qemu/target-s390x/kvm.c

/*
 * QEMU S390x KVM implementation
 *
 * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
 * Copyright IBM Corp. 2012
 *
 * 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.
 *
 * Contributions after 2012-10-29 are licensed under the terms of the
 * GNU GPL, version 2 or (at your option) any later version.
 *
 * 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 <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mman.h>

#include <linux/kvm.h>
#include <asm/ptrace.h>

#include "qemu-common.h"
#include "qemu/timer.h"
#include "sysemu/sysemu.h"
#include "sysemu/kvm.h"
#include "hw/hw.h"
#include "cpu.h"
#include "sysemu/device_tree.h"
#include "qapi/qmp/qjson.h"
#include "monitor/monitor.h"
#include "exec/gdbstub.h"
#include "trace.h"
#include "qapi-event.h"

/* #define DEBUG_KVM */

#ifdef DEBUG_KVM
#define DPRINTF(fmt, ...) \
    do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) \
    do { } while (0)
#endif

#define IPA0_DIAG                       0x8300
#define IPA0_SIGP                       0xae00
#define IPA0_B2                         0xb200
#define IPA0_B9                         0xb900
#define IPA0_EB                         0xeb00

#define PRIV_B2_SCLP_CALL               0x20
#define PRIV_B2_CSCH                    0x30
#define PRIV_B2_HSCH                    0x31
#define PRIV_B2_MSCH                    0x32
#define PRIV_B2_SSCH                    0x33
#define PRIV_B2_STSCH                   0x34
#define PRIV_B2_TSCH                    0x35
#define PRIV_B2_TPI                     0x36
#define PRIV_B2_SAL                     0x37
#define PRIV_B2_RSCH                    0x38
#define PRIV_B2_STCRW                   0x39
#define PRIV_B2_STCPS                   0x3a
#define PRIV_B2_RCHP                    0x3b
#define PRIV_B2_SCHM                    0x3c
#define PRIV_B2_CHSC                    0x5f
#define PRIV_B2_SIGA                    0x74
#define PRIV_B2_XSCH                    0x76

#define PRIV_EB_SQBS                    0x8a

#define PRIV_B9_EQBS                    0x9c

#define DIAG_IPL                        0x308
#define DIAG_KVM_HYPERCALL              0x500
#define DIAG_KVM_BREAKPOINT             0x501

#define ICPT_INSTRUCTION                0x04
#define ICPT_PROGRAM                    0x08
#define ICPT_EXT_INT                    0x14
#define ICPT_WAITPSW                    0x1c
#define ICPT_SOFT_INTERCEPT             0x24
#define ICPT_CPU_STOP                   0x28
#define ICPT_IO                         0x40

static CPUWatchpoint hw_watchpoint;
/*
 * We don't use a list because this structure is also used to transmit the
 * hardware breakpoints to the kernel.
 */
static struct kvm_hw_breakpoint *hw_breakpoints;
static int nb_hw_breakpoints;

const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
    KVM_CAP_LAST_INFO
};

static int cap_sync_regs;
static int cap_async_pf;

static void *legacy_s390_alloc(size_t size);

static int kvm_s390_check_clear_cmma(KVMState *s)
{
    struct kvm_device_attr attr = {
        .group = KVM_S390_VM_MEM_CTRL,
        .attr = KVM_S390_VM_MEM_CLR_CMMA,
    };

    return kvm_vm_ioctl(s, KVM_HAS_DEVICE_ATTR, &attr);
}

static int kvm_s390_check_enable_cmma(KVMState *s)
{
    struct kvm_device_attr attr = {
        .group = KVM_S390_VM_MEM_CTRL,
        .attr = KVM_S390_VM_MEM_ENABLE_CMMA,
    };

    return kvm_vm_ioctl(s, KVM_HAS_DEVICE_ATTR, &attr);
}

void kvm_s390_clear_cmma_callback(void *opaque)
{
    int rc;
    KVMState *s = opaque;
    struct kvm_device_attr attr = {
        .group = KVM_S390_VM_MEM_CTRL,
        .attr = KVM_S390_VM_MEM_CLR_CMMA,
    };

    rc = kvm_vm_ioctl(s, KVM_SET_DEVICE_ATTR, &attr);
    trace_kvm_clear_cmma(rc);
}

static void kvm_s390_enable_cmma(KVMState *s)
{
    int rc;
    struct kvm_device_attr attr = {
        .group = KVM_S390_VM_MEM_CTRL,
        .attr = KVM_S390_VM_MEM_ENABLE_CMMA,
    };

    if (kvm_s390_check_enable_cmma(s) || kvm_s390_check_clear_cmma(s)) {
        return;
    }

    rc = kvm_vm_ioctl(s, KVM_SET_DEVICE_ATTR, &attr);
    if (!rc) {
        qemu_register_reset(kvm_s390_clear_cmma_callback, s);
    }
    trace_kvm_enable_cmma(rc);
}

int kvm_arch_init(KVMState *s)
{
    cap_sync_regs = kvm_check_extension(s, KVM_CAP_SYNC_REGS);
    cap_async_pf = kvm_check_extension(s, KVM_CAP_ASYNC_PF);

    if (kvm_check_extension(s, KVM_CAP_VM_ATTRIBUTES)) {
        kvm_s390_enable_cmma(s);
    }

    if (!kvm_check_extension(s, KVM_CAP_S390_GMAP)
        || !kvm_check_extension(s, KVM_CAP_S390_COW)) {
        phys_mem_set_alloc(legacy_s390_alloc);
    }
    return 0;
}

unsigned long kvm_arch_vcpu_id(CPUState *cpu)
{
    return cpu->cpu_index;
}

int kvm_arch_init_vcpu(CPUState *cs)
{
    S390CPU *cpu = S390_CPU(cs);
    kvm_s390_set_cpu_state(cpu, cpu->env.cpu_state);
    return 0;
}

void kvm_s390_reset_vcpu(S390CPU *cpu)
{
    CPUState *cs = CPU(cpu);

