[Qemu-devel] [PATCH 5/5] [scsi-bsg]: Add initial support for BSG based SCSIDeviceInfo

[Nicholas A. Bellinger]

From: Nicholas Bellinger <address@hidden>

This patch adds initial support for using the Linux BSG interface with 
write/read vectored
AIO as a QEMU backstore (SCSIDeviceInfo) with hw/scsi-bus.c compatible HBA 
emulation.

So far it has been tested with x86_64 host and guest using hw/megasas.c and 
TCM_Loop LLD
Port LUNs.  Because this path uses struct iovec for struct 
sg_io_v4->d[out,in]_xferp payloads,
which currently requires a patch to linux/block/bsg.c:bsg_map_hdr() in order to 
setup the
user -> kernel iovecs.  This also will only currently work with paired 
user/kernel
(eg: 64bit user / 64bit kernel) because of different pointer sizes in struct 
iovec->iov_base.

There are also two FIXMEs in hw/scsi-bsg.c:bsg_generic_initfn() related to 
extraction of
SCSI LUN and device type values using BSG and required by QEMU-KVM.

Signed-off-by: Nicholas A. Bellinger <address@hidden>
---
 Makefile.objs |    2 +-
 hw/scsi-bsg.c |  588 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 589 insertions(+), 1 deletions(-)
 create mode 100644 hw/scsi-bsg.c

diff --git a/Makefile.objs b/Makefile.objs
index 188d617..c4fcb72 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -197,7 +197,7 @@ hw-obj-$(CONFIG_IDE_CMD646) += ide/cmd646.o
 hw-obj-$(CONFIG_IDE_MACIO) += ide/macio.o
 
 # SCSI layer
-hw-obj-y += scsi-disk.o scsi-generic.o
+hw-obj-y += scsi-disk.o scsi-generic.o scsi-bsg.o
 hw-obj-y += lsi53c895a.o megasas.o
 hw-obj-$(CONFIG_ESP) += esp.o
 
diff --git a/hw/scsi-bsg.c b/hw/scsi-bsg.c
new file mode 100644
index 0000000..fc76b76
--- /dev/null
+++ b/hw/scsi-bsg.c
@@ -0,0 +1,588 @@
+/*
+ * block layer implementation of the sg v4 interface for Linux hosts
+ *
+ * Copyright (c) 2010 Rising Tide Systems
+ * Written by Nicholas A. Bellinger <address@hidden>
+ *
+ * Based on hw/scsi-generic code by Laurent Vivier, Paul Brook, and Fabrice 
Bellard
+ *
+ * This code is licenced under the LGPL.
+ */
+
+#include "qemu-common.h"
+#include "qemu-error.h"
+#include "block.h"
+#include "scsi.h"
+#include "dma.h"
+#include "block/raw-posix-aio.h"
+
+#ifdef __linux__
+
+#define DEBUG_BSG
+#undef DEBUG_BSG_IO
+#undef DEBUG_BSG_MAP
+
+#ifdef DEBUG_BSG
+#define DPRINTF(fmt, ...) \
+do { printf("scsi-bsg: " fmt , ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) do {} while(0)
+#endif
+
+#define BADF(fmt, ...) \
+do { fprintf(stderr, "scsi-bsg: " fmt , ## __VA_ARGS__); } while (0)
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/epoll.h>
+#include <unistd.h>
+#include <scsi/sg.h>
+#include <linux/bsg.h>
+#include "scsi-defs.h"
+
+#define SCSI_SENSE_BUF_SIZE 96
+
+#define SG_ERR_DRIVER_TIMEOUT 0x06
+#define SG_ERR_DRIVER_SENSE 0x08
+
+#ifndef MAX_UINT
+#define MAX_UINT ((unsigned int)-1)
+#endif
+
+typedef struct SCSIBSGState SCSIBSGState;
+
+typedef struct SCSIBSGReq {
+    SCSIRequest req;
+    uint8_t *buf;
+    int buflen;
