Archipelago » qemu

/*

 * Channel subsystem base support.

 *

 * Copyright 2012 IBM Corp.

 * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or (at

 * your option) any later version. See the COPYING file in the top-level

 * directory.

 */

#include <hw/qdev.h>

#include "qemu/bitops.h"

#include "cpu.h"

#include "ioinst.h"

#include "css.h"

#include "trace.h"

typedef struct CrwContainer {

    CRW crw;

    QTAILQ_ENTRY(CrwContainer) sibling;

} CrwContainer;

typedef struct ChpInfo {

    uint8_t in_use;

    uint8_t type;

    uint8_t is_virtual;

} ChpInfo;

typedef struct SubchSet {

    SubchDev *sch[MAX_SCHID + 1];

    unsigned long schids_used[BITS_TO_LONGS(MAX_SCHID + 1)];

    unsigned long devnos_used[BITS_TO_LONGS(MAX_SCHID + 1)];

} SubchSet;

typedef struct CssImage {

    SubchSet *sch_set[MAX_SSID + 1];

    ChpInfo chpids[MAX_CHPID + 1];

} CssImage;

typedef struct ChannelSubSys {

    QTAILQ_HEAD(, CrwContainer) pending_crws;

    bool do_crw_mchk;

    bool crws_lost;

    uint8_t max_cssid;

    uint8_t max_ssid;

    bool chnmon_active;

    uint64_t chnmon_area;

    CssImage *css[MAX_CSSID + 1];

    uint8_t default_cssid;

} ChannelSubSys;

static ChannelSubSys *channel_subsys;

int css_create_css_image(uint8_t cssid, bool default_image)

{

    trace_css_new_image(cssid, default_image ? "(default)" : "");

    if (cssid > MAX_CSSID) {

        return -EINVAL;

    }

    if (channel_subsys->css[cssid]) {

        return -EBUSY;

    }

    channel_subsys->css[cssid] = g_malloc0(sizeof(CssImage));

    if (default_image) {

        channel_subsys->default_cssid = cssid;

    }

    return 0;

}

uint16_t css_build_subchannel_id(SubchDev *sch)

{

    if (channel_subsys->max_cssid > 0) {

        return (sch->cssid << 8) | (1 << 3) | (sch->ssid << 1) | 1;

    }

    return (sch->ssid << 1) | 1;

}

static void css_inject_io_interrupt(SubchDev *sch)

{

    S390CPU *cpu = s390_cpu_addr2state(0);

    uint8_t isc = (sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ISC) >> 11;

    trace_css_io_interrupt(sch->cssid, sch->ssid, sch->schid,

                           sch->curr_status.pmcw.intparm, isc, "");

    s390_io_interrupt(cpu,

                      css_build_subchannel_id(sch),

                      sch->schid,

                      sch->curr_status.pmcw.intparm,

                      isc << 27);

}

void css_conditional_io_interrupt(SubchDev *sch)

{

    /*

     * If the subchannel is not currently status pending, make it pending

     * with alert status.

     */

    if (!(sch->curr_status.scsw.ctrl & SCSW_STCTL_STATUS_PEND)) {

        S390CPU *cpu = s390_cpu_addr2state(0);

        uint8_t isc = (sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ISC) >> 11;

        trace_css_io_interrupt(sch->cssid, sch->ssid, sch->schid,

                               sch->curr_status.pmcw.intparm, isc,

                               "(unsolicited)");

        sch->curr_status.scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;

        sch->curr_status.scsw.ctrl |=

            SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;

        /* Inject an I/O interrupt. */

        s390_io_interrupt(cpu,

                          css_build_subchannel_id(sch),

                          sch->schid,

                          sch->curr_status.pmcw.intparm,

                          isc << 27);

    }

}

static void sch_handle_clear_func(SubchDev *sch)

{

    PMCW *p = &sch->curr_status.pmcw;

    SCSW *s = &sch->curr_status.scsw;

    int path;

    /* Path management: In our simple css, we always choose the only path. */

    path = 0x80;

