target-arm/kvm32.c

   1 /*
   2  * ARM implementation of KVM hooks, 32 bit specific code.
   3  *
   4  * Copyright Christoffer Dall 2009-2010
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  *
   9  */
  10
  11 #include <stdio.h>
  12 #include <sys/types.h>
  13 #include <sys/ioctl.h>
  14 #include <sys/mman.h>
  15
  16 #include <linux/kvm.h>
  17
  18 #include "qemu-common.h"
  19 #include "qemu/timer.h"
  20 #include "sysemu/sysemu.h"
  21 #include "sysemu/kvm.h"
  22 #include "kvm_arm.h"
  23 #include "cpu.h"
  24 #include "internals.h"
  25 #include "hw/arm/arm.h"
  26
  27 static inline void set_feature(uint64_t *features, int feature)
  28 {
  29     *features |= 1ULL << feature;
  30 }
  31
  32 bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
  33 {
  34     /* Identify the feature bits corresponding to the host CPU, and
  35      * fill out the ARMHostCPUClass fields accordingly. To do this
  36      * we have to create a scratch VM, create a single CPU inside it,
  37      * and then query that CPU for the relevant ID registers.
  38      */
  39     int i, ret, fdarray[3];
  40     uint32_t midr, id_pfr0, id_isar0, mvfr1;
  41     uint64_t features = 0;
  42     /* Old kernels may not know about the PREFERRED_TARGET ioctl: however
  43      * we know these will only support creating one kind of guest CPU,
  44      * which is its preferred CPU type.
  45      */
  46     static const uint32_t cpus_to_try[] = {
  47         QEMU_KVM_ARM_TARGET_CORTEX_A15,
  48         QEMU_KVM_ARM_TARGET_NONE
  49     };
  50     struct kvm_vcpu_init init;
  51     struct kvm_one_reg idregs[] = {
  52         {
  53             .id = KVM_REG_ARM | KVM_REG_SIZE_U32
  54             | ENCODE_CP_REG(15, 0, 0, 0, 0, 0, 0),
  55             .addr = (uintptr_t)&midr,
  56         },
  57         {
  58             .id = KVM_REG_ARM | KVM_REG_SIZE_U32
  59             | ENCODE_CP_REG(15, 0, 0, 0, 1, 0, 0),
  60             .addr = (uintptr_t)&id_pfr0,
  61         },
  62         {
  63             .id = KVM_REG_ARM | KVM_REG_SIZE_U32
  64             | ENCODE_CP_REG(15, 0, 0, 0, 2, 0, 0),
  65             .addr = (uintptr_t)&id_isar0,
  66         },
  67         {
  68             .id = KVM_REG_ARM | KVM_REG_SIZE_U32
  69             | KVM_REG_ARM_VFP | KVM_REG_ARM_VFP_MVFR1,
  70             .addr = (uintptr_t)&mvfr1,
  71         },
  72     };
  73
  74     if (!kvm_arm_create_scratch_host_vcpu(cpus_to_try, fdarray, &init)) {
  75         return false;
  76     }
  77
  78     ahcc->target = init.target;
  79
  80     /* This is not strictly blessed by the device tree binding docs yet,
  81      * but in practice the kernel does not care about this string so
  82      * there is no point maintaining an KVM_ARM_TARGET_* -> string table.
  83      */
  84     ahcc->dtb_compatible = "arm,arm-v7";
  85
  86     for (i = 0; i < ARRAY_SIZE(idregs); i++) {
  87         ret = ioctl(fdarray[2], KVM_GET_ONE_REG, &idregs[i]);
  88         if (ret) {
  89             break;
  90         }
  91     }
  92
  93     kvm_arm_destroy_scratch_host_vcpu(fdarray);
  94
  95     if (ret) {
  96         return false;
  97     }
  98
  99     /* Now we've retrieved all the register information we can
 100      * set the feature bits based on the ID register fields.
 101      * We can assume any KVM supporting CPU is at least a v7
 102      * with VFPv3, LPAE and the generic timers; this in turn implies
 103      * most of the other feature bits, but a few must be tested.