    /* The initial reset call is needed here to reset in-kernel
     * vcpu data that we can't access directly from QEMU
     * (i.e. with older kernels which don't support sync_regs/ONE_REG).
     * Before this ioctl cpu_synchronize_state() is called in common kvm
     * code (kvm-all) */
    if (kvm_vcpu_ioctl(cs, KVM_S390_INITIAL_RESET, NULL)) {
        error_report("Initial CPU reset failed on CPU %i\n", cs->cpu_index);
    }
}

int kvm_arch_put_registers(CPUState *cs, int level)
{
    S390CPU *cpu = S390_CPU(cs);
    CPUS390XState *env = &cpu->env;
    struct kvm_sregs sregs;
    struct kvm_regs regs;
    struct kvm_fpu fpu = {};
    int r;
    int i;

    /* always save the PSW  and the GPRS*/
    cs->kvm_run->psw_addr = env->psw.addr;
    cs->kvm_run->psw_mask = env->psw.mask;

    if (cap_sync_regs && cs->kvm_run->kvm_valid_regs & KVM_SYNC_GPRS) {
        for (i = 0; i < 16; i++) {
            cs->kvm_run->s.regs.gprs[i] = env->regs[i];
            cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_GPRS;
        }
    } else {
        for (i = 0; i < 16; i++) {
            regs.gprs[i] = env->regs[i];
        }
        r = kvm_vcpu_ioctl(cs, KVM_SET_REGS, &regs);
        if (r < 0) {
            return r;
        }
    }

    /* Floating point */
    for (i = 0; i < 16; i++) {
        fpu.fprs[i] = env->fregs[i].ll;
    }
    fpu.fpc = env->fpc;

    r = kvm_vcpu_ioctl(cs, KVM_SET_FPU, &fpu);
    if (r < 0) {
        return r;
    }

    /* Do we need to save more than that? */
    if (level == KVM_PUT_RUNTIME_STATE) {
        return 0;
    }

    /*
     * These ONE_REGS are not protected by a capability. As they are only
     * necessary for migration we just trace a possible error, but don't
     * return with an error return code.
     */
    kvm_set_one_reg(cs, KVM_REG_S390_CPU_TIMER, &env->cputm);
    kvm_set_one_reg(cs, KVM_REG_S390_CLOCK_COMP, &env->ckc);
    kvm_set_one_reg(cs, KVM_REG_S390_TODPR, &env->todpr);
    kvm_set_one_reg(cs, KVM_REG_S390_GBEA, &env->gbea);
    kvm_set_one_reg(cs, KVM_REG_S390_PP, &env->pp);

    if (cap_async_pf) {
        r = kvm_set_one_reg(cs, KVM_REG_S390_PFTOKEN, &env->pfault_token);
        if (r < 0) {
            return r;
        }
        r = kvm_set_one_reg(cs, KVM_REG_S390_PFCOMPARE, &env->pfault_compare);
        if (r < 0) {
            return r;
        }
        r = kvm_set_one_reg(cs, KVM_REG_S390_PFSELECT, &env->pfault_select);
        if (r < 0) {
            return r;
        }
    }

    if (cap_sync_regs &&
        cs->kvm_run->kvm_valid_regs & KVM_SYNC_ACRS &&
        cs->kvm_run->kvm_valid_regs & KVM_SYNC_CRS) {
        for (i = 0; i < 16; i++) {
            cs->kvm_run->s.regs.acrs[i] = env->aregs[i];
            cs->kvm_run->s.regs.crs[i] = env->cregs[i];
        }
        cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_ACRS;
        cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_CRS;
    } else {
        for (i = 0; i < 16; i++) {
            sregs.acrs[i] = env->aregs[i];
            sregs.crs[i] = env->cregs[i];
        }
        r = kvm_vcpu_ioctl(cs, KVM_SET_SREGS, &sregs);
        if (r < 0) {
            return r;
        }
    }

    /* Finally the prefix */
    if (cap_sync_regs && cs->kvm_run->kvm_valid_regs & KVM_SYNC_PREFIX) {
        cs->kvm_run->s.regs.prefix = env->psa;
        cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_PREFIX;
    } else {
        /* prefix is only supported via sync regs */
    }
    return 0;
}

int kvm_arch_get_registers(CPUState *cs)
{
    S390CPU *cpu = S390_CPU(cs);
    CPUS390XState *env = &cpu->env;
    struct kvm_sregs sregs;
    struct kvm_regs regs;
    struct kvm_fpu fpu;
    int i, r;

    /* get the PSW */
    env->psw.addr = cs->kvm_run->psw_addr;
    env->psw.mask = cs->kvm_run->psw_mask;

    /* the GPRS */
    if (cap_sync_regs && cs->kvm_run->kvm_valid_regs & KVM_SYNC_GPRS) {
        for (i = 0; i < 16; i++) {
            env->regs[i] = cs->kvm_run->s.regs.gprs[i];
        }
    } else {
        r = kvm_vcpu_ioctl(cs, KVM_GET_REGS, &regs);
        if (r < 0) {
            return r;
        }
         for (i = 0; i < 16; i++) {
            env->regs[i] = regs.gprs[i];
        }
    }