    /* Reset values prior to 'issueing the clear signal'. */

    p->lpum = 0;

    p->pom = 0xff;

    s->flags &= ~SCSW_FLAGS_MASK_PNO;

    /* We always 'attempt to issue the clear signal', and we always succeed. */

    sch->orb = NULL;

    sch->channel_prog = 0x0;

    sch->last_cmd_valid = false;

    s->ctrl &= ~SCSW_ACTL_CLEAR_PEND;

    s->ctrl |= SCSW_STCTL_STATUS_PEND;

    s->dstat = 0;

    s->cstat = 0;

    p->lpum = path;

}

static void sch_handle_halt_func(SubchDev *sch)

{

    PMCW *p = &sch->curr_status.pmcw;

    SCSW *s = &sch->curr_status.scsw;

    int path;

    /* Path management: In our simple css, we always choose the only path. */

    path = 0x80;

    /* We always 'attempt to issue the halt signal', and we always succeed. */

    sch->orb = NULL;

    sch->channel_prog = 0x0;

    sch->last_cmd_valid = false;

    s->ctrl &= ~SCSW_ACTL_HALT_PEND;

    s->ctrl |= SCSW_STCTL_STATUS_PEND;

    if ((s->ctrl & (SCSW_ACTL_SUBCH_ACTIVE | SCSW_ACTL_DEVICE_ACTIVE)) ||

        !((s->ctrl & SCSW_ACTL_START_PEND) ||

          (s->ctrl & SCSW_ACTL_SUSP))) {

        s->dstat = SCSW_DSTAT_DEVICE_END;

    }

    s->cstat = 0;

    p->lpum = path;

}

static void copy_sense_id_to_guest(SenseId *dest, SenseId *src)

{

    int i;

    dest->reserved = src->reserved;

    dest->cu_type = cpu_to_be16(src->cu_type);

    dest->cu_model = src->cu_model;

    dest->dev_type = cpu_to_be16(src->dev_type);

    dest->dev_model = src->dev_model;

    dest->unused = src->unused;

    for (i = 0; i < ARRAY_SIZE(dest->ciw); i++) {

        dest->ciw[i].type = src->ciw[i].type;

        dest->ciw[i].command = src->ciw[i].command;

        dest->ciw[i].count = cpu_to_be16(src->ciw[i].count);

    }

}

static CCW1 copy_ccw_from_guest(hwaddr addr)

{

    CCW1 tmp;

    CCW1 ret;

    cpu_physical_memory_read(addr, &tmp, sizeof(tmp));

    ret.cmd_code = tmp.cmd_code;

    ret.flags = tmp.flags;

    ret.count = be16_to_cpu(tmp.count);

    ret.cda = be32_to_cpu(tmp.cda);

    return ret;

}

static int css_interpret_ccw(SubchDev *sch, hwaddr ccw_addr)

{

    int ret;

    bool check_len;

    int len;

    CCW1 ccw;

    if (!ccw_addr) {

        return -EIO;

    }

    ccw = copy_ccw_from_guest(ccw_addr);

    /* Check for invalid command codes. */

    if ((ccw.cmd_code & 0x0f) == 0) {

        return -EINVAL;

    }

    if (((ccw.cmd_code & 0x0f) == CCW_CMD_TIC) &&

        ((ccw.cmd_code & 0xf0) != 0)) {

        return -EINVAL;

    }

    if (ccw.flags & CCW_FLAG_SUSPEND) {

        return -EINPROGRESS;

    }

    check_len = !((ccw.flags & CCW_FLAG_SLI) && !(ccw.flags & CCW_FLAG_DC));

    /* Look at the command. */

    switch (ccw.cmd_code) {

    case CCW_CMD_NOOP:

        /* Nothing to do. */

        ret = 0;

        break;

    case CCW_CMD_BASIC_SENSE:

        if (check_len) {

            if (ccw.count != sizeof(sch->sense_data)) {

                ret = -EINVAL;

                break;