 104      */
 105     set_feature(&features, ARM_FEATURE_V7);
 106     set_feature(&features, ARM_FEATURE_VFP3);
 107     set_feature(&features, ARM_FEATURE_LPAE);
 108     set_feature(&features, ARM_FEATURE_GENERIC_TIMER);
 109
 110     switch (extract32(id_isar0, 24, 4)) {
 111     case 1:
 112         set_feature(&features, ARM_FEATURE_THUMB_DIV);
 113         break;
 114     case 2:
 115         set_feature(&features, ARM_FEATURE_ARM_DIV);
 116         set_feature(&features, ARM_FEATURE_THUMB_DIV);
 117         break;
 118     default:
 119         break;
 120     }
 121
 122     if (extract32(id_pfr0, 12, 4) == 1) {
 123         set_feature(&features, ARM_FEATURE_THUMB2EE);
 124     }
 125     if (extract32(mvfr1, 20, 4) == 1) {
 126         set_feature(&features, ARM_FEATURE_VFP_FP16);
 127     }
 128     if (extract32(mvfr1, 12, 4) == 1) {
 129         set_feature(&features, ARM_FEATURE_NEON);
 130     }
 131     if (extract32(mvfr1, 28, 4) == 1) {
 132         /* FMAC support implies VFPv4 */
 133         set_feature(&features, ARM_FEATURE_VFP4);
 134     }
 135
 136     ahcc->features = features;
 137
 138     return true;
 139 }
 140
 141 bool kvm_arm_reg_syncs_via_cpreg_list(uint64_t regidx)
 142 {
 143     /* Return true if the regidx is a register we should synchronize
 144      * via the cpreg_tuples array (ie is not a core reg we sync by
 145      * hand in kvm_arch_get/put_registers())
 146      */
 147     switch (regidx & KVM_REG_ARM_COPROC_MASK) {
 148     case KVM_REG_ARM_CORE:
 149     case KVM_REG_ARM_VFP:
 150         return false;
 151     default:
 152         return true;
 153     }
 154 }
 155
 156 typedef struct CPRegStateLevel {
 157     uint64_t regidx;
 158     int level;
 159 } CPRegStateLevel;
 160
 161 /* All coprocessor registers not listed in the following table are assumed to
 162  * be of the level KVM_PUT_RUNTIME_STATE. If a register should be written less
 163  * often, you must add it to this table with a state of either
 164  * KVM_PUT_RESET_STATE or KVM_PUT_FULL_STATE.
 165  */
 166 static const CPRegStateLevel non_runtime_cpregs[] = {
 167     { KVM_REG_ARM_TIMER_CNT, KVM_PUT_FULL_STATE },
 168 };
 169
 170 int kvm_arm_cpreg_level(uint64_t regidx)
 171 {
 172     int i;
 173
 174     for (i = 0; i < ARRAY_SIZE(non_runtime_cpregs); i++) {
 175         const CPRegStateLevel *l = &non_runtime_cpregs[i];
 176         if (l->regidx == regidx) {
 177             return l->level;
 178         }
 179     }
 180
 181     return KVM_PUT_RUNTIME_STATE;
 182 }
 183
 184 #define ARM_MPIDR_HWID_BITMASK 0xFFFFFF
 185 #define ARM_CPU_ID_MPIDR       0, 0, 0, 5
 186
 187 int kvm_arch_init_vcpu(CPUState *cs)
 188 {
 189     int ret;
 190     uint64_t v;
 191     uint32_t mpidr;
 192     struct kvm_one_reg r;
 193     ARMCPU *cpu = ARM_CPU(cs);
 194
 195     if (cpu->kvm_target == QEMU_KVM_ARM_TARGET_NONE) {
 196         fprintf(stderr, "KVM is not supported for this guest CPU type\n");
 197         return -EINVAL;
 198     }
 199
 200     /* Determine init features for this CPU */
 201     memset(cpu->kvm_init_features, 0, sizeof(cpu->kvm_init_features));
 202     if (cpu->start_powered_off) {
 203         cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_POWER_OFF;
 204     }
 205     if (kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_PSCI_0_2)) {
 206         cpu->psci_version = 2;
 207         cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_PSCI_0_2;
 208     }
 209
 210     /* Do KVM_ARM_VCPU_INIT ioctl */
 211     ret = kvm_arm_vcpu_init(cs);
 212     if (ret) {
 213         return ret;
 214     }
 215
 216     /* Query the kernel to make sure it supports 32 VFP
 217      * registers: QEMU's "cortex-a15" CPU is always a
 218      * VFP-D32 core. The simplest way to do this is just
 219      * to attempt to read register d31.
