root/sys/dev/hyperv/hvs.c
/*      $NetBSD: hvs.c,v 1.7 2021/08/07 16:19:11 thorpej Exp $  */
/*      $OpenBSD: hvs.c,v 1.17 2017/08/10 17:22:48 mikeb Exp $  */

/*-
 * Copyright (c) 2009-2012,2016 Microsoft Corp.
 * Copyright (c) 2012 NetApp Inc.
 * Copyright (c) 2012 Citrix Inc.
 * Copyright (c) 2017 Mike Belopuhov <mike@esdenera.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * The OpenBSD port was done under funding by Esdenera Networks GmbH.
 */

/* #define HVS_DEBUG_IO */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: hvs.c,v 1.7 2021/08/07 16:19:11 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/buf.h>
#include <sys/bus.h>
#include <sys/kmem.h>
#include <sys/mutex.h>

#include <uvm/uvm_extern.h>

#include <dev/hyperv/vmbusvar.h>

#include <dev/scsipi/scsi_all.h>
#include <dev/scsipi/scsiconf.h>
#include <dev/scsipi/scsipi_all.h>

#define HVS_PROTO_VERSION_WIN6          0x200
#define HVS_PROTO_VERSION_WIN7          0x402
#define HVS_PROTO_VERSION_WIN8          0x501
#define HVS_PROTO_VERSION_WIN8_1        0x600
#define HVS_PROTO_VERSION_WIN10         0x602

#define HVS_MSG_IODONE                  0x01
#define HVS_MSG_DEVGONE                 0x02
#define HVS_MSG_ENUMERATE               0x0b

#define HVS_REQ_SCSIIO                  0x03
#define HVS_REQ_STARTINIT               0x07
#define HVS_REQ_FINISHINIT              0x08
#define HVS_REQ_QUERYPROTO              0x09
#define HVS_REQ_QUERYPROPS              0x0a
#define HVS_REQ_CREATEMULTICHANNELS     0x0d

struct hvs_cmd_hdr {
        uint32_t                hdr_op;
        uint32_t                hdr_flags;
        uint32_t                hdr_status;
#define cmd_op                  cmd_hdr.hdr_op
#define cmd_flags               cmd_hdr.hdr_flags
#define cmd_status              cmd_hdr.hdr_status
} __packed;

/* Negotiate version */
struct hvs_cmd_ver {
        struct hvs_cmd_hdr      cmd_hdr;
        uint16_t                cmd_ver;
        uint16_t                cmd_rev;
} __packed;

/* Query channel properties */
struct hvs_chp {
        uint16_t                chp_proto;
        uint8_t                 chp_path;
        uint8_t                 chp_target;
        uint16_t                chp_maxchan;
        uint16_t                chp_port;
        uint32_t                chp_chflags;
#define CHP_CHFLAGS_MULTI_CHANNEL       0x1
        uint32_t                chp_maxfer;
        uint64_t                chp_chanid;
} __packed;

struct hvs_cmd_chp {
        struct hvs_cmd_hdr      cmd_hdr;
        struct hvs_chp          cmd_chp;
} __packed;

#define SENSE_DATA_LEN_WIN7             18
#define SENSE_DATA_LEN                  20
#define MAX_SRB_DATA                    20

/* SCSI Request Block */
struct hvs_srb {
        uint16_t                srb_reqlen;
        uint8_t                 srb_iostatus;
        uint8_t                 srb_scsistatus;

        uint8_t                 srb_initiator;
        uint8_t                 srb_bus;
        uint8_t                 srb_target;
        uint8_t                 srb_lun;

        uint8_t                 srb_cdblen;
        uint8_t                 srb_senselen;
        uint8_t                 srb_direction;
        uint8_t                 _reserved;

        uint32_t                srb_datalen;
        uint8_t                 srb_data[MAX_SRB_DATA];
} __packed;

#define SRB_DATA_WRITE                  0
#define SRB_DATA_READ                   1
#define SRB_DATA_NONE                   2

#define SRB_STATUS_PENDING              0x00
#define SRB_STATUS_SUCCESS              0x01
#define SRB_STATUS_ABORTED              0x02
#define SRB_STATUS_ERROR                0x04
#define SRB_STATUS_INVALID_LUN          0x20
#define SRB_STATUS_QUEUE_FROZEN         0x40
#define SRB_STATUS_AUTOSENSE_VALID      0x80

#define SRB_FLAGS_QUEUE_ACTION_ENABLE           0x00000002
#define SRB_FLAGS_DISABLE_DISCONNECT            0x00000004
#define SRB_FLAGS_DISABLE_SYNCH_TRANSFER        0x00000008
#define SRB_FLAGS_BYPASS_FROZEN_QUEUE           0x00000010
#define SRB_FLAGS_DISABLE_AUTOSENSE             0x00000020
#define SRB_FLAGS_DATA_IN                       0x00000040
#define SRB_FLAGS_DATA_OUT                      0x00000080
#define SRB_FLAGS_NO_DATA_TRANSFER              0x00000000
#define SRB_FLAGS_NO_QUEUE_FREEZE               0x00000100
#define SRB_FLAGS_ADAPTER_CACHE_ENABLE          0x00000200
#define SRB_FLAGS_FREE_SENSE_BUFFER             0x00000400

struct hvs_cmd_io {
        struct hvs_cmd_hdr      cmd_hdr;
        struct hvs_srb          cmd_srb;
        /* Win8 extensions */
        uint16_t                _reserved;
        uint8_t                 cmd_qtag;
        uint8_t                 cmd_qaction;
        uint32_t                cmd_srbflags;
        uint32_t                cmd_timeout;
        uint32_t                cmd_qsortkey;
} __packed;