+    QEMUIOVector iov;
+    QEMUIOVector aio_iov;
+    struct sg_io_v4 bsg_hdr;
+} SCSIBSGReq;
+
+struct SCSIBSGState {
+    SCSIDevice qdev;
+    BlockDriverState *bs;
+    int lun;
+    int driver_status;
+    uint8_t sensebuf[SCSI_SENSE_BUF_SIZE];
+    uint8_t senselen;
+};
+
+static int bsg_read(int fd, void *p_read, int to_read)
+{
+    int err;
+
+    while (to_read > 0) {
+        err = read(fd, p_read, to_read);
+        if (err >= 0) {
+            to_read -= err;
+            p_read += err;
+        } else if (errno == EINTR)
+            continue;
+        else {
+            printf("bsg device %d read failed, errno: %d\n",
+                    fd, errno);
+            return errno;
+        }
+    }
+    return 0;
+}
+
+static SCSIBSGReq *bsg_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun)
+{
+    SCSIRequest *req;
+    SCSIBSGReq *r;
+
+    req = scsi_req_alloc(sizeof(SCSIBSGReq), d, tag, lun);
+    r = DO_UPCAST(SCSIBSGReq, req, req);
+    qemu_iovec_init(&r->iov, 1);
+    qemu_iovec_init(&r->aio_iov, 1);
+    return r;
+}
+
+static void bsg_remove_request(SCSIBSGReq *r)
+{
+    qemu_free(r->buf);
+    qemu_iovec_destroy(&r->iov);
+    qemu_iovec_destroy(&r->aio_iov);
+    scsi_req_free(&r->req);
+}
+
+static void bsg_command_complete(void *opaque, int ret)
+{
+    SCSIBSGReq *r = (SCSIBSGReq *)opaque;
+    SCSIBSGState *s = DO_UPCAST(SCSIBSGState, qdev, r->req.dev);
+
+    s->driver_status = r->bsg_hdr.driver_status;
+    if (s->driver_status)
+        s->senselen = SCSI_SENSE_BUF_SIZE;
+
+    if (ret != 0) {
+        scsi_req_print(&r->req);
+        fprintf(stderr, "%s: ret %d (%s)\n", __FUNCTION__,
+                ret, strerror(-ret));
+        s->senselen = scsi_build_sense(SENSE_CODE(INVALID_FIELD),
+                    s->sensebuf, SCSI_SENSE_BUF_SIZE, 0);
+        s->driver_status = SG_ERR_DRIVER_SENSE;
+        r->req.status = CHECK_CONDITION;
+    } else {
+        if (s->driver_status & SG_ERR_DRIVER_TIMEOUT) {
+            scsi_req_print(&r->req);
+            fprintf(stderr, "%s: timeout\n", __FUNCTION__);
+            r->req.status = BUSY << 1;
+        } else if (r->bsg_hdr.device_status) {
+            r->req.status = r->bsg_hdr.device_status;
+        } else if (s->driver_status & SG_ERR_DRIVER_SENSE) {
+            scsi_req_print(&r->req);
+            fprintf(stderr, "%s: driver sense\n", __FUNCTION__);
+            r->req.status = CHECK_CONDITION << 1;
+        } else {
+            r->req.status = GOOD << 1;
+        }
+    }
+#ifdef DEBUG_BSG_IO
+    DPRINTF("Command complete 0x%p tag=0x%x status=%d\n",
+            r, r->req.tag, r->req.status);
+#endif
+    scsi_req_complete(&r->req);
+}
+
+static int bsg_execute_command_run(SCSIBSGReq *r,
+                                   BlockDriverCompletionFunc *complete)
+{
+    BlockDriverState *bdrv = r->req.dev->conf.dinfo->bdrv;
+    SCSIBSGState *s = DO_UPCAST(SCSIBSGState, qdev, r->req.dev);
+    /*
+     * Following linux/include/linux/bsg.h