            }

        }

        len = MIN(ccw.count, sizeof(sch->sense_data));

        cpu_physical_memory_write(ccw.cda, sch->sense_data, len);

        sch->curr_status.scsw.count = ccw.count - len;

        memset(sch->sense_data, 0, sizeof(sch->sense_data));

        ret = 0;

        break;

    case CCW_CMD_SENSE_ID:

    {

        SenseId sense_id;

        copy_sense_id_to_guest(&sense_id, &sch->id);

        /* Sense ID information is device specific. */

        if (check_len) {

            if (ccw.count != sizeof(sense_id)) {

                ret = -EINVAL;

                break;

            }

        }

        len = MIN(ccw.count, sizeof(sense_id));

        /*

         * Only indicate 0xff in the first sense byte if we actually

         * have enough place to store at least bytes 0-3.

         */

        if (len >= 4) {

            sense_id.reserved = 0xff;

        } else {

            sense_id.reserved = 0;

        }

        cpu_physical_memory_write(ccw.cda, &sense_id, len);

        sch->curr_status.scsw.count = ccw.count - len;

        ret = 0;

        break;

    }

    case CCW_CMD_TIC:

        if (sch->last_cmd_valid && (sch->last_cmd.cmd_code == CCW_CMD_TIC)) {

            ret = -EINVAL;

            break;

        }

        if (ccw.flags & (CCW_FLAG_CC | CCW_FLAG_DC)) {

            ret = -EINVAL;

            break;

        }

        sch->channel_prog = ccw.cda;

        ret = -EAGAIN;

        break;

    default:

        if (sch->ccw_cb) {

            /* Handle device specific commands. */

            ret = sch->ccw_cb(sch, ccw);

        } else {

            ret = -ENOSYS;

        }

        break;

    }

    sch->last_cmd = ccw;

    sch->last_cmd_valid = true;

    if (ret == 0) {

        if (ccw.flags & CCW_FLAG_CC) {

            sch->channel_prog += 8;

            ret = -EAGAIN;

        }

    }

    return ret;

}

static void sch_handle_start_func(SubchDev *sch)

{

    PMCW *p = &sch->curr_status.pmcw;

    SCSW *s = &sch->curr_status.scsw;

    ORB *orb = sch->orb;

    int path;

    int ret;

    /* Path management: In our simple css, we always choose the only path. */

    path = 0x80;

    if (!(s->ctrl & SCSW_ACTL_SUSP)) {

        /* Look at the orb and try to execute the channel program. */

        p->intparm = orb->intparm;

        if (!(orb->lpm & path)) {

            /* Generate a deferred cc 3 condition. */

            s->flags |= SCSW_FLAGS_MASK_CC;

            s->ctrl &= ~SCSW_CTRL_MASK_STCTL;

            s->ctrl |= (SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND);

            return;

        }

    } else {

        s->ctrl &= ~(SCSW_ACTL_SUSP | SCSW_ACTL_RESUME_PEND);

    }

    sch->last_cmd_valid = false;

    do {

        ret = css_interpret_ccw(sch, sch->channel_prog);

        switch (ret) {

        case -EAGAIN:

            /* ccw chain, continue processing */

            break;

        case 0:

            /* success */

            s->ctrl &= ~SCSW_ACTL_START_PEND;

            s->ctrl &= ~SCSW_CTRL_MASK_STCTL;

            s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |

                    SCSW_STCTL_STATUS_PEND;

            s->dstat = SCSW_DSTAT_CHANNEL_END | SCSW_DSTAT_DEVICE_END;

            break;

        case -ENOSYS:

            /* unsupported command, generate unit check (command reject) */

            s->ctrl &= ~SCSW_ACTL_START_PEND;

            s->dstat = SCSW_DSTAT_UNIT_CHECK;

            /* Set sense bit 0 in ecw0. */

            sch->sense_data[0] = 0x80;

            s->ctrl &= ~SCSW_CTRL_MASK_STCTL;

            s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |

                    SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;

            break;

        case -EFAULT:

