xemu/target/s390x/misc_helper.c

/*
 *  S/390 misc helper routines
 *
 *  Copyright (c) 2009 Ulrich Hecht
 *  Copyright (c) 2009 Alexander Graf
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

#include "qemu/osdep.h"
#include "qemu/main-loop.h"
#include "cpu.h"
#include "exec/memory.h"
#include "qemu/host-utils.h"
#include "exec/helper-proto.h"
#include "sysemu/kvm.h"
#include "qemu/timer.h"
#include "qemu/main-loop.h"
#include "exec/address-spaces.h"
#ifdef CONFIG_KVM
#include <linux/kvm.h>
#endif
#include "exec/exec-all.h"
#include "exec/cpu_ldst.h"

#if !defined(CONFIG_USER_ONLY)
#include "hw/watchdog/wdt_diag288.h"
#include "sysemu/cpus.h"
#include "sysemu/sysemu.h"
#include "hw/s390x/ebcdic.h"
#include "hw/s390x/ipl.h"
#endif

/* #define DEBUG_HELPER */
#ifdef DEBUG_HELPER
#define HELPER_LOG(x...) qemu_log(x)
#else
#define HELPER_LOG(x...)
#endif

/* Raise an exception dynamically from a helper function.  */
void QEMU_NORETURN runtime_exception(CPUS390XState *env, int excp,
                                     uintptr_t retaddr)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));
    int t;

    cs->exception_index = EXCP_PGM;
    env->int_pgm_code = excp;

    /* Use the (ultimate) callers address to find the insn that trapped.  */
    cpu_restore_state(cs, retaddr);

    /* Advance past the insn.  */
    t = cpu_ldub_code(env, env->psw.addr);
    env->int_pgm_ilen = t = get_ilen(t);
    env->psw.addr += t;

    cpu_loop_exit(cs);
}

/* Raise an exception statically from a TB.  */
void HELPER(exception)(CPUS390XState *env, uint32_t excp)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));

    HELPER_LOG("%s: exception %d\n", __func__, excp);
    cs->exception_index = excp;
    cpu_loop_exit(cs);
}

#ifndef CONFIG_USER_ONLY

void program_interrupt(CPUS390XState *env, uint32_t code, int ilen)
{
    S390CPU *cpu = s390_env_get_cpu(env);

    qemu_log_mask(CPU_LOG_INT, "program interrupt at %#" PRIx64 "\n",
                  env->psw.addr);

    if (kvm_enabled()) {
#ifdef CONFIG_KVM
        struct kvm_s390_irq irq = {
            .type = KVM_S390_PROGRAM_INT,
            .u.pgm.code = code,
        };

        kvm_s390_vcpu_interrupt(cpu, &irq);
#endif
    } else {
        CPUState *cs = CPU(cpu);

        env->int_pgm_code = code;
        env->int_pgm_ilen = ilen;
        cs->exception_index = EXCP_PGM;
        cpu_loop_exit(cs);
    }
}

/* SCLP service call */
uint32_t HELPER(servc)(CPUS390XState *env, uint64_t r1, uint64_t r2)
{
    qemu_mutex_lock_iothread();
    int r = sclp_service_call(env, r1, r2);
    if (r < 0) {
        program_interrupt(env, -r, 4);
        r = 0;
    }
    qemu_mutex_unlock_iothread();
    return r;
}