#define HVS_CMD_SIZE                    64

union hvs_cmd {
        struct hvs_cmd_hdr      cmd_hdr;
        struct hvs_cmd_ver      ver;
        struct hvs_cmd_chp      chp;
        struct hvs_cmd_io       io;
        uint16_t                multi_chans_cnt;
        uint8_t                 pad[HVS_CMD_SIZE];
} __packed;

#define HVS_RING_SIZE                   (20 * PAGE_SIZE)
#define HVS_MAX_CCB                     128
#define HVS_MAX_SGE                     (howmany(MAXPHYS, PAGE_SIZE) + 1)

struct hvs_softc;

struct hvs_ccb {
        struct scsipi_xfer      *ccb_xfer;  /* associated transfer */
        union hvs_cmd           *ccb_cmd;   /* associated command */
        union hvs_cmd           ccb_rsp;    /* response */
        bus_dmamap_t            ccb_dmap;   /* transfer map */
        uint64_t                ccb_rid;    /* request id */
        struct vmbus_gpa_range  *ccb_sgl;
        int                     ccb_nsge;
        void                    (*ccb_done)(struct hvs_ccb *);
        void                    *ccb_cookie;
        SIMPLEQ_ENTRY(hvs_ccb)  ccb_link;
};
SIMPLEQ_HEAD(hvs_ccb_queue, hvs_ccb);

struct hvs_config;

struct hvs_softc {
        device_t                sc_dev;
        bus_dma_tag_t           sc_dmat;

        struct vmbus_channel    *sc_chan;

        const struct hvs_config *sc_config;

        struct hvs_chp          sc_props;

        /* CCBs */
        int                     sc_nccb;
        struct hvs_ccb          *sc_ccbs;
        struct hvs_ccb_queue    sc_ccb_fq;  /* free queue */
        kmutex_t                sc_ccb_fqlck;

        int                     sc_bus;

        struct scsipi_adapter   sc_adapter;
        struct scsipi_channel   sc_channel;
        device_t                sc_scsibus;
#if notyet /* XXX subchannel */
        u_int                   sc_nchan;
        struct vmbus_channel    *sc_sel_chan[MAXCPUS];
#endif
};

static int      hvs_match(device_t, cfdata_t, void *);
static void     hvs_attach(device_t, device_t, void *);
static int      hvs_detach(device_t, int);

CFATTACH_DECL_NEW(hvs, sizeof(struct hvs_softc),
    hvs_match, hvs_attach, hvs_detach, NULL);

static void     hvs_scsipi_request(struct scsipi_channel *,
                    scsipi_adapter_req_t, void *);
static void     hvs_scsi_cmd_done(struct hvs_ccb *);
static int      hvs_start(struct hvs_softc *, struct vmbus_channel *,
                    struct hvs_ccb *);
static int      hvs_poll(struct hvs_softc *, struct vmbus_channel *,
                    struct hvs_ccb *);
static void     hvs_poll_done(struct hvs_ccb *);
static void     hvs_intr(void *);
static void     hvs_scsi_probe(void *arg);
static void     hvs_scsi_done(struct scsipi_xfer *, int);

static int      hvs_connect(struct hvs_softc *);
static void     hvs_empty_done(struct hvs_ccb *);

static int      hvs_alloc_ccbs(struct hvs_softc *);
static void     hvs_free_ccbs(struct hvs_softc *);
static struct hvs_ccb *
                hvs_get_ccb(struct hvs_softc *);
static void     hvs_put_ccb(struct hvs_softc *, struct hvs_ccb *);

static const struct hvs_config {
        uint32_t        proto_version;
        uint16_t        reqlen;
        uint8_t         senselen;
        bool            fixup_wrong_response;
        bool            upgrade_spc2_to_spc3;
        bool            use_win8ext_flags;
} hvs_config_list[] = {
        {
                .proto_version = HVS_PROTO_VERSION_WIN10,
                .reqlen = sizeof(struct hvs_cmd_io),
                .senselen = SENSE_DATA_LEN,
                .fixup_wrong_response = false,
                .upgrade_spc2_to_spc3 = false,
                .use_win8ext_flags = true,
        },
        {
                .proto_version = HVS_PROTO_VERSION_WIN8_1,
                .reqlen = sizeof(struct hvs_cmd_io),
                .senselen = SENSE_DATA_LEN,
                .fixup_wrong_response = true,
                .upgrade_spc2_to_spc3 = true,
                .use_win8ext_flags = true,
        },
        {
                .proto_version = HVS_PROTO_VERSION_WIN8,
                .reqlen = sizeof(struct hvs_cmd_io),
                .senselen = SENSE_DATA_LEN,
                .fixup_wrong_response = true,
                .upgrade_spc2_to_spc3 = true,
                .use_win8ext_flags = true,
        },
        {
                .proto_version = HVS_PROTO_VERSION_WIN7,
                .reqlen = offsetof(struct hvs_cmd_io, _reserved),
                .senselen = SENSE_DATA_LEN_WIN7,
                .fixup_wrong_response = true,
                .upgrade_spc2_to_spc3 = false,
                .use_win8ext_flags = false,
        },
        {
                .proto_version = HVS_PROTO_VERSION_WIN6,
                .reqlen = offsetof(struct hvs_cmd_io, _reserved),
                .senselen = SENSE_DATA_LEN_WIN7,
                .fixup_wrong_response = false,
                .upgrade_spc2_to_spc3 = false,
                .use_win8ext_flags = false,
        },
};