+     */ 
+    /* [i] 'Q' to differentiate from v3 */
+    r->bsg_hdr.guard = 'Q';
+    r->bsg_hdr.protocol = BSG_PROTOCOL_SCSI;
+    r->bsg_hdr.subprotocol = BSG_SUB_PROTOCOL_SCSI_CMD;
+    r->bsg_hdr.request_len = r->req.cmd.len;
+    r->bsg_hdr.request = (unsigned long)r->req.cmd.buf;
+    r->bsg_hdr.max_response_len = sizeof(s->sensebuf);
+    /* SCSI: (auto)sense data */
+    r->bsg_hdr.response = (unsigned long)s->sensebuf;
+    /* Unlimited timeout */
+    r->bsg_hdr.timeout = MAX_UINT;
+    /* [i->o] unused internally */
+    r->bsg_hdr.usr_ptr = (unsigned long)r;
+    /* Bsg does Q_AT_HEAD by default */
+    r->bsg_hdr.flags |= BSG_FLAG_Q_AT_TAIL;
+
+    qemu_iovec_reset(&r->aio_iov);
+    qemu_iovec_add(&r->aio_iov, &r->bsg_hdr, sizeof(r->bsg_hdr));
+
+    r->req.aiocb = paio_submit_len(bdrv, bdrv->fd, 0, &r->aio_iov,
+                sizeof(r->bsg_hdr), complete, r, QEMU_AIO_WRITE);
+    if (r->req.aiocb == NULL) {
+        BADF("execute_command: paio_submit_len() failed\n");
+        return -1;
+    }
+
+    return 0;
+}
+
+static int bsg_execute_command_buf(SCSIBSGReq *r,
+                                   BlockDriverCompletionFunc *complete,
+                                   uint8_t *buf, uint32_t buflen)
+{
+    if (r->req.cmd.mode == SCSI_XFER_TO_DEV) {
+        r->bsg_hdr.dout_xferp = (unsigned long)buf;
+        r->bsg_hdr.dout_xfer_len = buflen;
+    } else if (r->req.cmd.mode == SCSI_XFER_FROM_DEV) {
+        r->bsg_hdr.din_xferp = (unsigned long)buf;
+        r->bsg_hdr.din_xfer_len = buflen;
+    }
+#ifdef DEBUG_BSG_IO
+    DPRINTF("execute BUF: %p, dxfer_len %u\n", buf, buflen);
+#endif
+    return bsg_execute_command_run(r, complete);
+}
+
+static int bsg_execute_command_iov(SCSIBSGReq *r,
+                                   BlockDriverCompletionFunc *complete,
+                                   QEMUIOVector *iov)
+{
+    if (r->req.cmd.mode == SCSI_XFER_TO_DEV) {
+        r->bsg_hdr.dout_iovec_count = iov->niov;
+        r->bsg_hdr.dout_xferp = (unsigned long)iov->iov;
+        r->bsg_hdr.dout_xfer_len = iov->size;
+    } else if (r->req.cmd.mode == SCSI_XFER_FROM_DEV) {
+        r->bsg_hdr.din_iovec_count = iov->niov;
+        r->bsg_hdr.din_xferp = (unsigned long)iov->iov;
+        r->bsg_hdr.din_xfer_len = iov->size;
+    }
+#ifdef DEBUG_BSG_IO
+    DPRINTF("execute IOV: iovec_count: %u, iov: %p, size: %u\n",
+            iov->niov, iov->iov, (unsigned int)iov->size);
+#endif
+    return bsg_execute_command_run(r, complete);
+}
+
+static void bsg_write_complete(void *opaque, int ret)
+{
+    SCSIBSGReq *r = (SCSIBSGReq *)opaque;
+    SCSIBSGState *s = DO_UPCAST(SCSIBSGState, qdev, r->req.dev);
+#ifdef DEBUG_BSG_IO
+    DPRINTF("bsg_write_complete() ret = %d\n", ret);
+#endif
+    if (ret) {
+        DPRINTF("IO error\n");
+        bsg_command_complete(r, ret);
+        return;
+    }
+    /*
+     * Copied from hw/scsi-generic.c:scsi_write_complete(), is this still
+     * necessary for BSG..?