    /* The ACRS and CRS */
    if (cap_sync_regs &&
        cs->kvm_run->kvm_valid_regs & KVM_SYNC_ACRS &&
        cs->kvm_run->kvm_valid_regs & KVM_SYNC_CRS) {
        for (i = 0; i < 16; i++) {
            env->aregs[i] = cs->kvm_run->s.regs.acrs[i];
            env->cregs[i] = cs->kvm_run->s.regs.crs[i];
        }
    } else {
        r = kvm_vcpu_ioctl(cs, KVM_GET_SREGS, &sregs);
        if (r < 0) {
            return r;
        }
         for (i = 0; i < 16; i++) {
            env->aregs[i] = sregs.acrs[i];
            env->cregs[i] = sregs.crs[i];
        }
    }

    /* Floating point */
    r = kvm_vcpu_ioctl(cs, KVM_GET_FPU, &fpu);
    if (r < 0) {
        return r;
    }
    for (i = 0; i < 16; i++) {
        env->fregs[i].ll = fpu.fprs[i];
    }
    env->fpc = fpu.fpc;

    /* The prefix */
    if (cap_sync_regs && cs->kvm_run->kvm_valid_regs & KVM_SYNC_PREFIX) {
        env->psa = cs->kvm_run->s.regs.prefix;
    }

    /*
     * These ONE_REGS are not protected by a capability. As they are only
     * necessary for migration we just trace a possible error, but don't
     * return with an error return code.
     */
    kvm_get_one_reg(cs, KVM_REG_S390_CPU_TIMER, &env->cputm);
    kvm_get_one_reg(cs, KVM_REG_S390_CLOCK_COMP, &env->ckc);
    kvm_get_one_reg(cs, KVM_REG_S390_TODPR, &env->todpr);
    kvm_get_one_reg(cs, KVM_REG_S390_GBEA, &env->gbea);
    kvm_get_one_reg(cs, KVM_REG_S390_PP, &env->pp);

    if (cap_async_pf) {
        r = kvm_get_one_reg(cs, KVM_REG_S390_PFTOKEN, &env->pfault_token);
        if (r < 0) {
            return r;
        }
        r = kvm_get_one_reg(cs, KVM_REG_S390_PFCOMPARE, &env->pfault_compare);
        if (r < 0) {
            return r;
        }
        r = kvm_get_one_reg(cs, KVM_REG_S390_PFSELECT, &env->pfault_select);
        if (r < 0) {
            return r;
        }
    }

    return 0;
}

/*
 * Legacy layout for s390:
 * Older S390 KVM requires the topmost vma of the RAM to be
 * smaller than an system defined value, which is at least 256GB.
 * Larger systems have larger values. We put the guest between
 * the end of data segment (system break) and this value. We
 * use 32GB as a base to have enough room for the system break
 * to grow. We also have to use MAP parameters that avoid
 * read-only mapping of guest pages.
 */
static void *legacy_s390_alloc(size_t size, , uint64_t *align)
{
    void *mem;

    mem = mmap((void *) 0x800000000ULL, size,
               PROT_EXEC|PROT_READ|PROT_WRITE,
               MAP_SHARED | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
    return mem == MAP_FAILED ? NULL : mem;
}

/* DIAG 501 is used for sw breakpoints */
static const uint8_t diag_501[] = {0x83, 0x24, 0x05, 0x01};

int kvm_arch_insert_sw_breakpoint(CPUState *cs, struct kvm_sw_breakpoint *bp)
{

    if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn,
                            sizeof(diag_501), 0) ||
        cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)diag_501,
                            sizeof(diag_501), 1)) {
        return -EINVAL;
    }
    return 0;
}

int kvm_arch_remove_sw_breakpoint(CPUState *cs, struct kvm_sw_breakpoint *bp)
{
    uint8_t t[sizeof(diag_501)];

    if (cpu_memory_rw_debug(cs, bp->pc, t, sizeof(diag_501), 0)) {
        return -EINVAL;
    } else if (memcmp(t, diag_501, sizeof(diag_501))) {
        return -EINVAL;
    } else if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn,
                                   sizeof(diag_501), 1)) {
        return -EINVAL;
    }

    return 0;
}

static struct kvm_hw_breakpoint *find_hw_breakpoint(target_ulong addr,
                                                    int len, int type)
{
    int n;

    for (n = 0; n < nb_hw_breakpoints; n++) {
        if (hw_breakpoints[n].addr == addr && hw_breakpoints[n].type == type &&
            (hw_breakpoints[n].len == len || len == -1)) {
            return &hw_breakpoints[n];
        }
    }

    return NULL;
}

static int insert_hw_breakpoint(target_ulong addr, int len, int type)
{
    int size;

    if (find_hw_breakpoint(addr, len, type)) {
        return -EEXIST;
    }

    size = (nb_hw_breakpoints + 1) * sizeof(struct kvm_hw_breakpoint);

    if (!hw_breakpoints) {
        nb_hw_breakpoints = 0;
        hw_breakpoints = (struct kvm_hw_breakpoint *)g_try_malloc(size);
    } else {
        hw_breakpoints =
            (struct kvm_hw_breakpoint *)g_try_realloc(hw_breakpoints, size);
    }

    if (!hw_breakpoints) {
        nb_hw_breakpoints = 0;
        return -ENOMEM;
    }