#if notyet /* XXX subchannel */
static int hvs_chan_cnt;
#endif

static int
hvs_match(device_t parent, cfdata_t cf, void *aux)
{
        struct vmbus_attach_args *aa = aux;

        if (memcmp(aa->aa_type, &hyperv_guid_ide, sizeof(*aa->aa_type)) != 0 &&
            memcmp(aa->aa_type, &hyperv_guid_scsi, sizeof(*aa->aa_type)) != 0)
                return 0;
        return 1;
}

static void
hvs_attach(device_t parent, device_t self, void *aux)
{
        extern struct cfdata cfdata[];
        struct hvs_softc *sc = device_private(self);
        struct vmbus_attach_args *aa = aux;
        struct scsipi_adapter *adapt = &sc->sc_adapter;
        struct scsipi_channel *chan = &sc->sc_channel;
        const char *bus;
        bool is_scsi;

        sc->sc_dev = self;
        sc->sc_chan = aa->aa_chan;
        sc->sc_dmat = sc->sc_chan->ch_sc->sc_dmat;
#if notyet /* XXX subchannel */
        sc->sc_nchan = 1;
        sc->sc_sel_chan[0] = sc->sc_chan;
#endif

        if (memcmp(aa->aa_type, &hyperv_guid_scsi, sizeof(*aa->aa_type)) == 0) {
                is_scsi = true;
                bus = "SCSI";
        } else {
                is_scsi = false;
                bus = "IDE";
        }

        aprint_naive("\n");
        aprint_normal(": Hyper-V StorVSC %s\n", bus);

        if (vmbus_channel_setdeferred(sc->sc_chan, device_xname(self))) {
                aprint_error_dev(self,
                    "failed to create the interrupt thread\n");
                return;
        }

        if (vmbus_channel_open(sc->sc_chan, HVS_RING_SIZE, &sc->sc_props,
            sizeof(sc->sc_props), hvs_intr, sc)) {
                aprint_error_dev(self, "failed to open channel\n");
                return;
        }

        if (hvs_alloc_ccbs(sc))
                return;

        if (hvs_connect(sc))
                return;

        aprint_normal_dev(self, "protocol %u.%u\n",
            (sc->sc_config->proto_version >> 8) & 0xff,
            sc->sc_config->proto_version & 0xff);

        adapt = &sc->sc_adapter;
        adapt->adapt_dev = self;
        adapt->adapt_nchannels = 1;
        adapt->adapt_openings = sc->sc_nccb;
        adapt->adapt_max_periph = adapt->adapt_openings;
        adapt->adapt_request = hvs_scsipi_request;
        adapt->adapt_minphys = minphys;
        adapt->adapt_flags = SCSIPI_ADAPT_MPSAFE;

        chan = &sc->sc_channel;
        chan->chan_adapter = adapt;
        chan->chan_bustype = &scsi_bustype;     /* XXX IDE/ATAPI */
        chan->chan_channel = 0;
        chan->chan_ntargets = 2;
        chan->chan_nluns = is_scsi ? 64 : 1;
        chan->chan_id = 0;
        chan->chan_flags = SCSIPI_CHAN_NOSETTLE;
        chan->chan_defquirks |= PQUIRK_ONLYBIG;

        sc->sc_scsibus = config_found(self, &sc->sc_channel, scsiprint,
            CFARGS_NONE);

        /*
         * If the driver has successfully attached to an IDE device,
         * we need to make sure that the same disk is not available to
         * the system via pciide(4) or piixide(4) causing DUID conflicts
         * and preventing system from booting.
         */
        if (!is_scsi && sc->sc_scsibus != NULL) {
                static const char *disable_devices[] = {
                        "wd",
                };
                size_t j;

                for (j = 0; j < __arraycount(disable_devices); j++) {
                        const char *dev = disable_devices[j];
                        size_t len = strlen(dev);
                        int devno;

                        for (devno = 0; cfdata[devno].cf_name != NULL; devno++) {
                                cfdata_t cf = &cfdata[devno];

                                if (strlen(cf->cf_name) != len ||
                                    strncasecmp(dev, cf->cf_name, len) != 0 ||
                                    cf->cf_fstate != FSTATE_STAR)
                                        continue;