#ifndef CONFIG_USER_ONLY
static int modified_clear_reset(S390CPU *cpu)
{
    S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);
    CPUState *t;

    pause_all_vcpus();
    cpu_synchronize_all_states();
    CPU_FOREACH(t) {
        run_on_cpu(t, s390_do_cpu_full_reset, RUN_ON_CPU_NULL);
    }
    s390_cmma_reset();
    subsystem_reset();
    s390_crypto_reset();
    scc->load_normal(CPU(cpu));
    cpu_synchronize_all_post_reset();
    resume_all_vcpus();
    return 0;
}

static int load_normal_reset(S390CPU *cpu)
{
    S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);
    CPUState *t;

    pause_all_vcpus();
    cpu_synchronize_all_states();
    CPU_FOREACH(t) {
        run_on_cpu(t, s390_do_cpu_reset, RUN_ON_CPU_NULL);
    }
    s390_cmma_reset();
    subsystem_reset();
    scc->initial_cpu_reset(CPU(cpu));
    scc->load_normal(CPU(cpu));
    cpu_synchronize_all_post_reset();
    resume_all_vcpus();
    return 0;
}

int handle_diag_288(CPUS390XState *env, uint64_t r1, uint64_t r3)
{
    uint64_t func = env->regs[r1];
    uint64_t timeout = env->regs[r1 + 1];
    uint64_t action = env->regs[r3];
    Object *obj;
    DIAG288State *diag288;
    DIAG288Class *diag288_class;

    if (r1 % 2 || action != 0) {
        return -1;
    }

    /* Timeout must be more than 15 seconds except for timer deletion */
    if (func != WDT_DIAG288_CANCEL && timeout < 15) {
        return -1;
    }

    obj = object_resolve_path_type("", TYPE_WDT_DIAG288, NULL);
    if (!obj) {
        return -1;
    }

    diag288 = DIAG288(obj);
    diag288_class = DIAG288_GET_CLASS(diag288);
    return diag288_class->handle_timer(diag288, func, timeout);
}

#define DIAG_308_RC_OK              0x0001
#define DIAG_308_RC_NO_CONF         0x0102
#define DIAG_308_RC_INVALID         0x0402

void handle_diag_308(CPUS390XState *env, uint64_t r1, uint64_t r3)
{
    uint64_t addr =  env->regs[r1];
    uint64_t subcode = env->regs[r3];
    IplParameterBlock *iplb;

    if (env->psw.mask & PSW_MASK_PSTATE) {
        program_interrupt(env, PGM_PRIVILEGED, ILEN_LATER_INC);
        return;
    }

    if ((subcode & ~0x0ffffULL) || (subcode > 6)) {
        program_interrupt(env, PGM_SPECIFICATION, ILEN_LATER_INC);
        return;
    }

    switch (subcode) {
    case 0:
        modified_clear_reset(s390_env_get_cpu(env));
        if (tcg_enabled()) {
            cpu_loop_exit(CPU(s390_env_get_cpu(env)));
        }
        break;
    case 1:
        load_normal_reset(s390_env_get_cpu(env));
        if (tcg_enabled()) {
            cpu_loop_exit(CPU(s390_env_get_cpu(env)));
        }
        break;
    case 3:
        s390_reipl_request();
        if (tcg_enabled()) {
            cpu_loop_exit(CPU(s390_env_get_cpu(env)));
        }
        break;
    case 5:
        if ((r1 & 1) || (addr & 0x0fffULL)) {
            program_interrupt(env, PGM_SPECIFICATION, ILEN_LATER_INC);
            return;
        }
        if (!address_space_access_valid(&address_space_memory, addr,
                                        sizeof(IplParameterBlock), false)) {
            program_interrupt(env, PGM_ADDRESSING, ILEN_LATER_INC);
            return;
        }
        iplb = g_malloc0(sizeof(IplParameterBlock));
        cpu_physical_memory_read(addr, iplb, sizeof(iplb->len));
        if (!iplb_valid_len(iplb)) {
            env->regs[r1 + 1] = DIAG_308_RC_INVALID;
            goto out;
        }

        cpu_physical_memory_read(addr, iplb, be32_to_cpu(iplb->len));

        if (!iplb_valid_ccw(iplb) && !iplb_valid_fcp(iplb)) {
            env->regs[r1 + 1] = DIAG_308_RC_INVALID;
            goto out;
        }