    hw_breakpoints[nb_hw_breakpoints].addr = addr;
    hw_breakpoints[nb_hw_breakpoints].len = len;
    hw_breakpoints[nb_hw_breakpoints].type = type;

    nb_hw_breakpoints++;

    return 0;
}

int kvm_arch_insert_hw_breakpoint(target_ulong addr,
                                  target_ulong len, int type)
{
    switch (type) {
    case GDB_BREAKPOINT_HW:
        type = KVM_HW_BP;
        break;
    case GDB_WATCHPOINT_WRITE:
        if (len < 1) {
            return -EINVAL;
        }
        type = KVM_HW_WP_WRITE;
        break;
    default:
        return -ENOSYS;
    }
    return insert_hw_breakpoint(addr, len, type);
}

int kvm_arch_remove_hw_breakpoint(target_ulong addr,
                                  target_ulong len, int type)
{
    int size;
    struct kvm_hw_breakpoint *bp = find_hw_breakpoint(addr, len, type);

    if (bp == NULL) {
        return -ENOENT;
    }

    nb_hw_breakpoints--;
    if (nb_hw_breakpoints > 0) {
        /*
         * In order to trim the array, move the last element to the position to
         * be removed - if necessary.
         */
        if (bp != &hw_breakpoints[nb_hw_breakpoints]) {
            *bp = hw_breakpoints[nb_hw_breakpoints];
        }
        size = nb_hw_breakpoints * sizeof(struct kvm_hw_breakpoint);
        hw_breakpoints =
             (struct kvm_hw_breakpoint *)g_realloc(hw_breakpoints, size);
    } else {
        g_free(hw_breakpoints);
        hw_breakpoints = NULL;
    }

    return 0;
}

void kvm_arch_remove_all_hw_breakpoints(void)
{
    nb_hw_breakpoints = 0;
    g_free(hw_breakpoints);
    hw_breakpoints = NULL;
}

void kvm_arch_update_guest_debug(CPUState *cpu, struct kvm_guest_debug *dbg)
{
    int i;

    if (nb_hw_breakpoints > 0) {
        dbg->arch.nr_hw_bp = nb_hw_breakpoints;
        dbg->arch.hw_bp = hw_breakpoints;

        for (i = 0; i < nb_hw_breakpoints; ++i) {
            hw_breakpoints[i].phys_addr = s390_cpu_get_phys_addr_debug(cpu,
                                                       hw_breakpoints[i].addr);
        }
        dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
    } else {
        dbg->arch.nr_hw_bp = 0;
        dbg->arch.hw_bp = NULL;
    }
}

void kvm_arch_pre_run(CPUState *cpu, struct kvm_run *run)
{
}

void kvm_arch_post_run(CPUState *cpu, struct kvm_run *run)
{
}

int kvm_arch_process_async_events(CPUState *cs)
{
    return cs->halted;
}

static int s390_kvm_irq_to_interrupt(struct kvm_s390_irq *irq,
                                     struct kvm_s390_interrupt *interrupt)
{
    int r = 0;

    interrupt->type = irq->type;
    switch (irq->type) {
    case KVM_S390_INT_VIRTIO:
        interrupt->parm = irq->u.ext.ext_params;
        /* fall through */
    case KVM_S390_INT_PFAULT_INIT:
    case KVM_S390_INT_PFAULT_DONE:
        interrupt->parm64 = irq->u.ext.ext_params2;
        break;
    case KVM_S390_PROGRAM_INT:
        interrupt->parm = irq->u.pgm.code;
        break;
    case KVM_S390_SIGP_SET_PREFIX:
        interrupt->parm = irq->u.prefix.address;
        break;
    case KVM_S390_INT_SERVICE:
        interrupt->parm = irq->u.ext.ext_params;
        break;
    case KVM_S390_MCHK:
        interrupt->parm = irq->u.mchk.cr14;
        interrupt->parm64 = irq->u.mchk.mcic;
        break;
    case KVM_S390_INT_EXTERNAL_CALL:
        interrupt->parm = irq->u.extcall.code;
        break;
    case KVM_S390_INT_EMERGENCY:
        interrupt->parm = irq->u.emerg.code;
        break;
    case KVM_S390_SIGP_STOP:
    case KVM_S390_RESTART:
        break; /* These types have no parameters */
    case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
        interrupt->parm = irq->u.io.subchannel_id << 16;
        interrupt->parm |= irq->u.io.subchannel_nr;
        interrupt->parm64 = (uint64_t)irq->u.io.io_int_parm << 32;
        interrupt->parm64 |= irq->u.io.io_int_word;
        break;
    default:
        r = -EINVAL;
        break;
    }
    return r;
}

void kvm_s390_vcpu_interrupt(S390CPU *cpu, struct kvm_s390_irq *irq)
{
    struct kvm_s390_interrupt kvmint = {};
    CPUState *cs = CPU(cpu);
    int r;

    r = s390_kvm_irq_to_interrupt(irq, &kvmint);
    if (r < 0) {
        fprintf(stderr, "%s called with bogus interrupt\n", __func__);
        exit(1);
    }

    r = kvm_vcpu_ioctl(cs, KVM_S390_INTERRUPT, &kvmint);
    if (r < 0) {
        fprintf(stderr, "KVM failed to inject interrupt\n");
        exit(1);
    }
}

static void __kvm_s390_floating_interrupt(struct kvm_s390_irq *irq)
{
    struct kvm_s390_interrupt kvmint = {};
    int r;

    r = s390_kvm_irq_to_interrupt(irq, &kvmint);
    if (r < 0) {
        fprintf(stderr, "%s called with bogus interrupt\n", __func__);
        exit(1);
    }