                                cf->cf_fstate = FSTATE_DSTAR;
                        }
                }
        }
}

static int
hvs_detach(device_t self, int flags)
{

        /* XXX detach */

        return 0;
}

#define XS2DMA(xs) \
    ((((xs)->xs_control & XS_CTL_DATA_IN) ? BUS_DMA_READ : BUS_DMA_WRITE) | \
    (((xs)->xs_control & XS_CTL_NOSLEEP) ? BUS_DMA_NOWAIT : BUS_DMA_WAITOK) | \
    BUS_DMA_STREAMING)

#define XS2DMAPRE(xs) (((xs)->xs_control & XS_CTL_DATA_IN) ? \
    BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE)

#define XS2DMAPOST(xs) (((xs)->xs_control & XS_CTL_DATA_IN) ? \
    BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE)

static void
hvs_scsipi_request(struct scsipi_channel *chan, scsipi_adapter_req_t request,
    void *arg)
{
        struct scsipi_adapter *adapt = chan->chan_adapter;
        struct hvs_softc *sc = device_private(adapt->adapt_dev);
        struct scsipi_xfer *xs;
        struct scsipi_xfer_mode *xm;
        struct scsipi_periph *periph;
        struct hvs_ccb *ccb;
        union hvs_cmd cmd;
        struct hvs_cmd_io *io = &cmd.io;
        struct hvs_srb *srb = &io->cmd_srb;
        int i, error;

        switch (request) {
        default:
                device_printf(sc->sc_dev,
                    "%s: unhandled request %u\n", __func__, request);
                return;

        case ADAPTER_REQ_GROW_RESOURCES:
                /* Not supported. */
                return;

        case ADAPTER_REQ_SET_XFER_MODE:
                xm = arg;
                xm->xm_mode = PERIPH_CAP_TQING;
                xm->xm_period = 0;
                xm->xm_offset = 0;
                scsipi_async_event(chan, ASYNC_EVENT_XFER_MODE, xm);
                return;

        case ADAPTER_REQ_RUN_XFER:
                break;
        }

        xs = arg;

        if (xs->cmdlen > MAX_SRB_DATA) {
                device_printf(sc->sc_dev, "CDB is too big: %d\n",
                    xs->cmdlen);
                memset(&xs->sense, 0, sizeof(xs->sense));
                xs->sense.scsi_sense.response_code =
                    SSD_RCODE_VALID | SSD_RCODE_CURRENT;
                xs->sense.scsi_sense.flags = SSD_ILI;
                xs->sense.scsi_sense.asc = 0x20;
                hvs_scsi_done(xs, XS_SENSE);
                return;
        }

        ccb = hvs_get_ccb(sc);
        if (ccb == NULL) {
                device_printf(sc->sc_dev, "failed to allocate ccb\n");
                hvs_scsi_done(xs, XS_RESOURCE_SHORTAGE);
                return;
        }

        periph = xs->xs_periph;

        memset(&cmd, 0, sizeof(cmd));

        srb->srb_initiator = chan->chan_id;
        srb->srb_bus = sc->sc_bus;
        srb->srb_target = periph->periph_target - 1;
        srb->srb_lun = periph->periph_lun;
        srb->srb_cdblen = xs->cmdlen;
        memcpy(srb->srb_data, xs->cmd, xs->cmdlen);

        if (sc->sc_config->use_win8ext_flags) {
                io->cmd_timeout = 60;
                SET(io->cmd_srbflags, SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
        }

        switch (xs->xs_control & (XS_CTL_DATA_IN | XS_CTL_DATA_OUT)) {
        case XS_CTL_DATA_IN:
                srb->srb_direction = SRB_DATA_READ;
                if (sc->sc_config->use_win8ext_flags)
                        SET(io->cmd_srbflags, SRB_FLAGS_DATA_IN);
                break;
        case XS_CTL_DATA_OUT:
                srb->srb_direction = SRB_DATA_WRITE;
                if (sc->sc_config->use_win8ext_flags)
                        SET(io->cmd_srbflags, SRB_FLAGS_DATA_OUT);
                break;
        default:
                srb->srb_direction = SRB_DATA_NONE;
                if (sc->sc_config->use_win8ext_flags)
                        SET(io->cmd_srbflags, SRB_FLAGS_NO_DATA_TRANSFER);
                break;
        }

        srb->srb_datalen = xs->datalen;
        srb->srb_reqlen = sc->sc_config->reqlen;
        srb->srb_senselen = sc->sc_config->senselen;

        cmd.cmd_op = HVS_REQ_SCSIIO;
        cmd.cmd_flags = VMBUS_CHANPKT_FLAG_RC;

        if (xs->datalen > 0) {
                error = bus_dmamap_load(sc->sc_dmat, ccb->ccb_dmap, xs->data,
                    xs->datalen, NULL, XS2DMA(xs));
                if (error) {
                        device_printf(sc->sc_dev,
                            "failed to load %d bytes (%d)\n", xs->datalen,
                            error);
                        hvs_put_ccb(sc, ccb);
                        hvs_scsi_done(xs, (error == ENOMEM || error == EAGAIN) ?
                            XS_RESOURCE_SHORTAGE : XS_DRIVER_STUFFUP);
                        return;
                }
                bus_dmamap_sync(sc->sc_dmat, ccb->ccb_dmap, 0, xs->datalen,
                    XS2DMAPRE(xs));

                ccb->ccb_sgl->gpa_len = xs->datalen;
                ccb->ccb_sgl->gpa_ofs = (vaddr_t)xs->data & PAGE_MASK;
                for (i = 0; i < ccb->ccb_dmap->dm_nsegs; i++)
                        ccb->ccb_sgl->gpa_page[i] =
                            atop(ccb->ccb_dmap->dm_segs[i].ds_addr);
                ccb->ccb_nsge = ccb->ccb_dmap->dm_nsegs;
        } else
                ccb->ccb_nsge = 0;

        ccb->ccb_xfer = xs;
        ccb->ccb_cmd = &cmd;
        ccb->ccb_done = hvs_scsi_cmd_done;