            /* memory problem, generate channel data check */

            s->ctrl &= ~SCSW_ACTL_START_PEND;

            s->cstat = SCSW_CSTAT_DATA_CHECK;

            s->ctrl &= ~SCSW_CTRL_MASK_STCTL;

            s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |

                    SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;

            break;

        case -EBUSY:

            /* subchannel busy, generate deferred cc 1 */

            s->flags &= ~SCSW_FLAGS_MASK_CC;

            s->flags |= (1 << 8);

            s->ctrl &= ~SCSW_CTRL_MASK_STCTL;

            s->ctrl |= SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;

            break;

        case -EINPROGRESS:

            /* channel program has been suspended */

            s->ctrl &= ~SCSW_ACTL_START_PEND;

            s->ctrl |= SCSW_ACTL_SUSP;

            break;

        default:

            /* error, generate channel program check */

            s->ctrl &= ~SCSW_ACTL_START_PEND;

            s->cstat = SCSW_CSTAT_PROG_CHECK;

            s->ctrl &= ~SCSW_CTRL_MASK_STCTL;

            s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |

                    SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;

            break;

        }

    } while (ret == -EAGAIN);

}

/*

 * On real machines, this would run asynchronously to the main vcpus.

 * We might want to make some parts of the ssch handling (interpreting

 * read/writes) asynchronous later on if we start supporting more than

 * our current very simple devices.

 */

static void do_subchannel_work(SubchDev *sch)

{

    SCSW *s = &sch->curr_status.scsw;

    if (s->ctrl & SCSW_FCTL_CLEAR_FUNC) {

        sch_handle_clear_func(sch);

    } else if (s->ctrl & SCSW_FCTL_HALT_FUNC) {

        sch_handle_halt_func(sch);

    } else if (s->ctrl & SCSW_FCTL_START_FUNC) {

        sch_handle_start_func(sch);

    } else {

        /* Cannot happen. */

        return;

    }

    css_inject_io_interrupt(sch);

}

static void copy_pmcw_to_guest(PMCW *dest, const PMCW *src)

{

    int i;

    dest->intparm = cpu_to_be32(src->intparm);

    dest->flags = cpu_to_be16(src->flags);

    dest->devno = cpu_to_be16(src->devno);

    dest->lpm = src->lpm;

    dest->pnom = src->pnom;

    dest->lpum = src->lpum;

    dest->pim = src->pim;

    dest->mbi = cpu_to_be16(src->mbi);

    dest->pom = src->pom;

    dest->pam = src->pam;

    for (i = 0; i < ARRAY_SIZE(dest->chpid); i++) {

        dest->chpid[i] = src->chpid[i];

    }

    dest->chars = cpu_to_be32(src->chars);

}

static void copy_scsw_to_guest(SCSW *dest, const SCSW *src)

{

    dest->flags = cpu_to_be16(src->flags);

    dest->ctrl = cpu_to_be16(src->ctrl);

    dest->cpa = cpu_to_be32(src->cpa);

    dest->dstat = src->dstat;

    dest->cstat = src->cstat;

    dest->count = cpu_to_be16(src->count);

}

static void copy_schib_to_guest(SCHIB *dest, const SCHIB *src)

{

    int i;

    copy_pmcw_to_guest(&dest->pmcw, &src->pmcw);

    copy_scsw_to_guest(&dest->scsw, &src->scsw);

    dest->mba = cpu_to_be64(src->mba);

    for (i = 0; i < ARRAY_SIZE(dest->mda); i++) {

        dest->mda[i] = src->mda[i];

    }

}

int css_do_stsch(SubchDev *sch, SCHIB *schib)

{

    /* Use current status. */

    copy_schib_to_guest(schib, &sch->curr_status);

    return 0;

}

static void copy_pmcw_from_guest(PMCW *dest, const PMCW *src)