        s390_ipl_update_diag308(iplb);
        env->regs[r1 + 1] = DIAG_308_RC_OK;
out:
        g_free(iplb);
        return;
    case 6:
        if ((r1 & 1) || (addr & 0x0fffULL)) {
            program_interrupt(env, PGM_SPECIFICATION, ILEN_LATER_INC);
            return;
        }
        if (!address_space_access_valid(&address_space_memory, addr,
                                        sizeof(IplParameterBlock), true)) {
            program_interrupt(env, PGM_ADDRESSING, ILEN_LATER_INC);
            return;
        }
        iplb = s390_ipl_get_iplb();
        if (iplb) {
            cpu_physical_memory_write(addr, iplb, be32_to_cpu(iplb->len));
            env->regs[r1 + 1] = DIAG_308_RC_OK;
        } else {
            env->regs[r1 + 1] = DIAG_308_RC_NO_CONF;
        }
        return;
    default:
        hw_error("Unhandled diag308 subcode %" PRIx64, subcode);
        break;
    }
}
#endif

void HELPER(diag)(CPUS390XState *env, uint32_t r1, uint32_t r3, uint32_t num)
{
    uint64_t r;

    switch (num) {
    case 0x500:
        /* KVM hypercall */
        qemu_mutex_lock_iothread();
        r = s390_virtio_hypercall(env);
        qemu_mutex_unlock_iothread();
        break;
    case 0x44:
        /* yield */
        r = 0;
        break;
    case 0x308:
        /* ipl */
        handle_diag_308(env, r1, r3);
        r = 0;
        break;
    default:
        r = -1;
        break;
    }

    if (r) {
        program_interrupt(env, PGM_OPERATION, ILEN_LATER_INC);
    }
}

/* Set Prefix */
void HELPER(spx)(CPUS390XState *env, uint64_t a1)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));
    uint32_t prefix = a1 & 0x7fffe000;

    env->psa = prefix;
    HELPER_LOG("prefix: %#x\n", prefix);
    tlb_flush_page(cs, 0);
    tlb_flush_page(cs, TARGET_PAGE_SIZE);
}

/* Store Clock */
uint64_t HELPER(stck)(CPUS390XState *env)
{
    uint64_t time;

    time = env->tod_offset +
        time2tod(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - env->tod_basetime);

    return time;
}

/* Set Clock Comparator */
void HELPER(sckc)(CPUS390XState *env, uint64_t time)
{
    if (time == -1ULL) {
        return;
    }

    env->ckc = time;

    /* difference between origins */
    time -= env->tod_offset;

    /* nanoseconds */
    time = tod2time(time);

    timer_mod(env->tod_timer, env->tod_basetime + time);
}

/* Store Clock Comparator */
uint64_t HELPER(stckc)(CPUS390XState *env)
{
    return env->ckc;
}

/* Set CPU Timer */
void HELPER(spt)(CPUS390XState *env, uint64_t time)
{
    if (time == -1ULL) {
        return;
    }

    /* nanoseconds */
    time = tod2time(time);

    env->cputm = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + time;

    timer_mod(env->cpu_timer, env->cputm);
}

/* Store CPU Timer */
uint64_t HELPER(stpt)(CPUS390XState *env)
{
    return time2tod(env->cputm - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
}

/* Store System Information */
uint32_t HELPER(stsi)(CPUS390XState *env, uint64_t a0,
                      uint64_t r0, uint64_t r1)
{
    int cc = 0;
    int sel1, sel2;

    if ((r0 & STSI_LEVEL_MASK) <= STSI_LEVEL_3 &&
        ((r0 & STSI_R0_RESERVED_MASK) || (r1 & STSI_R1_RESERVED_MASK))) {
        /* valid function code, invalid reserved bits */
        program_interrupt(env, PGM_SPECIFICATION, 2);
    }

    sel1 = r0 & STSI_R0_SEL1_MASK;
    sel2 = r1 & STSI_R1_SEL2_MASK;