#ifdef HVS_DEBUG_IO
        printf("%s: %u.%u: rid %"PRIu64" opcode %#x control %#x datalen %d\n",
            device_xname(sc->sc_dev), periph->periph_target, periph->periph_lun,
            ccb->ccb_rid, xs->cmd->opcode, xs->xs_control, xs->datalen);
#endif

        if (xs->xs_control & XS_CTL_POLL)
                error = hvs_poll(sc, sc->sc_chan, ccb);
        else
                error = hvs_start(sc, sc->sc_chan, ccb);
        if (error) {
                hvs_put_ccb(sc, ccb);
                hvs_scsi_done(xs, (error == ENOMEM || error == EAGAIN) ?
                    XS_RESOURCE_SHORTAGE : XS_DRIVER_STUFFUP);
        }
}

static int
hvs_start(struct hvs_softc *sc, struct vmbus_channel *chan, struct hvs_ccb *ccb)
{
        union hvs_cmd *cmd = ccb->ccb_cmd;
        int error;

        ccb->ccb_cmd = NULL;

        if (ccb->ccb_nsge > 0) {
                error = vmbus_channel_send_prpl(chan, ccb->ccb_sgl,
                    ccb->ccb_nsge, cmd, HVS_CMD_SIZE, ccb->ccb_rid);
                if (error) {
                        device_printf(sc->sc_dev,
                            "failed to submit operation %x via prpl\n",
                            cmd->cmd_op);
                        bus_dmamap_unload(sc->sc_dmat, ccb->ccb_dmap);
                }
        } else {
                error = vmbus_channel_send(chan, cmd, HVS_CMD_SIZE,
                    ccb->ccb_rid, VMBUS_CHANPKT_TYPE_INBAND,
                    VMBUS_CHANPKT_FLAG_RC);
                if (error)
                        device_printf(sc->sc_dev,
                            "failed to submit operation %x\n", cmd->cmd_op);
        }

        return error;
}

static void
hvs_poll_done(struct hvs_ccb *ccb)
{
        int *rv = ccb->ccb_cookie;

        if (ccb->ccb_cmd) {
                memcpy(&ccb->ccb_rsp, ccb->ccb_cmd, HVS_CMD_SIZE);
                ccb->ccb_cmd = &ccb->ccb_rsp;
        } else
                memset(&ccb->ccb_rsp, 0, HVS_CMD_SIZE);

        *rv = 0;
}

static int
hvs_poll(struct hvs_softc *sc, struct vmbus_channel *chan, struct hvs_ccb *ccb)
{
        void (*done)(struct hvs_ccb *);
        void *cookie;
        int s, rv = 1;

        done = ccb->ccb_done;
        cookie = ccb->ccb_cookie;

        ccb->ccb_done = hvs_poll_done;
        ccb->ccb_cookie = &rv;

        if (hvs_start(sc, chan, ccb)) {
                ccb->ccb_cookie = cookie;
                ccb->ccb_done = done;
                return -1;
        }

        while (rv == 1) {
                delay(10);
                s = splbio();
                hvs_intr(sc);
                splx(s);
        }

        ccb->ccb_cookie = cookie;
        ccb->ccb_done = done;
        ccb->ccb_done(ccb);

        return 0;
}

static void
hvs_intr(void *xsc)
{
        struct hvs_softc *sc = xsc;
        struct hvs_ccb *ccb;
        union hvs_cmd cmd;
        uint64_t rid;
        uint32_t rlen;
        int error;

        for (;;) {
                error = vmbus_channel_recv(sc->sc_chan, &cmd, sizeof(cmd),
                    &rlen, &rid, 0);
                switch (error) {
                case 0:
                        break;
                case EAGAIN:
                        /* No more messages to process */
                        return;
                default:
                        device_printf(sc->sc_dev,
                            "error %d while receiving a reply\n", error);
                        return;
                }
                if (rlen != sizeof(cmd)) {
                        device_printf(sc->sc_dev, "short read: %u\n", rlen);
                        return;
                }