+     */
+    if (r->req.cmd.buf[0] == MODE_SELECT && r->req.cmd.buf[4] == 12 &&
+        s->qdev.type == TYPE_TAPE) {
+        s->qdev.blocksize = (r->buf[9] << 16) | (r->buf[10] << 8) | r->buf[11];
+        DPRINTF("block size %d\n", s->qdev.blocksize);
+    }
+
+    bsg_command_complete(r, ret);
+}
+
+static void bsg_req_fixup(SCSIRequest *req)
+{
+    return;
+}
+
+static int bsg_get_blocksize(BlockDriverState *bdrv)
+{
+    uint8_t cmd[10];
+    uint8_t buf[8];
+    uint8_t sensebuf[8];
+    struct sg_io_v4 bsg_hdr;
+    int ret;
+
+    memset(cmd, 0, sizeof(cmd));
+    memset(buf, 0, sizeof(buf));
+    cmd[0] = READ_CAPACITY;
+
+    memset(&bsg_hdr, 0, sizeof(bsg_hdr));
+    bsg_hdr.guard = 'Q';
+    bsg_hdr.protocol = BSG_PROTOCOL_SCSI;
+    bsg_hdr.subprotocol = BSG_SUB_PROTOCOL_SCSI_CMD;
+    bsg_hdr.request_len = sizeof(cmd);
+    bsg_hdr.request = (unsigned long)cmd;
+    bsg_hdr.din_xfer_len = sizeof(buf);
+    bsg_hdr.din_xferp = (unsigned long)buf;
+    bsg_hdr.max_response_len = sizeof(sensebuf);
+    bsg_hdr.response = (unsigned long)sensebuf;
+    bsg_hdr.timeout = 6000; /* XXX */
+
+    ret = bdrv_ioctl(bdrv, SG_IO, (void *)&bsg_hdr);
+    if (ret < 0)
+        return -1;
+
+    return (buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7];
+}
+
+static int bsg_get_stream_blocksize(BlockDriverState *bdrv)
+{
+    uint8_t cmd[6];
+    uint8_t buf[12];
+    uint8_t sensebuf[8];
+    struct sg_io_v4 bsg_hdr;
+    int ret;
+
+    memset(cmd, 0, sizeof(cmd));
+    memset(buf, 0, sizeof(buf));
+    cmd[0] = MODE_SENSE;
+    cmd[4] = sizeof(buf);
+
+    memset(&bsg_hdr, 0, sizeof(bsg_hdr));
+    bsg_hdr.guard = 'Q';
+    bsg_hdr.protocol = BSG_PROTOCOL_SCSI;
+    bsg_hdr.subprotocol = BSG_SUB_PROTOCOL_SCSI_CMD;
+    bsg_hdr.request_len = sizeof(cmd);
+    bsg_hdr.request = (unsigned long)cmd;
+    bsg_hdr.din_xfer_len = sizeof(buf);
+    bsg_hdr.din_xferp = (unsigned long)buf;
+    bsg_hdr.max_response_len = sizeof(sensebuf);
+    bsg_hdr.response = (unsigned long)sensebuf;
+    bsg_hdr.timeout = 6000; /* XXX */
+
+    ret = bdrv_ioctl(bdrv, SG_IO, (void *)&bsg_hdr);
+    if (ret < 0)
+        return -1;
+
+    return (buf[9] << 16) | (buf[10] << 8) | buf[11];
+}
+
+static void bsg_destroy(SCSIDevice *d)
+{
+    SCSIBSGState *s = DO_UPCAST(SCSIBSGState, qdev, d);
+    SCSIBSGReq *r;
+
+    while (!QTAILQ_EMPTY(&s->qdev.requests)) {
+        r = DO_UPCAST(SCSIBSGReq, req, QTAILQ_FIRST(&s->qdev.requests));
+        bsg_remove_request(r);
+    }
+    drive_uninit(s->qdev.conf.dinfo);
+}
+
+struct scsi_idlun {
+    uint32_t dev_id;
+    uint32_t host_unique_id;
+};
+
+static int bsg_generic_initfn(SCSIDevice *dev)
+{
+    SCSIBSGState *s = DO_UPCAST(SCSIBSGState, qdev, dev);
+
+    if (!s->qdev.conf.dinfo || !s->qdev.conf.dinfo->bdrv) {
+        error_report("scsi-bsg: drive property not set");
+        return -1;
+    }
+    s->bs = s->qdev.conf.dinfo->bdrv;
+
+    /* check we are really using a /dev/bsg/ * file */
+    if (!bdrv_is_bsg(s->bs)) {
+        error_report("scsi-bsg: not BSG*");
+        return -1;
+    }
+#if 0
+    /* get LUN of the BSG */
+    if (bdrv_ioctl(s->bs, SG_GET_SCSI_ID, &scsiid)) {