    /* XXX: spec exception if sysib is not 4k-aligned */

    switch (r0 & STSI_LEVEL_MASK) {
    case STSI_LEVEL_1:
        if ((sel1 == 1) && (sel2 == 1)) {
            /* Basic Machine Configuration */
            struct sysib_111 sysib;

            memset(&sysib, 0, sizeof(sysib));
            ebcdic_put(sysib.manuf, "QEMU            ", 16);
            /* same as machine type number in STORE CPU ID */
            ebcdic_put(sysib.type, "QEMU", 4);
            /* same as model number in STORE CPU ID */
            ebcdic_put(sysib.model, "QEMU            ", 16);
            ebcdic_put(sysib.sequence, "QEMU            ", 16);
            ebcdic_put(sysib.plant, "QEMU", 4);
            cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
        } else if ((sel1 == 2) && (sel2 == 1)) {
            /* Basic Machine CPU */
            struct sysib_121 sysib;

            memset(&sysib, 0, sizeof(sysib));
            /* XXX make different for different CPUs? */
            ebcdic_put(sysib.sequence, "QEMUQEMUQEMUQEMU", 16);
            ebcdic_put(sysib.plant, "QEMU", 4);
            stw_p(&sysib.cpu_addr, env->cpu_num);
            cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
        } else if ((sel1 == 2) && (sel2 == 2)) {
            /* Basic Machine CPUs */
            struct sysib_122 sysib;

            memset(&sysib, 0, sizeof(sysib));
            stl_p(&sysib.capability, 0x443afc29);
            /* XXX change when SMP comes */
            stw_p(&sysib.total_cpus, 1);
            stw_p(&sysib.active_cpus, 1);
            stw_p(&sysib.standby_cpus, 0);
            stw_p(&sysib.reserved_cpus, 0);
            cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
        } else {
            cc = 3;
        }
        break;
    case STSI_LEVEL_2:
        {
            if ((sel1 == 2) && (sel2 == 1)) {
                /* LPAR CPU */
                struct sysib_221 sysib;

                memset(&sysib, 0, sizeof(sysib));
                /* XXX make different for different CPUs? */
                ebcdic_put(sysib.sequence, "QEMUQEMUQEMUQEMU", 16);
                ebcdic_put(sysib.plant, "QEMU", 4);
                stw_p(&sysib.cpu_addr, env->cpu_num);
                stw_p(&sysib.cpu_id, 0);
                cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
            } else if ((sel1 == 2) && (sel2 == 2)) {
                /* LPAR CPUs */
                struct sysib_222 sysib;

                memset(&sysib, 0, sizeof(sysib));
                stw_p(&sysib.lpar_num, 0);
                sysib.lcpuc = 0;
                /* XXX change when SMP comes */
                stw_p(&sysib.total_cpus, 1);
                stw_p(&sysib.conf_cpus, 1);
                stw_p(&sysib.standby_cpus, 0);
                stw_p(&sysib.reserved_cpus, 0);
                ebcdic_put(sysib.name, "QEMU    ", 8);
                stl_p(&sysib.caf, 1000);
                stw_p(&sysib.dedicated_cpus, 0);
                stw_p(&sysib.shared_cpus, 0);
                cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
            } else {
                cc = 3;
            }
            break;
        }
    case STSI_LEVEL_3:
        {
            if ((sel1 == 2) && (sel2 == 2)) {
                /* VM CPUs */
                struct sysib_322 sysib;