{

    int i;

    dest->intparm = be32_to_cpu(src->intparm);

    dest->flags = be16_to_cpu(src->flags);

    dest->devno = be16_to_cpu(src->devno);

    dest->lpm = src->lpm;

    dest->pnom = src->pnom;

    dest->lpum = src->lpum;

    dest->pim = src->pim;

    dest->mbi = be16_to_cpu(src->mbi);

    dest->pom = src->pom;

    dest->pam = src->pam;

    for (i = 0; i < ARRAY_SIZE(dest->chpid); i++) {

        dest->chpid[i] = src->chpid[i];

    }

    dest->chars = be32_to_cpu(src->chars);

}

static void copy_scsw_from_guest(SCSW *dest, const SCSW *src)

{

    dest->flags = be16_to_cpu(src->flags);

    dest->ctrl = be16_to_cpu(src->ctrl);

    dest->cpa = be32_to_cpu(src->cpa);

    dest->dstat = src->dstat;

    dest->cstat = src->cstat;

    dest->count = be16_to_cpu(src->count);

}

static void copy_schib_from_guest(SCHIB *dest, const SCHIB *src)

{

    int i;

    copy_pmcw_from_guest(&dest->pmcw, &src->pmcw);

    copy_scsw_from_guest(&dest->scsw, &src->scsw);

    dest->mba = be64_to_cpu(src->mba);

    for (i = 0; i < ARRAY_SIZE(dest->mda); i++) {

        dest->mda[i] = src->mda[i];

    }

}

int css_do_msch(SubchDev *sch, SCHIB *orig_schib)

{

    SCSW *s = &sch->curr_status.scsw;

    PMCW *p = &sch->curr_status.pmcw;

    int ret;

    SCHIB schib;

    if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_DNV)) {

        ret = 0;

        goto out;

    }

    if (s->ctrl & SCSW_STCTL_STATUS_PEND) {

        ret = -EINPROGRESS;

        goto out;

    }

    if (s->ctrl &

        (SCSW_FCTL_START_FUNC|SCSW_FCTL_HALT_FUNC|SCSW_FCTL_CLEAR_FUNC)) {

        ret = -EBUSY;

        goto out;

    }

    copy_schib_from_guest(&schib, orig_schib);

    /* Only update the program-modifiable fields. */

    p->intparm = schib.pmcw.intparm;

    p->flags &= ~(PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |

                  PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |

                  PMCW_FLAGS_MASK_MP);

    p->flags |= schib.pmcw.flags &

            (PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |

             PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |

             PMCW_FLAGS_MASK_MP);

    p->lpm = schib.pmcw.lpm;

    p->mbi = schib.pmcw.mbi;

    p->pom = schib.pmcw.pom;

    p->chars &= ~(PMCW_CHARS_MASK_MBFC | PMCW_CHARS_MASK_CSENSE);

    p->chars |= schib.pmcw.chars &

            (PMCW_CHARS_MASK_MBFC | PMCW_CHARS_MASK_CSENSE);

    sch->curr_status.mba = schib.mba;

    ret = 0;

out:

    return ret;

}

int css_do_xsch(SubchDev *sch)

{

    SCSW *s = &sch->curr_status.scsw;

    PMCW *p = &sch->curr_status.pmcw;

    int ret;

    if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {

        ret = -ENODEV;

        goto out;

    }

    if (!(s->ctrl & SCSW_CTRL_MASK_FCTL) ||

        ((s->ctrl & SCSW_CTRL_MASK_FCTL) != SCSW_FCTL_START_FUNC) ||

        (!(s->ctrl &

           (SCSW_ACTL_RESUME_PEND | SCSW_ACTL_START_PEND | SCSW_ACTL_SUSP))) ||

        (s->ctrl & SCSW_ACTL_SUBCH_ACTIVE)) {

        ret = -EINPROGRESS;

        goto out;

    }

    if (s->ctrl & SCSW_CTRL_MASK_STCTL) {

        ret = -EBUSY;

        goto out;