#ifdef HVS_DEBUG_IO
                printf("%s: rid %"PRIu64" operation %u flags %#x status %#x\n",
                    device_xname(sc->sc_dev), rid, cmd.cmd_op, cmd.cmd_flags,
                    cmd.cmd_status);
#endif

                switch (cmd.cmd_op) {
                case HVS_MSG_IODONE:
                        if (rid >= sc->sc_nccb) {
                                device_printf(sc->sc_dev,
                                    "invalid response %#"PRIx64"\n", rid);
                                continue;
                        }
                        ccb = &sc->sc_ccbs[rid];
                        ccb->ccb_cmd = &cmd;
                        ccb->ccb_done(ccb);
                        break;
                case HVS_MSG_ENUMERATE:
                        hvs_scsi_probe(sc);
                        break;
                default:
                        device_printf(sc->sc_dev,
                            "operation %u is not implemented\n", cmd.cmd_op);
                        break;
                }
        }
}

static int
is_inquiry_valid(struct scsipi_inquiry_data *inq)
{

        if ((inq->device & SID_TYPE) == T_NODEVICE)
                return 0;
        if ((inq->device & SID_QUAL) == SID_QUAL_LU_NOT_SUPP)
                return 0;
        return 1;
}

static void
fixup_inquiry(struct scsipi_xfer *xs, struct hvs_srb *srb)
{
        struct scsipi_periph *periph = xs->xs_periph;
        struct scsipi_channel *chan = periph->periph_channel;
        struct scsipi_adapter *adapt = chan->chan_adapter;
        struct hvs_softc *sc = device_private(adapt->adapt_dev);
        struct scsipi_inquiry_data *inq = (void *)xs->data;
        int datalen, resplen;
        char vendor[8];

        resplen = srb->srb_datalen >= 5 ? inq->additional_length + 5 : 0;
        datalen = MIN(resplen, srb->srb_datalen);

        /* Fixup wrong response from WS2012 */
        if (sc->sc_config->fixup_wrong_response &&
            !is_inquiry_valid(inq) && datalen >= 4 &&
            (inq->version == 0 || inq->response_format == 0)) {
                inq->version = 0x05; /* SPC-3 */
                inq->response_format = SID_FORMAT_ISO;
        } else if (datalen >= SCSIPI_INQUIRY_LENGTH_SCSI2) {
                /*
                 * Upgrade SPC2 to SPC3 if host is Win8 or WS2012 R2
                 * to support UNMAP feature.
                 */
                strnvisx(vendor, sizeof(vendor), inq->vendor, sizeof(vendor),
                    VIS_TRIM|VIS_SAFE|VIS_OCTAL);
                if (sc->sc_config->upgrade_spc2_to_spc3 &&
                    (inq->version & SID_ANSII) == 0x04 /* SPC-2 */ &&
                    !strncmp(vendor, "Msft", 4))
                        inq->version = 0x05; /* SPC-3 */
        }
}

static void
hvs_scsi_cmd_done(struct hvs_ccb *ccb)
{
        struct scsipi_xfer *xs = ccb->ccb_xfer;
        struct scsipi_periph *periph = xs->xs_periph;
        struct scsipi_channel *chan = periph->periph_channel;
        struct scsipi_adapter *adapt = chan->chan_adapter;
        struct hvs_softc *sc = device_private(adapt->adapt_dev);
        union hvs_cmd *cmd = ccb->ccb_cmd;
        struct hvs_srb *srb;
        bus_dmamap_t map;
        int error;

        map = ccb->ccb_dmap;
        bus_dmamap_sync(sc->sc_dmat, map, 0, map->dm_mapsize, XS2DMAPOST(xs));
        bus_dmamap_unload(sc->sc_dmat, map);

        xs = ccb->ccb_xfer;
        srb = &cmd->io.cmd_srb;

        xs->status = srb->srb_scsistatus & 0xff;

        switch (xs->status) {
        case SCSI_OK:
                if ((srb->srb_iostatus & ~(SRB_STATUS_AUTOSENSE_VALID |
                    SRB_STATUS_QUEUE_FROZEN)) != SRB_STATUS_SUCCESS)
                        error = XS_SELTIMEOUT;
                else
                        error = XS_NOERROR;
                break;
        case SCSI_BUSY:
        case SCSI_QUEUE_FULL:
                device_printf(sc->sc_dev, "status %#x iostatus %#x (busy)\n",
                    srb->srb_scsistatus, srb->srb_iostatus);
                error = XS_BUSY;
                break;
        case SCSI_CHECK:
                if (srb->srb_iostatus & SRB_STATUS_AUTOSENSE_VALID) {
                        memcpy(&xs->sense, srb->srb_data,
                            MIN(sizeof(xs->sense), srb->srb_senselen));
                        error = XS_SENSE;
                        break;
                }
                /* FALLTHROUGH */
        default:
                error = XS_DRIVER_STUFFUP;
                break;
        }

        if (error == XS_NOERROR) {
                if (xs->cmd->opcode == INQUIRY)
                        fixup_inquiry(xs, srb);
                else if (srb->srb_direction != SRB_DATA_NONE)
                        xs->resid = xs->datalen - srb->srb_datalen;
        }

        hvs_put_ccb(sc, ccb);
        hvs_scsi_done(xs, error);
}

static void
hvs_scsi_probe(void *arg)
{
        struct hvs_softc *sc = arg;

        if (sc->sc_scsibus != NULL)
                scsi_probe_bus(device_private(sc->sc_scsibus), -1, -1);
}

static void
hvs_scsi_done(struct scsipi_xfer *xs, int error)
{

        xs->error = error;
        scsipi_done(xs);
}

static int
hvs_connect(struct hvs_softc *sc)
{
        union hvs_cmd ucmd;
        struct hvs_cmd_ver *cmd;
        struct hvs_chp *chp;
        struct hvs_ccb *ccb;
#if notyet /* XXX subchannel */
        struct vmbus_softc *vsc;
        struct vmbus_channel **subchan;
        uint32_t version;
        uint16_t max_subch, req_subch;
        bool support_multichannel = false;
#endif
        int i;

        ccb = hvs_get_ccb(sc);
        if (ccb == NULL) {
                aprint_error_dev(sc->sc_dev, "failed to allocate ccb\n");
                return -1;
        }

        ccb->ccb_done = hvs_empty_done;

        cmd = (struct hvs_cmd_ver *)&ucmd;