+        error_report("scsi-bsg: SG_GET_SCSI_ID ioctl failed");
+        return -1;
+    }
+#endif
+// FIXME: Get SCSI lun from BSG 
+    s->lun = 0;
+// FIXME: Get SCSI device type from BSG INQUIRY
+    s->qdev.type = TYPE_DISK;
+    DPRINTF("LUN %d\n", s->lun);
+    DPRINTF("device type %d\n", s->qdev.type);
+
+    if (s->qdev.type == TYPE_TAPE) {
+        s->qdev.blocksize = bsg_get_stream_blocksize(s->bs);
+        if (s->qdev.blocksize == -1)
+            s->qdev.blocksize = 0;
+    } else {
+        s->qdev.blocksize = bsg_get_blocksize(s->bs);
+        /* removable media returns 0 if not present */
+        if (s->qdev.blocksize <= 0) {
+            if (s->qdev.type == TYPE_ROM || s->qdev.type  == TYPE_WORM)
+                s->qdev.blocksize = 2048;
+            else
+                s->qdev.blocksize = 512;
+        }
+    }
+    DPRINTF("block size %d\n", s->qdev.blocksize);
+    s->driver_status = 0;
+    memset(s->sensebuf, 0, sizeof(s->sensebuf));
+    return 0;
+}
+
+static void bsg_generic_unmap(SCSIBSGReq *r)
+{
+    int is_write = !scsi_req_is_write(&r->req);
+    int i;
+
+    for (i = 0; i < r->iov.niov; i++) {
+        cpu_physical_memory_unmap(r->iov.iov[i].iov_base,
+                                  r->iov.iov[i].iov_len, is_write,
+                                  r->iov.iov[i].iov_len);
+    }
+    qemu_iovec_reset(&r->iov);
+}
+
+static int bsg_generic_map(SCSIBSGReq *r, QEMUSGList *sg)
+{
+    int is_write = !scsi_req_is_write(&r->req);
+    target_phys_addr_t cur_addr, cur_len, cur_offset = 0;
+    void *mem;
+    int i;
+
+    qemu_iovec_reset(&r->iov);
+    for (i = 0; i < sg->nsg;) {
+        cur_addr = sg->sg[i].base + cur_offset;
+        cur_len = sg->sg[i].len - cur_offset;
+#ifdef DEBUG_BSG_MAP
+        DPRINTF("Using cur_addr: 0x%016lx cur_len: 0x%016lx\n",
+            (long unsigned int)cur_addr, (long unsigned int)cur_len);
+#endif
+        mem = cpu_physical_memory_map(cur_addr, &cur_len, is_write);
+        if (!mem)
+            goto err;
+#ifdef DEBUG_BSG_MAP
+        DPRINTF("Adding iovec for mem: %p len: 0x%016lx\n", mem,
+            (long unsigned int)cur_len);
+#endif
+        qemu_iovec_add(&r->iov, mem, cur_len);
+
+        cur_offset += cur_len;
+        if (cur_offset == sg->sg[i].len) {
+            cur_offset = 0;
+            i++;
+        }
+    }
+
+    return 0;
+
+err:
+    bsg_generic_unmap(r);
+    return -1;
+}
+
+static SCSIRequest *bsg_generic_req_get(SCSIDevice *d, uint32_t tag, int lun)
+{
+    SCSIBSGReq *r;
+
+    r = bsg_new_request(d, tag, lun);
+    return &r->req;
+}
+
+static void bsg_generic_req_cb(void *opaque, int ret)
+{
+    SCSIRequest *req = opaque;
+    SCSIBSGReq *r = DO_UPCAST(SCSIBSGReq, req, req);
+    SCSIBSGState *s = DO_UPCAST(SCSIBSGState, qdev, r->req.dev);
+    BlockDriverCompletionFunc *complete;
+    struct sg_io_v4 io_hdr;
+    int err;
+
+    req->aiocb = NULL;
+
+    memset(&io_hdr, 0, sizeof(io_hdr));
+    /* [i] 'Q' to differentiate from v3 */
+    io_hdr.guard = 'Q';
+
+    err = bsg_read(s->bs->fd, &io_hdr, sizeof(io_hdr));
+    if (err) {
+        printf("bsg_read() failed with ret: %d\n", err);