                memset(&sysib, 0, sizeof(sysib));
                sysib.count = 1;
                /* XXX change when SMP comes */
                stw_p(&sysib.vm[0].total_cpus, 1);
                stw_p(&sysib.vm[0].conf_cpus, 1);
                stw_p(&sysib.vm[0].standby_cpus, 0);
                stw_p(&sysib.vm[0].reserved_cpus, 0);
                ebcdic_put(sysib.vm[0].name, "KVMguest", 8);
                stl_p(&sysib.vm[0].caf, 1000);
                ebcdic_put(sysib.vm[0].cpi, "KVM/Linux       ", 16);
                cpu_physical_memory_write(a0, &sysib, sizeof(sysib));
            } else {
                cc = 3;
            }
            break;
        }
    case STSI_LEVEL_CURRENT:
        env->regs[0] = STSI_LEVEL_3;
        break;
    default:
        cc = 3;
        break;
    }

    return cc;
}

uint32_t HELPER(sigp)(CPUS390XState *env, uint64_t order_code, uint32_t r1,
                      uint64_t cpu_addr)
{
    int cc = SIGP_CC_ORDER_CODE_ACCEPTED;

    HELPER_LOG("%s: %016" PRIx64 " %08x %016" PRIx64 "\n",
               __func__, order_code, r1, cpu_addr);

    /* Remember: Use "R1 or R1 + 1, whichever is the odd-numbered register"
       as parameter (input). Status (output) is always R1. */

    switch (order_code & SIGP_ORDER_MASK) {
    case SIGP_SET_ARCH:
        /* switch arch */
        break;
    case SIGP_SENSE:
        /* enumerate CPU status */
        if (cpu_addr) {
            /* XXX implement when SMP comes */
            return 3;
        }
        env->regs[r1] &= 0xffffffff00000000ULL;
        cc = 1;
        break;
#if !defined(CONFIG_USER_ONLY)
    case SIGP_RESTART:
        qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
        cpu_loop_exit(CPU(s390_env_get_cpu(env)));
        break;
    case SIGP_STOP:
        qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
        cpu_loop_exit(CPU(s390_env_get_cpu(env)));
        break;
#endif
    default:
        /* unknown sigp */
        fprintf(stderr, "XXX unknown sigp: 0x%" PRIx64 "\n", order_code);
        cc = SIGP_CC_NOT_OPERATIONAL;
    }

    return cc;
}
#endif

#ifndef CONFIG_USER_ONLY
void HELPER(xsch)(CPUS390XState *env, uint64_t r1)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_xsch(cpu, r1);
    qemu_mutex_unlock_iothread();
}

void HELPER(csch)(CPUS390XState *env, uint64_t r1)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_csch(cpu, r1);
    qemu_mutex_unlock_iothread();
}

void HELPER(hsch)(CPUS390XState *env, uint64_t r1)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_hsch(cpu, r1);
    qemu_mutex_unlock_iothread();
}

void HELPER(msch)(CPUS390XState *env, uint64_t r1, uint64_t inst)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_msch(cpu, r1, inst >> 16);
    qemu_mutex_unlock_iothread();
}

void HELPER(rchp)(CPUS390XState *env, uint64_t r1)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_rchp(cpu, r1);
    qemu_mutex_unlock_iothread();
}

void HELPER(rsch)(CPUS390XState *env, uint64_t r1)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_rsch(cpu, r1);
    qemu_mutex_unlock_iothread();
}

void HELPER(ssch)(CPUS390XState *env, uint64_t r1, uint64_t inst)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_ssch(cpu, r1, inst >> 16);
    qemu_mutex_unlock_iothread();
}

void HELPER(stsch)(CPUS390XState *env, uint64_t r1, uint64_t inst)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_stsch(cpu, r1, inst >> 16);
    qemu_mutex_unlock_iothread();
}

void HELPER(tsch)(CPUS390XState *env, uint64_t r1, uint64_t inst)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_tsch(cpu, r1, inst >> 16);
    qemu_mutex_unlock_iothread();
}

void HELPER(chsc)(CPUS390XState *env, uint64_t inst)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    qemu_mutex_lock_iothread();
    ioinst_handle_chsc(cpu, inst >> 16);
    qemu_mutex_unlock_iothread();
}
#endif