    r = kvm_vm_ioctl(kvm_state, KVM_S390_INTERRUPT, &kvmint);
    if (r < 0) {
        fprintf(stderr, "KVM failed to inject interrupt\n");
        exit(1);
    }
}

void kvm_s390_floating_interrupt(struct kvm_s390_irq *irq)
{
    static bool use_flic = true;
    int r;

    if (use_flic) {
        r = kvm_s390_inject_flic(irq);
        if (r == -ENOSYS) {
            use_flic = false;
        }
        if (!r) {
            return;
        }
    }
    __kvm_s390_floating_interrupt(irq);
}

void kvm_s390_virtio_irq(int config_change, uint64_t token)
{
    struct kvm_s390_irq irq = {
        .type = KVM_S390_INT_VIRTIO,
        .u.ext.ext_params = config_change,
        .u.ext.ext_params2 = token,
    };

    kvm_s390_floating_interrupt(&irq);
}

void kvm_s390_service_interrupt(uint32_t parm)
{
    struct kvm_s390_irq irq = {
        .type = KVM_S390_INT_SERVICE,
        .u.ext.ext_params = parm,
    };

    kvm_s390_floating_interrupt(&irq);
}

static void enter_pgmcheck(S390CPU *cpu, uint16_t code)
{
    struct kvm_s390_irq irq = {
        .type = KVM_S390_PROGRAM_INT,
        .u.pgm.code = code,
    };

    kvm_s390_vcpu_interrupt(cpu, &irq);
}

static int kvm_sclp_service_call(S390CPU *cpu, struct kvm_run *run,
                                 uint16_t ipbh0)
{
    CPUS390XState *env = &cpu->env;
    uint64_t sccb;
    uint32_t code;
    int r = 0;

    cpu_synchronize_state(CPU(cpu));
    sccb = env->regs[ipbh0 & 0xf];
    code = env->regs[(ipbh0 & 0xf0) >> 4];

    r = sclp_service_call(env, sccb, code);
    if (r < 0) {
        enter_pgmcheck(cpu, -r);
    } else {
        setcc(cpu, r);
    }

    return 0;
}

static int handle_b2(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
{
    CPUS390XState *env = &cpu->env;
    int rc = 0;
    uint16_t ipbh0 = (run->s390_sieic.ipb & 0xffff0000) >> 16;

    cpu_synchronize_state(CPU(cpu));

    switch (ipa1) {
    case PRIV_B2_XSCH:
        ioinst_handle_xsch(cpu, env->regs[1]);
        break;
    case PRIV_B2_CSCH:
        ioinst_handle_csch(cpu, env->regs[1]);
        break;
    case PRIV_B2_HSCH:
        ioinst_handle_hsch(cpu, env->regs[1]);
        break;
    case PRIV_B2_MSCH:
        ioinst_handle_msch(cpu, env->regs[1], run->s390_sieic.ipb);
        break;
    case PRIV_B2_SSCH:
        ioinst_handle_ssch(cpu, env->regs[1], run->s390_sieic.ipb);
        break;
    case PRIV_B2_STCRW:
        ioinst_handle_stcrw(cpu, run->s390_sieic.ipb);
        break;
    case PRIV_B2_STSCH:
        ioinst_handle_stsch(cpu, env->regs[1], run->s390_sieic.ipb);
        break;
    case PRIV_B2_TSCH:
        /* We should only get tsch via KVM_EXIT_S390_TSCH. */
        fprintf(stderr, "Spurious tsch intercept\n");
        break;
    case PRIV_B2_CHSC:
        ioinst_handle_chsc(cpu, run->s390_sieic.ipb);
        break;
    case PRIV_B2_TPI:
        /* This should have been handled by kvm already. */
        fprintf(stderr, "Spurious tpi intercept\n");
        break;
    case PRIV_B2_SCHM:
        ioinst_handle_schm(cpu, env->regs[1], env->regs[2],
                           run->s390_sieic.ipb);
        break;
    case PRIV_B2_RSCH:
        ioinst_handle_rsch(cpu, env->regs[1]);
        break;
    case PRIV_B2_RCHP:
        ioinst_handle_rchp(cpu, env->regs[1]);
        break;
    case PRIV_B2_STCPS:
        /* We do not provide this instruction, it is suppressed. */
        break;
    case PRIV_B2_SAL:
        ioinst_handle_sal(cpu, env->regs[1]);
        break;
    case PRIV_B2_SIGA:
        /* Not provided, set CC = 3 for subchannel not operational */
        setcc(cpu, 3);
        break;
    case PRIV_B2_SCLP_CALL:
        rc = kvm_sclp_service_call(cpu, run, ipbh0);
        break;
    default:
        rc = -1;
        DPRINTF("KVM: unhandled PRIV: 0xb2%x\n", ipa1);
        break;
    }

    return rc;
}

static int handle_b9(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
{
    int r = 0;

    switch (ipa1) {
    case PRIV_B9_EQBS:
        /* just inject exception */
        r = -1;
        break;
    default:
        r = -1;
        DPRINTF("KVM: unhandled PRIV: 0xb9%x\n", ipa1);
        break;
    }

    return r;
}

static int handle_eb(S390CPU *cpu, struct kvm_run *run, uint8_t ipbl)
{
    int r = 0;

    switch (ipbl) {
    case PRIV_EB_SQBS:
        /* just inject exception */
        r = -1;
        break;
    default:
        r = -1;
        DPRINTF("KVM: unhandled PRIV: 0xeb%x\n", ipbl);
        break;
    }

