;
 290         return 0;
 291 }
 292
 293 static intercept_handler_t priv_handlers[256] = {
 294         [0x02] = handle_stidp,
 295         [0x10] = handle_set_prefix,
 296         [0x11] = handle_store_prefix,
 297         [0x12] = handle_store_cpu_address,
 298         [0x29] = handle_skey,
 299         [0x2a] = handle_skey,
 300         [0x2b] = handle_skey,
 301         [0x34] = handle_stsch,
 302         [0x5f] = handle_chsc,
 303         [0x7d] = handle_stsi,
 304         [0xb1] = handle_stfl,
 305 };
 306
 307 int kvm_s390_handle_b2(struct kvm_vcpu *vcpu)
 308 {
 309         intercept_handler_t handler;
 310
 311         /*
 312          * a lot of B2 instructions are priviledged. We first check for
 313          * the privileged ones, that we can handle in the kernel. If the
 314          * kernel can handle this instruction, we check for the problem
 315          * state bit and (a) handle the instruction or (b) send a code 2
 316          * program check.
 317          * Anything else goes to userspace.*/
 318         handler = priv_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
 319         if (handler) {
 320                 if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 321                         return kvm_s390_inject_program_int(vcpu,
 322                                                    PGM_PRIVILEGED_OPERATION);
 323                 else
 324                         return handler(vcpu);
 325         }
 326         return -EOPNOTSUPP;
 327 }
 328
 329 static int handle_tprot(struct kvm_vcpu *vcpu)
 330 {
 331         int base1 = (vcpu->arch.sie_block->ipb & 0xf0000000) >> 28;
 332         int disp1 = (vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16;
 333         int base2 = (vcpu->arch.sie_block->ipb & 0xf000) >> 12;
 334         int disp2 = vcpu->arch.sie_block->ipb & 0x0fff;
 335         u64 address1 = disp1 + base1 ? vcpu->run->s.regs.gprs[base1] : 0;
 336         u64 address2 = disp2 + base2 ? vcpu->run->s.regs.gprs[base2] : 0;
 337         struct vm_area_struct *vma;
 338         unsigned long user_address;
 339
 340         vcpu->stat.instruction_tprot++;
 341
 342         /* we only handle the Linux memory detection case:
 343          * access key == 0
 344          * guest DAT == off
 345          * everything else goes to userspace. */
 346         if (address2 & 0xf0)
 347                 return -EOPNOTSUPP;
 348         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
 349                 return -EOPNOTSUPP;
 350
 351
 352         /* we must resolve the address without holding the mmap semaphore.
 353          * This is ok since the userspace hypervisor is not supposed to change
 354          * the mapping while the guest queries the memory. Otherwise the guest
 355          * might crash or get wrong info anyway. */
 356         user_address = (unsigned long) __guestaddr_to_user(vcpu, address1);
 357
 358         down_read(&current->mm->mmap_sem);
 359         vma = find_vma(current->mm, user_address);
 360         if (!vma) {
 361                 up_read(&current->mm->mmap_sem);
 362                 return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 363         }
 364
 365         vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
 366         if (!(vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_READ))
 367                 vcpu->arch.sie_block->gpsw.mask |= (1ul << 44);
 368         if (!(vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_READ))
 369                 vcpu->arch.sie_block->gpsw.mask |= (2ul << 44);
 370
 371         up_read(&current->mm->mmap_sem);
 372         return 0;
 373 }
 374
 375 int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)
 376 {
 377         /* For e5xx... instructions we only handle TPROT */
 378         if ((vcpu->arch.sie_block->ipa & 0x00ff) == 0x01)
 379                 return handle_tprot(vcpu);
 380         return -EOPNOTSUPP;
 381 }
 382
 383 static int handle_sckpf(struct kvm_vcpu *vcpu)
 384 {
 385         u32 value;
 386
 387         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 388                 return kvm_s390_inject_program_int(vcpu,
 389                                                    PGM_PRIVILEGED_OPERATION);
 390
 391         if (vcpu->run->s.regs.gprs[0] & 0x00000000ffff0000)
 392                 return kvm_s390_inject_program_int(vcpu,
 393                                                    PGM_SPECIFICATION);
 394
 395         value = vcpu->run->s.regs.gprs[0] & 0x000000000000ffff;
 396         vcpu->arch.sie_block->todpr = value;
 397
 398         return 0;
 399 }
 400
 401 static intercept_handler_t x01_handlers[256] = {
 402         [0x07] = handle_sckpf,
 403 };
 404
 405 int kvm_s390_handle_01(struct kvm_vcpu *vcpu)
 406 {
 407         intercept_handler_t handler;
 408
 409         handler = x01_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
 410         if (handler)
 411                 return handler(vcpu);
 412         return -EOPNOTSUPP;
 413 }