        /*
         * Begin initialization
         */

        memset(&ucmd, 0, sizeof(ucmd));

        cmd->cmd_op = HVS_REQ_STARTINIT;
        cmd->cmd_flags = VMBUS_CHANPKT_FLAG_RC;

        ccb->ccb_cmd = &ucmd;
        if (hvs_poll(sc, sc->sc_chan, ccb)) {
                aprint_error_dev(sc->sc_dev,
                    "failed to send initialization command\n");
                goto error;
        }
        if (ccb->ccb_rsp.cmd_status != 0) {
                aprint_error_dev(sc->sc_dev,
                    "failed to initialize, status %#x\n",
                    ccb->ccb_rsp.cmd_status);
                goto error;
        }

        /*
         * Negotiate protocol version
         */

        memset(&ucmd, 0, sizeof(ucmd));

        cmd->cmd_op = HVS_REQ_QUERYPROTO;
        cmd->cmd_flags = VMBUS_CHANPKT_FLAG_RC;

        for (i = 0; i < __arraycount(hvs_config_list); i++) {
                cmd->cmd_ver = hvs_config_list[i].proto_version;

                ccb->ccb_cmd = &ucmd;
                if (hvs_poll(sc, sc->sc_chan, ccb)) {
                        aprint_error_dev(sc->sc_dev,
                            "failed to send protocol query\n");
                        goto error;
                }
                if (ccb->ccb_rsp.cmd_status == 0) {
                        sc->sc_config = &hvs_config_list[i];
                        break;
                }
        }
        if (sc->sc_config == NULL) {
                aprint_error_dev(sc->sc_dev,
                    "failed to negotiate protocol version\n");
                goto error;
        }

        /*
         * Query channel properties
         */

        memset(&ucmd, 0, sizeof(ucmd));

        cmd->cmd_op = HVS_REQ_QUERYPROPS;
        cmd->cmd_flags = VMBUS_CHANPKT_FLAG_RC;

        ccb->ccb_cmd = &ucmd;
        if (hvs_poll(sc, sc->sc_chan, ccb)) {
                aprint_error_dev(sc->sc_dev,
                    "failed to send channel properties query\n");
                goto error;
        }
        if (ccb->ccb_rsp.cmd_op != HVS_MSG_IODONE ||
            ccb->ccb_rsp.cmd_status != 0) {
                aprint_error_dev(sc->sc_dev,
                    "failed to obtain channel properties, status %#x\n",
                    ccb->ccb_rsp.cmd_status);
                goto error;
        }
        chp = &ccb->ccb_rsp.chp.cmd_chp;

        DPRINTF("%s: proto %#x path %u target %u maxchan %u port %u "
            "chflags %#x maxfer %u chanid %#"PRIx64"\n",
            device_xname(sc->sc_dev), chp->chp_proto, chp->chp_path,
            chp->chp_target, chp->chp_maxchan, chp->chp_port,
            chp->chp_chflags, chp->chp_maxfer, chp->chp_chanid);

#if notyet /* XXX subchannel */
        max_subch = chp->chp_maxchan;
        if (hvs_chan_cnt > 0 && hvs_chan_cnt < (max_subch + 1))
                max_subch = hvs_chan_cnt - 1;

        /* multi-channels feature is supported by WIN8 and above version */
        version = sc->sc_chan->ch_sc->sc_proto;
        if (version != VMBUS_VERSION_WIN7 && version != VMBUS_VERSION_WS2008 &&
            ISSET(chp->chp_chflags, CHP_CHFLAGS_MULTI_CHANNEL))
                support_multichannel = true;
#endif

        /* XXX */
        sc->sc_bus = chp->chp_path;
        sc->sc_channel.chan_id = chp->chp_target;

        /*
         * Finish initialization
         */

        memset(&ucmd, 0, sizeof(ucmd));

        cmd->cmd_op = HVS_REQ_FINISHINIT;
        cmd->cmd_flags = VMBUS_CHANPKT_FLAG_RC;

        ccb->ccb_cmd = &ucmd;
        if (hvs_poll(sc, sc->sc_chan, ccb)) {
                aprint_error_dev(sc->sc_dev,
                    "failed to send initialization finish\n");
                goto error;
        }
        if (ccb->ccb_rsp.cmd_op != HVS_MSG_IODONE ||
            ccb->ccb_rsp.cmd_status != 0) {
                aprint_error_dev(sc->sc_dev,
                    "failed to finish initialization, status %#x\n",
                    ccb->ccb_rsp.cmd_status);
                goto error;
        }