#ifndef CONFIG_USER_ONLY
void HELPER(per_check_exception)(CPUS390XState *env)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));

    if (env->per_perc_atmid) {
        env->int_pgm_code = PGM_PER;
        env->int_pgm_ilen = get_ilen(cpu_ldub_code(env, env->per_address));

        cs->exception_index = EXCP_PGM;
        cpu_loop_exit(cs);
    }
}

void HELPER(per_branch)(CPUS390XState *env, uint64_t from, uint64_t to)
{
    if ((env->cregs[9] & PER_CR9_EVENT_BRANCH)) {
        if (!(env->cregs[9] & PER_CR9_CONTROL_BRANCH_ADDRESS)
            || get_per_in_range(env, to)) {
            env->per_address = from;
            env->per_perc_atmid = PER_CODE_EVENT_BRANCH | get_per_atmid(env);
        }
    }
}

void HELPER(per_ifetch)(CPUS390XState *env, uint64_t addr)
{
    if ((env->cregs[9] & PER_CR9_EVENT_IFETCH) && get_per_in_range(env, addr)) {
        env->per_address = addr;
        env->per_perc_atmid = PER_CODE_EVENT_IFETCH | get_per_atmid(env);

        /* If the instruction has to be nullified, trigger the
           exception immediately. */
        if (env->cregs[9] & PER_CR9_EVENT_NULLIFICATION) {
            CPUState *cs = CPU(s390_env_get_cpu(env));

            env->int_pgm_code = PGM_PER;
            env->int_pgm_ilen = get_ilen(cpu_ldub_code(env, addr));

            cs->exception_index = EXCP_PGM;
            cpu_loop_exit(cs);
        }
    }
}
#endif

/* The maximum bit defined at the moment is 129.  */
#define MAX_STFL_WORDS  3

/* Canonicalize the current cpu's features into the 64-bit words required
   by STFLE.  Return the index-1 of the max word that is non-zero.  */
static unsigned do_stfle(CPUS390XState *env, uint64_t words[MAX_STFL_WORDS])
{
    S390CPU *cpu = s390_env_get_cpu(env);
    const unsigned long *features = cpu->model->features;
    unsigned max_bit = 0;
    S390Feat feat;

    memset(words, 0, sizeof(uint64_t) * MAX_STFL_WORDS);

    if (test_bit(S390_FEAT_ZARCH, features)) {
        /* z/Architecture is always active if around */
        words[0] = 1ull << (63 - 2);
    }

    for (feat = find_first_bit(features, S390_FEAT_MAX);
         feat < S390_FEAT_MAX;
         feat = find_next_bit(features, S390_FEAT_MAX, feat + 1)) {
        const S390FeatDef *def = s390_feat_def(feat);
        if (def->type == S390_FEAT_TYPE_STFL) {
            unsigned bit = def->bit;
            if (bit > max_bit) {
                max_bit = bit;
            }
            assert(bit / 64 < MAX_STFL_WORDS);
            words[bit / 64] |= 1ULL << (63 - bit % 64);
        }
    }

    return max_bit / 64;
}

void HELPER(stfl)(CPUS390XState *env)
{
    uint64_t words[MAX_STFL_WORDS];

    do_stfle(env, words);
    cpu_stl_data(env, 200, words[0] >> 32);
}

uint32_t HELPER(stfle)(CPUS390XState *env, uint64_t addr)
{
    uint64_t words[MAX_STFL_WORDS];
    unsigned count_m1 = env->regs[0] & 0xff;
    unsigned max_m1 = do_stfle(env, words);
    unsigned i;

    for (i = 0; i <= count_m1; ++i) {
        cpu_stq_data(env, addr + 8 * i, words[i]);
    }

    env->regs[0] = deposit64(env->regs[0], 0, 8, max_m1);
    return (count_m1 >= max_m1 ? 0 : 3);
}