    }

    /* Cancel the current operation. */

    s->ctrl &= ~(SCSW_FCTL_START_FUNC |

                 SCSW_ACTL_RESUME_PEND |

                 SCSW_ACTL_START_PEND |

                 SCSW_ACTL_SUSP);

    sch->channel_prog = 0x0;

    sch->last_cmd_valid = false;

    sch->orb = NULL;

    s->dstat = 0;

    s->cstat = 0;

    ret = 0;

out:

    return ret;

}

int css_do_csch(SubchDev *sch)

{

    SCSW *s = &sch->curr_status.scsw;

    PMCW *p = &sch->curr_status.pmcw;

    int ret;

    if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {

        ret = -ENODEV;

        goto out;

    }

    /* Trigger the clear function. */

    s->ctrl &= ~(SCSW_CTRL_MASK_FCTL | SCSW_CTRL_MASK_ACTL);

    s->ctrl |= SCSW_FCTL_CLEAR_FUNC | SCSW_FCTL_CLEAR_FUNC;

    do_subchannel_work(sch);

    ret = 0;

out:

    return ret;

}

int css_do_hsch(SubchDev *sch)

{

    SCSW *s = &sch->curr_status.scsw;

    PMCW *p = &sch->curr_status.pmcw;

    int ret;

    if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {

        ret = -ENODEV;

        goto out;

    }

    if (((s->ctrl & SCSW_CTRL_MASK_STCTL) == SCSW_STCTL_STATUS_PEND) ||

        (s->ctrl & (SCSW_STCTL_PRIMARY |

                    SCSW_STCTL_SECONDARY |

                    SCSW_STCTL_ALERT))) {

        ret = -EINPROGRESS;

        goto out;

    }

    if (s->ctrl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) {

        ret = -EBUSY;

        goto out;

    }

    /* Trigger the halt function. */

    s->ctrl |= SCSW_FCTL_HALT_FUNC;

    s->ctrl &= ~SCSW_FCTL_START_FUNC;

    if (((s->ctrl & SCSW_CTRL_MASK_ACTL) ==

         (SCSW_ACTL_SUBCH_ACTIVE | SCSW_ACTL_DEVICE_ACTIVE)) &&

        ((s->ctrl & SCSW_CTRL_MASK_STCTL) == SCSW_STCTL_INTERMEDIATE)) {

        s->ctrl &= ~SCSW_STCTL_STATUS_PEND;

    }

    s->ctrl |= SCSW_ACTL_HALT_PEND;

    do_subchannel_work(sch);

    ret = 0;

out:

    return ret;

}

static void css_update_chnmon(SubchDev *sch)

{

    if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_MME)) {

        /* Not active. */

        return;

    }

    /* The counter is conveniently located at the beginning of the struct. */

    if (sch->curr_status.pmcw.chars & PMCW_CHARS_MASK_MBFC) {

        /* Format 1, per-subchannel area. */

        uint32_t count;

        count = ldl_phys(sch->curr_status.mba);

        count++;

        stl_phys(sch->curr_status.mba, count);

    } else {

        /* Format 0, global area. */

        uint32_t offset;

        uint16_t count;

        offset = sch->curr_status.pmcw.mbi << 5;

        count = lduw_phys(channel_subsys->chnmon_area + offset);

        count++;

        stw_phys(channel_subsys->chnmon_area + offset, count);

    }

}

int css_do_ssch(SubchDev *sch, ORB *orb)

{

    SCSW *s = &sch->curr_status.scsw;

    PMCW *p = &sch->curr_status.pmcw;

    int ret;

    if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {

        ret = -ENODEV;

        goto out;

    }

    if (s->ctrl & SCSW_STCTL_STATUS_PEND) {

        ret = -EINPROGRESS;

        goto out;

    }

    if (s->ctrl & (SCSW_FCTL_START_FUNC |

                   SCSW_FCTL_HALT_FUNC |

                   SCSW_FCTL_CLEAR_FUNC)) {

        ret = -EBUSY;

        goto out;

    }

    /* If monitoring is active, update counter. */

    if (channel_subsys->chnmon_active) {

        css_update_chnmon(sch);