    return r;
}

static int handle_hypercall(S390CPU *cpu, struct kvm_run *run)
{
    CPUS390XState *env = &cpu->env;
    int ret;

    cpu_synchronize_state(CPU(cpu));
    ret = s390_virtio_hypercall(env);
    if (ret == -EINVAL) {
        enter_pgmcheck(cpu, PGM_SPECIFICATION);
        return 0;
    }

    return ret;
}

static void kvm_handle_diag_308(S390CPU *cpu, struct kvm_run *run)
{
    uint64_t r1, r3;

    cpu_synchronize_state(CPU(cpu));
    r1 = (run->s390_sieic.ipa & 0x00f0) >> 8;
    r3 = run->s390_sieic.ipa & 0x000f;
    handle_diag_308(&cpu->env, r1, r3);
}

static int handle_sw_breakpoint(S390CPU *cpu, struct kvm_run *run)
{
    CPUS390XState *env = &cpu->env;
    unsigned long pc;

    cpu_synchronize_state(CPU(cpu));

    pc = env->psw.addr - 4;
    if (kvm_find_sw_breakpoint(CPU(cpu), pc)) {
        env->psw.addr = pc;
        return EXCP_DEBUG;
    }

    return -ENOENT;
}

#define DIAG_KVM_CODE_MASK 0x000000000000ffff

static int handle_diag(S390CPU *cpu, struct kvm_run *run, uint32_t ipb)
{
    int r = 0;
    uint16_t func_code;

    /*
     * For any diagnose call we support, bits 48-63 of the resulting
     * address specify the function code; the remainder is ignored.
     */
    func_code = decode_basedisp_rs(&cpu->env, ipb) & DIAG_KVM_CODE_MASK;
    switch (func_code) {
    case DIAG_IPL:
        kvm_handle_diag_308(cpu, run);
        break;
    case DIAG_KVM_HYPERCALL:
        r = handle_hypercall(cpu, run);
        break;
    case DIAG_KVM_BREAKPOINT:
        r = handle_sw_breakpoint(cpu, run);
        break;
    default:
        DPRINTF("KVM: unknown DIAG: 0x%x\n", func_code);
        r = -1;
        break;
    }

    return r;
}

static void sigp_cpu_start(void *arg)
{
    CPUState *cs = arg;
    S390CPU *cpu = S390_CPU(cs);

    s390_cpu_set_state(CPU_STATE_OPERATING, cpu);
    DPRINTF("DONE: KVM cpu start: %p\n", &cpu->env);
}

static void sigp_cpu_restart(void *arg)
{
    CPUState *cs = arg;
    S390CPU *cpu = S390_CPU(cs);
    struct kvm_s390_irq irq = {
        .type = KVM_S390_RESTART,
    };

    kvm_s390_vcpu_interrupt(cpu, &irq);
    s390_cpu_set_state(CPU_STATE_OPERATING, cpu);
}

int kvm_s390_cpu_restart(S390CPU *cpu)
{
    run_on_cpu(CPU(cpu), sigp_cpu_restart, CPU(cpu));
    DPRINTF("DONE: KVM cpu restart: %p\n", &cpu->env);
    return 0;
}

static void sigp_initial_cpu_reset(void *arg)
{
    CPUState *cpu = arg;
    S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);

    cpu_synchronize_state(cpu);
    scc->initial_cpu_reset(cpu);
    cpu_synchronize_post_reset(cpu);
}

static void sigp_cpu_reset(void *arg)
{
    CPUState *cpu = arg;
    S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);

    cpu_synchronize_state(cpu);
    scc->cpu_reset(cpu);
    cpu_synchronize_post_reset(cpu);
}

#define SIGP_ORDER_MASK 0x000000ff

static int handle_sigp(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
{
    CPUS390XState *env = &cpu->env;
    uint8_t order_code;
    uint16_t cpu_addr;
    S390CPU *target_cpu;
    uint64_t *statusreg = &env->regs[ipa1 >> 4];
    int cc;

    cpu_synchronize_state(CPU(cpu));

    /* get order code */
    order_code = decode_basedisp_rs(env, run->s390_sieic.ipb) & SIGP_ORDER_MASK;

    cpu_addr = env->regs[ipa1 & 0x0f];
    target_cpu = s390_cpu_addr2state(cpu_addr);
    if (target_cpu == NULL) {
        cc = 3;    /* not operational */
        goto out;
    }

    switch (order_code) {
    case SIGP_START:
        run_on_cpu(CPU(target_cpu), sigp_cpu_start, CPU(target_cpu));
        cc = 0;
        break;
    case SIGP_RESTART:
        run_on_cpu(CPU(target_cpu), sigp_cpu_restart, CPU(target_cpu));
        cc = 0;
        break;
    case SIGP_SET_ARCH:
        *statusreg &= 0xffffffff00000000UL;
        *statusreg |= SIGP_STAT_INVALID_PARAMETER;
        cc = 1;   /* status stored */
        break;
    case SIGP_INITIAL_CPU_RESET:
        run_on_cpu(CPU(target_cpu), sigp_initial_cpu_reset, CPU(target_cpu));
        cc = 0;
        break;
    case SIGP_CPU_RESET:
        run_on_cpu(CPU(target_cpu), sigp_cpu_reset, CPU(target_cpu));
        cc = 0;
        break;
    default:
        DPRINTF("KVM: unknown SIGP: 0x%x\n", order_code);
        *statusreg &= 0xffffffff00000000UL;
        *statusreg |= SIGP_STAT_INVALID_ORDER;
        cc = 1;   /* status stored */
        break;
    }

out:
    setcc(cpu, cc);
    return 0;
}

static int handle_instruction(S390CPU *cpu, struct kvm_run *run)
{
    unsigned int ipa0 = (run->s390_sieic.ipa & 0xff00);
    uint8_t ipa1 = run->s390_sieic.ipa & 0x00ff;
    int r = -1;