 220      */
 221     r.id = KVM_REG_ARM | KVM_REG_SIZE_U64 | KVM_REG_ARM_VFP | 31;
 222     r.addr = (uintptr_t)(&v);
 223     ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);
 224     if (ret == -ENOENT) {
 225         return -EINVAL;
 226     }
 227
 228     /*
 229      * When KVM is in use, PSCI is emulated in-kernel and not by qemu.
 230      * Currently KVM has its own idea about MPIDR assignment, so we
 231      * override our defaults with what we get from KVM.
 232      */
 233     ret = kvm_get_one_reg(cs, ARM_CP15_REG32(ARM_CPU_ID_MPIDR), &mpidr);
 234     if (ret) {
 235         return ret;
 236     }
 237     cpu->mp_affinity = mpidr & ARM_MPIDR_HWID_BITMASK;
 238
 239     return kvm_arm_init_cpreg_list(cpu);
 240 }
 241
 242 typedef struct Reg {
 243     uint64_t id;
 244     int offset;
 245 } Reg;
 246
 247 #define COREREG(KERNELNAME, QEMUFIELD)                       \
 248     {                                                        \
 249         KVM_REG_ARM | KVM_REG_SIZE_U32 |                     \
 250         KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(KERNELNAME), \
 251         offsetof(CPUARMState, QEMUFIELD)                     \
 252     }
 253
 254 #define VFPSYSREG(R)                                       \
 255     {                                                      \
 256         KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP | \
 257         KVM_REG_ARM_VFP_##R,                               \
 258         offsetof(CPUARMState, vfp.xregs[ARM_VFP_##R])      \
 259     }
 260
 261 /* Like COREREG, but handle fields which are in a uint64_t in CPUARMState. */
 262 #define COREREG64(KERNELNAME, QEMUFIELD)                     \
 263     {                                                        \
 264         KVM_REG_ARM | KVM_REG_SIZE_U32 |                     \
 265         KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(KERNELNAME), \
 266         offsetoflow32(CPUARMState, QEMUFIELD)                \
 267     }
 268
 269 static const Reg regs[] = {
 270     /* R0_usr .. R14_usr */
 271     COREREG(usr_regs.uregs[0], regs[0]),
 272     COREREG(usr_regs.uregs[1], regs[1]),
 273     COREREG(usr_regs.uregs[2], regs[2]),
 274     COREREG(usr_regs.uregs[3], regs[3]),
 275     COREREG(usr_regs.uregs[4], regs[4]),
 276     COREREG(usr_regs.uregs[5], regs[5]),
 277     COREREG(usr_regs.uregs[6], regs[6]),
 278     COREREG(usr_regs.uregs[7], regs[7]),
 279     COREREG(usr_regs.uregs[8], usr_regs[0]),
 280     COREREG(usr_regs.uregs[9], usr_regs[1]),
 281     COREREG(usr_regs.uregs[10], usr_regs[2]),
 282     COREREG(usr_regs.uregs[11], usr_regs[3]),
 283     COREREG(usr_regs.uregs[12], usr_regs[4]),
 284     COREREG(usr_regs.uregs[13], banked_r13[0]),
 285     COREREG(usr_regs.uregs[14], banked_r14[0]),
 286     /* R13, R14, SPSR for SVC, ABT, UND, IRQ banks */
 287     COREREG(svc_regs[0], banked_r13[1]),
 288     COREREG(svc_regs[1], banked_r14[1]),
 289     COREREG64(svc_regs[2], banked_spsr[1]),
 290     COREREG(abt_regs[0], banked_r13[2]),
 291     COREREG(abt_regs[1], banked_r14[2]),
 292     COREREG64(abt_regs[2], banked_spsr[2]),
 293     COREREG(und_regs[0], banked_r13[3]),
 294     COREREG(und_regs[1], banked_r14[3]),
 295     COREREG64(und_regs[2], banked_spsr[3]),
 296     COREREG(irq_regs[0], banked_r13[4]),
 297     COREREG(irq_regs[1], banked_r14[4]),
 298     COREREG64(irq_regs[2], banked_spsr[4]),
 299     /* R8_fiq .. R14_fiq and SPSR_fiq */
 300     COREREG(fiq_regs[0], fiq_regs[0]),