    }

    sch->orb = orb;

    sch->channel_prog = orb->cpa;

    /* Trigger the start function. */

    s->ctrl |= (SCSW_FCTL_START_FUNC | SCSW_ACTL_START_PEND);

    s->flags &= ~SCSW_FLAGS_MASK_PNO;

    do_subchannel_work(sch);

    ret = 0;

out:

    return ret;

}

static void copy_irb_to_guest(IRB *dest, const IRB *src)

{

    int i;

    copy_scsw_to_guest(&dest->scsw, &src->scsw);

    for (i = 0; i < ARRAY_SIZE(dest->esw); i++) {

        dest->esw[i] = cpu_to_be32(src->esw[i]);

    }

    for (i = 0; i < ARRAY_SIZE(dest->ecw); i++) {

        dest->ecw[i] = cpu_to_be32(src->ecw[i]);

    }

    for (i = 0; i < ARRAY_SIZE(dest->emw); i++) {

        dest->emw[i] = cpu_to_be32(src->emw[i]);

    }

}

int css_do_tsch(SubchDev *sch, IRB *target_irb)

{

    SCSW *s = &sch->curr_status.scsw;

    PMCW *p = &sch->curr_status.pmcw;

    uint16_t stctl;

    uint16_t fctl;

    uint16_t actl;

    IRB irb;

    int ret;

    if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {

        ret = 3;

        goto out;

    }

    stctl = s->ctrl & SCSW_CTRL_MASK_STCTL;

    fctl = s->ctrl & SCSW_CTRL_MASK_FCTL;

    actl = s->ctrl & SCSW_CTRL_MASK_ACTL;

    /* Prepare the irb for the guest. */

    memset(&irb, 0, sizeof(IRB));

    /* Copy scsw from current status. */

    memcpy(&irb.scsw, s, sizeof(SCSW));

    if (stctl & SCSW_STCTL_STATUS_PEND) {

        if (s->cstat & (SCSW_CSTAT_DATA_CHECK |

                        SCSW_CSTAT_CHN_CTRL_CHK |

                        SCSW_CSTAT_INTF_CTRL_CHK)) {

            irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF;

            irb.esw[0] = 0x04804000;

        } else {

            irb.esw[0] = 0x00800000;

        }

        /* If a unit check is pending, copy sense data. */

        if ((s->dstat & SCSW_DSTAT_UNIT_CHECK) &&

            (p->chars & PMCW_CHARS_MASK_CSENSE)) {

            irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF | SCSW_FLAGS_MASK_ECTL;

            memcpy(irb.ecw, sch->sense_data, sizeof(sch->sense_data));

            irb.esw[1] = 0x01000000 | (sizeof(sch->sense_data) << 8);

        }

    }

    /* Store the irb to the guest. */

    copy_irb_to_guest(target_irb, &irb);

    /* Clear conditions on subchannel, if applicable. */

    if (stctl & SCSW_STCTL_STATUS_PEND) {

        s->ctrl &= ~SCSW_CTRL_MASK_STCTL;

        if ((stctl != (SCSW_STCTL_INTERMEDIATE | SCSW_STCTL_STATUS_PEND)) ||

            ((fctl & SCSW_FCTL_HALT_FUNC) &&

             (actl & SCSW_ACTL_SUSP))) {

            s->ctrl &= ~SCSW_CTRL_MASK_FCTL;

        }

        if (stctl != (SCSW_STCTL_INTERMEDIATE | SCSW_STCTL_STATUS_PEND)) {

            s->flags &= ~SCSW_FLAGS_MASK_PNO;

            s->ctrl &= ~(SCSW_ACTL_RESUME_PEND |

                         SCSW_ACTL_START_PEND |

                         SCSW_ACTL_HALT_PEND |

                         SCSW_ACTL_CLEAR_PEND |

                         SCSW_ACTL_SUSP);