#if notyet /* XXX subchannel */
        if (support_multichannel && max_subch > 0 && ncpu > 1) {
                req_subch = MIN(max_subch, ncpu - 1);

                memset(&ucmd, 0, sizeof(ucmd));

                cmd->cmd_op = HVS_REQ_CREATEMULTICHANNELS;
                cmd->cmd_flags = VMBUS_CHANPKT_FLAG_RC;
                cmd->u.multi_chans_cnt = req_subch;

                ccb->ccb_cmd = &ucmd;
                if (hvs_poll(sc, sc->sc_chan, ccb)) {
                        aprint_error_dev(sc->sc_dev,
                            "failed to send create multi-channel\n");
                        goto out;
                }
                if (ccb->ccb_rsp.cmd_op != HVS_MSG_IODONE ||
                    ccb->ccb_rsp.cmd_status != 0) {
                        aprint_error_dev(sc->sc_dev,
                            "failed to create multi-channel, status %#x\n",
                            ccb->ccb_rsp.cmd_status);
                        goto out;
                }

                sc->sc_nchan = req_subch + 1;
                subchan = vmbus_subchan_get(sc->sc_chan, req_subch);
                for (i = 0; i < req_subch; i++)
                        hsv_subchan_attach(sc, subchan[i]);
                vmbus_subchan_rel(subchan, req_subch);
                aprint_normal_dev(sc->sc_dev, "using %u channels\n",
                    sc->sc_nchan);
        }
out:
#endif
        hvs_put_ccb(sc, ccb);
        return 0;

error:
        hvs_put_ccb(sc, ccb);
        return -1;
}

static void
hvs_empty_done(struct hvs_ccb *ccb)
{
        /* nothing */
}

static int
hvs_alloc_ccbs(struct hvs_softc *sc)
{
        const int dmaflags = cold ? BUS_DMA_NOWAIT : BUS_DMA_WAITOK;
        int i, error;

        SIMPLEQ_INIT(&sc->sc_ccb_fq);
        mutex_init(&sc->sc_ccb_fqlck, MUTEX_DEFAULT, IPL_BIO);

        sc->sc_nccb = HVS_MAX_CCB;
        sc->sc_ccbs = kmem_zalloc(sc->sc_nccb * sizeof(struct hvs_ccb),
            KM_SLEEP);

        for (i = 0; i < sc->sc_nccb; i++) {
                error = bus_dmamap_create(sc->sc_dmat, MAXPHYS, HVS_MAX_SGE,
                    PAGE_SIZE, PAGE_SIZE, dmaflags, &sc->sc_ccbs[i].ccb_dmap);
                if (error) {
                        aprint_error_dev(sc->sc_dev,
                            "failed to create a CCB memory map (%d)\n", error);
                        goto errout;
                }

                sc->sc_ccbs[i].ccb_sgl = kmem_zalloc(
                    sizeof(struct vmbus_gpa_range) * (HVS_MAX_SGE + 1),
                    KM_SLEEP);
                sc->sc_ccbs[i].ccb_rid = i;
                hvs_put_ccb(sc, &sc->sc_ccbs[i]);
        }

        return 0;

 errout:
        hvs_free_ccbs(sc);
        return -1;
}

static void
hvs_free_ccbs(struct hvs_softc *sc)
{
        struct hvs_ccb *ccb;
        int i;

        for (i = 0; i < sc->sc_nccb; i++) {
                ccb = &sc->sc_ccbs[i];
                if (ccb->ccb_dmap == NULL)
                        continue;

                bus_dmamap_sync(sc->sc_dmat, ccb->ccb_dmap,
                    0, ccb->ccb_dmap->dm_mapsize,
                    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
                bus_dmamap_unload(sc->sc_dmat, ccb->ccb_dmap);
                bus_dmamap_destroy(sc->sc_dmat, ccb->ccb_dmap);

                kmem_free(ccb->ccb_sgl,
                    sizeof(struct vmbus_gpa_range) * (HVS_MAX_SGE + 1));
        }

        kmem_free(sc->sc_ccbs, sc->sc_nccb * sizeof(struct hvs_ccb));
        sc->sc_ccbs = NULL;
        sc->sc_nccb = 0;
}

static struct hvs_ccb *
hvs_get_ccb(struct hvs_softc *sc)
{
        struct hvs_ccb *ccb;

        mutex_enter(&sc->sc_ccb_fqlck);
        ccb = SIMPLEQ_FIRST(&sc->sc_ccb_fq);
        if (ccb != NULL)
                SIMPLEQ_REMOVE_HEAD(&sc->sc_ccb_fq, ccb_link);
        mutex_exit(&sc->sc_ccb_fqlck);

        return ccb;
}

static void
hvs_put_ccb(struct hvs_softc *sc, struct hvs_ccb *ccb)
{

        ccb->ccb_cmd = NULL;
        ccb->ccb_xfer = NULL;
        ccb->ccb_done = NULL;
        ccb->ccb_cookie = NULL;
        ccb->ccb_nsge = 0;

        mutex_enter(&sc->sc_ccb_fqlck);
        SIMPLEQ_INSERT_HEAD(&sc->sc_ccb_fq, ccb, ccb_link);
        mutex_exit(&sc->sc_ccb_fqlck);
}