 301     COREREG(fiq_regs[1], fiq_regs[1]),
 302     COREREG(fiq_regs[2], fiq_regs[2]),
 303     COREREG(fiq_regs[3], fiq_regs[3]),
 304     COREREG(fiq_regs[4], fiq_regs[4]),
 305     COREREG(fiq_regs[5], banked_r13[5]),
 306     COREREG(fiq_regs[6], banked_r14[5]),
 307     COREREG64(fiq_regs[7], banked_spsr[5]),
 308     /* R15 */
 309     COREREG(usr_regs.uregs[15], regs[15]),
 310     /* VFP system registers */
 311     VFPSYSREG(FPSID),
 312     VFPSYSREG(MVFR1),
 313     VFPSYSREG(MVFR0),
 314     VFPSYSREG(FPEXC),
 315     VFPSYSREG(FPINST),
 316     VFPSYSREG(FPINST2),
 317 };
 318
 319 int kvm_arch_put_registers(CPUState *cs, int level)
 320 {
 321     ARMCPU *cpu = ARM_CPU(cs);
 322     CPUARMState *env = &cpu->env;
 323     struct kvm_one_reg r;
 324     int mode, bn;
 325     int ret, i;
 326     uint32_t cpsr, fpscr;
 327
 328     /* Make sure the banked regs are properly set */
 329     mode = env->uncached_cpsr & CPSR_M;
 330     bn = bank_number(mode);
 331     if (mode == ARM_CPU_MODE_FIQ) {
 332         memcpy(env->fiq_regs, env->regs + 8, 5 * sizeof(uint32_t));
 333     } else {
 334         memcpy(env->usr_regs, env->regs + 8, 5 * sizeof(uint32_t));
 335     }
 336     env->banked_r13[bn] = env->regs[13];
 337     env->banked_r14[bn] = env->regs[14];
 338     env->banked_spsr[bn] = env->spsr;
 339
 340     /* Now we can safely copy stuff down to the kernel */
 341     for (i = 0; i < ARRAY_SIZE(regs); i++) {
 342         r.id = regs[i].id;
 343         r.addr = (uintptr_t)(env) + regs[i].offset;
 344         ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &r);
 345         if (ret) {
 346             return ret;
 347         }
 348     }
 349
 350     /* Special cases which aren't a single CPUARMState field */
 351     cpsr = cpsr_read(env);
 352     r.id = KVM_REG_ARM | KVM_REG_SIZE_U32 |
 353         KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(usr_regs.ARM_cpsr);
 354     r.addr = (uintptr_t)(&cpsr);
 355     ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &r);
 356     if (ret) {
 357         return ret;
 358     }
 359
 360     /* VFP registers */
 361     r.id = KVM_REG_ARM | KVM_REG_SIZE_U64 | KVM_REG_ARM_VFP;
 362     for (i = 0; i < 32; i++) {
 363         r.addr = (uintptr_t)(&env->vfp.regs[i]);
 364         ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &r);
 365         if (ret) {
 366             return ret;
 367         }
 368         r.id++;
 369     }
 370
 371     r.id = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP |
 372         KVM_REG_ARM_VFP_FPSCR;
 373     fpscr = vfp_get_fpscr(env);
 374     r.addr = (uintptr_t)&fpscr;
 375     ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &r);
 376     if (ret) {
 377         return ret;
 378     }
 379
 380     /* Note that we do not call write_cpustate_to_list()
 381      * here, so we are only writing the tuple list back to
 382      * KVM. This is safe because nothing can change the
 383      * CPUARMState cp15 fields (in particular gdb accesses cannot)
 384      * and so there are no changes to sync. In fact syncing would
 385      * be wrong at this point: for a constant register where TCG and
 386      * KVM disagree about its value, the preceding write_list_to_cpustate()
 387      * would not have had any effect on the CPUARMState value (since the
 388      * register is read-only), and a write_cpustate_to_list() here would
 389      * then try to write the TCG value back into KVM -- this would either
 390      * fail or incorrectly change the value the guest sees.