        } else {

            if ((actl & SCSW_ACTL_SUSP) &&

                (fctl & SCSW_FCTL_START_FUNC)) {

                s->flags &= ~SCSW_FLAGS_MASK_PNO;

                if (fctl & SCSW_FCTL_HALT_FUNC) {

                    s->ctrl &= ~(SCSW_ACTL_RESUME_PEND |

                                 SCSW_ACTL_START_PEND |

                                 SCSW_ACTL_HALT_PEND |

                                 SCSW_ACTL_CLEAR_PEND |

                                 SCSW_ACTL_SUSP);

                } else {

                    s->ctrl &= ~SCSW_ACTL_RESUME_PEND;

                }

            }

        }

        /* Clear pending sense data. */

        if (p->chars & PMCW_CHARS_MASK_CSENSE) {

            memset(sch->sense_data, 0 , sizeof(sch->sense_data));

        }

    }

    ret = ((stctl & SCSW_STCTL_STATUS_PEND) == 0);

out:

    return ret;

}

static void copy_crw_to_guest(CRW *dest, const CRW *src)

{

    dest->flags = cpu_to_be16(src->flags);

    dest->rsid = cpu_to_be16(src->rsid);

}

int css_do_stcrw(CRW *crw)

{

    CrwContainer *crw_cont;

    int ret;

    crw_cont = QTAILQ_FIRST(&channel_subsys->pending_crws);

    if (crw_cont) {

        QTAILQ_REMOVE(&channel_subsys->pending_crws, crw_cont, sibling);

        copy_crw_to_guest(crw, &crw_cont->crw);

        g_free(crw_cont);

        ret = 0;

    } else {

        /* List was empty, turn crw machine checks on again. */

        memset(crw, 0, sizeof(*crw));

        channel_subsys->do_crw_mchk = true;

        ret = 1;

    }

    return ret;

}

int css_do_tpi(IOIntCode *int_code, int lowcore)

{

    /* No pending interrupts for !KVM. */

    return 0;

 }

int css_collect_chp_desc(int m, uint8_t cssid, uint8_t f_chpid, uint8_t l_chpid,

                         int rfmt, void *buf)

{

    int i, desc_size;

    uint32_t words[8];

    uint32_t chpid_type_word;

    CssImage *css;

    if (!m && !cssid) {

        css = channel_subsys->css[channel_subsys->default_cssid];

    } else {

        css = channel_subsys->css[cssid];

    }

    if (!css) {

        return 0;

    }

    desc_size = 0;

    for (i = f_chpid; i <= l_chpid; i++) {

        if (css->chpids[i].in_use) {

            chpid_type_word = 0x80000000 | (css->chpids[i].type << 8) | i;

            if (rfmt == 0) {

                words[0] = cpu_to_be32(chpid_type_word);

                words[1] = 0;

                memcpy(buf + desc_size, words, 8);

                desc_size += 8;

            } else if (rfmt == 1) {

                words[0] = cpu_to_be32(chpid_type_word);

                words[1] = 0;

                words[2] = 0;

                words[3] = 0;

                words[4] = 0;

                words[5] = 0;

                words[6] = 0;

                words[7] = 0;

                memcpy(buf + desc_size, words, 32);

                desc_size += 32;

            }

        }

    }

    return desc_size;

}

void css_do_schm(uint8_t mbk, int update, int dct, uint64_t mbo)

{

    /* dct is currently ignored (not really meaningful for our devices) */

    /* TODO: Don't ignore mbk. */

    if (update && !channel_subsys->chnmon_active) {

        /* Enable measuring. */

        channel_subsys->chnmon_area = mbo;

        channel_subsys->chnmon_active = true;

    }

    if (!update && channel_subsys->chnmon_active) {

        /* Disable measuring. */

        channel_subsys->chnmon_area = 0;

        channel_subsys->chnmon_active = false;

    }

}

int css_do_rsch(SubchDev *sch)

{

    SCSW *s = &sch->curr_status.scsw;

    PMCW *p = &sch->curr_status.pmcw;

    int ret;

    if (!(p->flags & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA))) {

        ret = -ENODEV;

        goto out;

    }