    DPRINTF("handle_instruction 0x%x 0x%x\n",
            run->s390_sieic.ipa, run->s390_sieic.ipb);
    switch (ipa0) {
    case IPA0_B2:
        r = handle_b2(cpu, run, ipa1);
        break;
    case IPA0_B9:
        r = handle_b9(cpu, run, ipa1);
        break;
    case IPA0_EB:
        r = handle_eb(cpu, run, run->s390_sieic.ipb & 0xff);
        break;
    case IPA0_DIAG:
        r = handle_diag(cpu, run, run->s390_sieic.ipb);
        break;
    case IPA0_SIGP:
        r = handle_sigp(cpu, run, ipa1);
        break;
    }

    if (r < 0) {
        r = 0;
        enter_pgmcheck(cpu, 0x0001);
    }

    return r;
}

static bool is_special_wait_psw(CPUState *cs)
{
    /* signal quiesce */
    return cs->kvm_run->psw_addr == 0xfffUL;
}

static void guest_panicked(void)
{
    qapi_event_send_guest_panicked(GUEST_PANIC_ACTION_PAUSE,
                                   &error_abort);
    vm_stop(RUN_STATE_GUEST_PANICKED);
}

static void unmanageable_intercept(S390CPU *cpu, const char *str, int pswoffset)
{
    CPUState *cs = CPU(cpu);

    error_report("Unmanageable %s! CPU%i new PSW: 0x%016lx:%016lx",
                 str, cs->cpu_index, ldq_phys(cs->as, cpu->env.psa + pswoffset),
                 ldq_phys(cs->as, cpu->env.psa + pswoffset + 8));
    s390_cpu_halt(cpu);
    guest_panicked();
}

static int handle_intercept(S390CPU *cpu)
{
    CPUState *cs = CPU(cpu);
    struct kvm_run *run = cs->kvm_run;
    int icpt_code = run->s390_sieic.icptcode;
    int r = 0;

    DPRINTF("intercept: 0x%x (at 0x%lx)\n", icpt_code,
            (long)cs->kvm_run->psw_addr);
    switch (icpt_code) {
        case ICPT_INSTRUCTION:
            r = handle_instruction(cpu, run);
            break;
        case ICPT_PROGRAM:
            unmanageable_intercept(cpu, "program interrupt",
                                   offsetof(LowCore, program_new_psw));
            r = EXCP_HALTED;
            break;
        case ICPT_EXT_INT:
            unmanageable_intercept(cpu, "external interrupt",
                                   offsetof(LowCore, external_new_psw));
            r = EXCP_HALTED;
            break;
        case ICPT_WAITPSW:
            /* disabled wait, since enabled wait is handled in kernel */
            cpu_synchronize_state(cs);
            if (s390_cpu_halt(cpu) == 0) {
                if (is_special_wait_psw(cs)) {
                    qemu_system_shutdown_request();
                } else {
                    guest_panicked();
                }
            }
            r = EXCP_HALTED;
            break;
        case ICPT_CPU_STOP:
            if (s390_cpu_set_state(CPU_STATE_STOPPED, cpu) == 0) {
                qemu_system_shutdown_request();
            }
            r = EXCP_HALTED;
            break;
        case ICPT_SOFT_INTERCEPT:
            fprintf(stderr, "KVM unimplemented icpt SOFT\n");
            exit(1);
            break;
        case ICPT_IO:
            fprintf(stderr, "KVM unimplemented icpt IO\n");
            exit(1);
            break;
        default:
            fprintf(stderr, "Unknown intercept code: %d\n", icpt_code);
            exit(1);
            break;
    }

    return r;
}

static int handle_tsch(S390CPU *cpu)
{
    CPUS390XState *env = &cpu->env;
    CPUState *cs = CPU(cpu);
    struct kvm_run *run = cs->kvm_run;
    int ret;

    cpu_synchronize_state(cs);

    ret = ioinst_handle_tsch(env, env->regs[1], run->s390_tsch.ipb);
    if (ret >= 0) {
        /* Success; set condition code. */
        setcc(cpu, ret);
        ret = 0;
    } else if (ret < -1) {
        /*
         * Failure.
         * If an I/O interrupt had been dequeued, we have to reinject it.
         */
        if (run->s390_tsch.dequeued) {
            kvm_s390_io_interrupt(run->s390_tsch.subchannel_id,
                                  run->s390_tsch.subchannel_nr,
                                  run->s390_tsch.io_int_parm,
                                  run->s390_tsch.io_int_word);
        }
        ret = 0;
    }
    return ret;
}

static int kvm_arch_handle_debug_exit(S390CPU *cpu)
{
    CPUState *cs = CPU(cpu);
    struct kvm_run *run = cs->kvm_run;

    int ret = 0;
    struct kvm_debug_exit_arch *arch_info = &run->debug.arch;