 391      *
 392      * If we ever want to allow the user to modify cp15 registers via
 393      * the gdb stub, we would need to be more clever here (for instance
 394      * tracking the set of registers kvm_arch_get_registers() successfully
 395      * managed to update the CPUARMState with, and only allowing those
 396      * to be written back up into the kernel).
 397      */
 398     if (!write_list_to_kvmstate(cpu, level)) {
 399         return EINVAL;
 400     }
 401
 402     kvm_arm_sync_mpstate_to_kvm(cpu);
 403
 404     return ret;
 405 }
 406
 407 int kvm_arch_get_registers(CPUState *cs)
 408 {
 409     ARMCPU *cpu = ARM_CPU(cs);
 410     CPUARMState *env = &cpu->env;
 411     struct kvm_one_reg r;
 412     int mode, bn;
 413     int ret, i;
 414     uint32_t cpsr, fpscr;
 415
 416     for (i = 0; i < ARRAY_SIZE(regs); i++) {
 417         r.id = regs[i].id;
 418         r.addr = (uintptr_t)(env) + regs[i].offset;
 419         ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);
 420         if (ret) {
 421             return ret;
 422         }
 423     }
 424
 425     /* Special cases which aren't a single CPUARMState field */
 426     r.id = KVM_REG_ARM | KVM_REG_SIZE_U32 |
 427         KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(usr_regs.ARM_cpsr);
 428     r.addr = (uintptr_t)(&cpsr);
 429     ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);
 430     if (ret) {
 431         return ret;
 432     }
 433     cpsr_write(env, cpsr, 0xffffffff);
 434
 435     /* Make sure the current mode regs are properly set */
 436     mode = env->uncached_cpsr & CPSR_M;
 437     bn = bank_number(mode);
 438     if (mode == ARM_CPU_MODE_FIQ) {
 439         memcpy(env->regs + 8, env->fiq_regs, 5 * sizeof(uint32_t));
 440     } else {
 441         memcpy(env->regs + 8, env->usr_regs, 5 * sizeof(uint32_t));
 442     }
 443     env->regs[13] = env->banked_r13[bn];
 444     env->regs[14] = env->banked_r14[bn];
 445     env->spsr = env->banked_spsr[bn];
 446
 447     /* VFP registers */
 448     r.id = KVM_REG_ARM | KVM_REG_SIZE_U64 | KVM_REG_ARM_VFP;
 449     for (i = 0; i < 32; i++) {
 450         r.addr = (uintptr_t)(&env->vfp.regs[i]);
 451         ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);
 452         if (ret) {
 453             return ret;
 454         }
 455         r.id++;
 456     }
 457
 458     r.id = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP |
 459         KVM_REG_ARM_VFP_FPSCR;
 460     r.addr = (uintptr_t)&fpscr;
 461     ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &r);
 462     if (ret) {
 463         return ret;
 464     }
 465     vfp_set_fpscr(env, fpscr);
 466
 467     if (!write_kvmstate_to_list(cpu)) {
 468         return EINVAL;
 469     }
 470     /* Note that it's OK to have registers which aren't in CPUState,
 471      * so we can ignore a failure return here.
 472      */
 473     write_list_to_cpustate(cpu);
 474
 475     kvm_arm_sync_mpstate_to_qemu(cpu);
 476
 477     return 0;
 478 }