    switch (arch_info->type) {
    case KVM_HW_WP_WRITE:
        if (find_hw_breakpoint(arch_info->addr, -1, arch_info->type)) {
            cs->watchpoint_hit = &hw_watchpoint;
            hw_watchpoint.vaddr = arch_info->addr;
            hw_watchpoint.flags = BP_MEM_WRITE;
            ret = EXCP_DEBUG;
        }
        break;
    case KVM_HW_BP:
        if (find_hw_breakpoint(arch_info->addr, -1, arch_info->type)) {
            ret = EXCP_DEBUG;
        }
        break;
    case KVM_SINGLESTEP:
        if (cs->singlestep_enabled) {
            ret = EXCP_DEBUG;
        }
        break;
    default:
        ret = -ENOSYS;
    }

    return ret;
}

int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
{
    S390CPU *cpu = S390_CPU(cs);
    int ret = 0;

    switch (run->exit_reason) {
        case KVM_EXIT_S390_SIEIC:
            ret = handle_intercept(cpu);
            break;
        case KVM_EXIT_S390_RESET:
            qemu_system_reset_request();
            break;
        case KVM_EXIT_S390_TSCH:
            ret = handle_tsch(cpu);
            break;
        case KVM_EXIT_DEBUG:
            ret = kvm_arch_handle_debug_exit(cpu);
            break;
        default:
            fprintf(stderr, "Unknown KVM exit: %d\n", run->exit_reason);
            break;
    }

    if (ret == 0) {
        ret = EXCP_INTERRUPT;
    }
    return ret;
}

bool kvm_arch_stop_on_emulation_error(CPUState *cpu)
{
    return true;
}

int kvm_arch_on_sigbus_vcpu(CPUState *cpu, int code, void *addr)
{
    return 1;
}

int kvm_arch_on_sigbus(int code, void *addr)
{
    return 1;
}

void kvm_s390_io_interrupt(uint16_t subchannel_id,
                           uint16_t subchannel_nr, uint32_t io_int_parm,
                           uint32_t io_int_word)
{
    struct kvm_s390_irq irq = {
        .u.io.subchannel_id = subchannel_id,
        .u.io.subchannel_nr = subchannel_nr,
        .u.io.io_int_parm = io_int_parm,
        .u.io.io_int_word = io_int_word,
    };

    if (io_int_word & IO_INT_WORD_AI) {
        irq.type = KVM_S390_INT_IO(1, 0, 0, 0);
    } else {
        irq.type = ((subchannel_id & 0xff00) << 24) |
            ((subchannel_id & 0x00060) << 22) | (subchannel_nr << 16);
    }
    kvm_s390_floating_interrupt(&irq);
}

void kvm_s390_crw_mchk(void)
{
    struct kvm_s390_irq irq = {
        .type = KVM_S390_MCHK,
        .u.mchk.cr14 = 1 << 28,
        .u.mchk.mcic = 0x00400f1d40330000ULL,
    };
    kvm_s390_floating_interrupt(&irq);
}

void kvm_s390_enable_css_support(S390CPU *cpu)
{
    int r;

    /* Activate host kernel channel subsystem support. */
    r = kvm_vcpu_enable_cap(CPU(cpu), KVM_CAP_S390_CSS_SUPPORT, 0);
    assert(r == 0);
}

void kvm_arch_init_irq_routing(KVMState *s)
{
    /*
     * Note that while irqchip capabilities generally imply that cpustates
     * are handled in-kernel, it is not true for s390 (yet); therefore, we
     * have to override the common code kvm_halt_in_kernel_allowed setting.
     */
    if (kvm_check_extension(s, KVM_CAP_IRQ_ROUTING)) {
        kvm_gsi_routing_allowed = true;
        kvm_halt_in_kernel_allowed = false;
    }
}

int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch,
                                    int vq, bool assign)
{
    struct kvm_ioeventfd kick = {
        .flags = KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY |
        KVM_IOEVENTFD_FLAG_DATAMATCH,
        .fd = event_notifier_get_fd(notifier),
        .datamatch = vq,
        .addr = sch,
        .len = 8,
    };
    if (!kvm_check_extension(kvm_state, KVM_CAP_IOEVENTFD)) {
        return -ENOSYS;
    }
    if (!assign) {
        kick.flags |= KVM_IOEVENTFD_FLAG_DEASSIGN;
    }
    return kvm_vm_ioctl(kvm_state, KVM_IOEVENTFD, &kick);
}

int kvm_s390_get_memslot_count(KVMState *s)
{
    return kvm_check_extension(s, KVM_CAP_NR_MEMSLOTS);
}

int kvm_s390_set_cpu_state(S390CPU *cpu, uint8_t cpu_state)
{
    struct kvm_mp_state mp_state = {};
    int ret;

    /* the kvm part might not have been initialized yet */
    if (CPU(cpu)->kvm_state == NULL) {
        return 0;
    }

    switch (cpu_state) {
    case CPU_STATE_STOPPED:
        mp_state.mp_state = KVM_MP_STATE_STOPPED;
        break;
    case CPU_STATE_CHECK_STOP:
        mp_state.mp_state = KVM_MP_STATE_CHECK_STOP;
        break;
    case CPU_STATE_OPERATING:
        mp_state.mp_state = KVM_MP_STATE_OPERATING;
        break;
    case CPU_STATE_LOAD:
        mp_state.mp_state = KVM_MP_STATE_LOAD;
        break;
    default:
        error_report("Requested CPU state is not a valid S390 CPU state: %u",
                     cpu_state);
        exit(1);
    }

    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MP_STATE, &mp_state);
    if (ret) {
        trace_kvm_failed_cpu_state_set(CPU(cpu)->cpu_index, cpu_state,
                                       strerror(-ret));
    }

    return ret;
}