+        return;
+    }
+
+    if (r->iov.niov)
+        bsg_generic_unmap(r);
+
+    if (scsi_req_is_write(req)) {
+        req->xferlen = r->bsg_hdr.dout_xfer_len;
+        complete = bsg_write_complete;
+    } else {
+        req->xferlen = r->bsg_hdr.din_xfer_len;
+        complete = bsg_command_complete;
+    }
+    complete(opaque, ret);
+}
+
+static int bsg_generic_req_common(SCSIRequest *req, uint8_t *buffer)
+{
+    SCSIBSGReq *r = DO_UPCAST(SCSIBSGReq, req, req);
+    SCSIBSGState *s = DO_UPCAST(SCSIBSGState, qdev, r->req.dev);
+
+    bsg_req_fixup(&r->req);
+    if (req->cmd.buf[0] != REQUEST_SENSE &&
+        (req->lun != s->lun || (req->cmd.buf[1] >> 5) != s->lun)) {
+
+        DPRINTF("Unimplemented LUN %d\n",
+            req->lun ? req->lun : req->cmd.buf[1] >> 5);
+        s->senselen = scsi_build_sense(SENSE_CODE(LUN_NOT_SUPPORTED),
+                s->sensebuf, SCSI_SENSE_BUF_SIZE, 0);
+        s->driver_status = SG_ERR_DRIVER_SENSE;
+        req->status = CHECK_CONDITION << 1;
+        return 1;
+    }
+    if (r->req.cmd.buf[0] == REQUEST_SENSE &&
+        s->driver_status & SG_ERR_DRIVER_SENSE) {
+        req->xferlen = MIN(req->cmd.xfer, s->senselen);
+        memcpy(buffer, s->sensebuf, req->xferlen);
+        DPRINTF("Data ready tag=0x%x len=%d\n", r->req.tag, s->senselen);
+        DPRINTF("Sense: %d %d %d %d %d %d %d %d\n",
+                buffer[0], buffer[1], buffer[2], buffer[3],
+                buffer[4], buffer[5], buffer[6], buffer[7]);
+        req->status = GOOD;
+        return 1;
+    }
+    return 0;
+}
+
+static int bsg_generic_req_buf(SCSIRequest *req, uint8_t *buffer)
+{
+    SCSIBSGReq *r = DO_UPCAST(SCSIBSGReq, req, req);
+    int handled, ret;
+
+    handled = bsg_generic_req_common(req, buffer);
+    if (handled) {
+        scsi_req_complete(req);
+        return 0;
+    }
+
+    req->xferlen = req->cmd.xfer;
+    ret = bsg_execute_command_buf(r, bsg_generic_req_cb, buffer, req->xferlen);
+    if (ret == -1) {
+        bsg_command_complete(r, -EINVAL);
+    }
+    return 0;
+}
+
+static int bsg_generic_req_sgl(SCSIRequest *req, QEMUSGList *sg)
+{
+    SCSIBSGReq *r = DO_UPCAST(SCSIBSGReq, req, req);
+    int handled, ret;
+
+    if (bsg_generic_map(r, sg) != 0) {
+        /* Hmm ... */
+        abort();
+    }
+    handled = bsg_generic_req_common(req, r->iov.iov[0].iov_base);
+    if (handled) {
+        bsg_generic_unmap(r);
+        scsi_req_complete(req);
+        return 0;
+    }
+
+    req->xferlen = req->cmd.xfer;
+    ret = bsg_execute_command_iov(r, bsg_generic_req_cb, &r->iov);
+    if (ret == -1) {
+        bsg_generic_unmap(r);
+        bsg_command_complete(r, -EINVAL);
+    }
+    return 0;
+}
+
+static void bsg_generic_req_put(SCSIRequest *req)
+{
+    SCSIBSGReq *r = DO_UPCAST(SCSIBSGReq, req, req);
+
+    if (r->req.aiocb) {
+        bdrv_aio_cancel(r->req.aiocb);
+    }
+    bsg_remove_request(r);
+}
+
+static SCSIDeviceInfo bsg_info = {
+    .qdev.name      = "scsi-bsg",
+    .qdev.desc      = "pass through block layer scsi generic (/dev/bsg/*)",
+    .qdev.size      = sizeof(SCSIBSGState),
+    .init           = bsg_generic_initfn,
+    .destroy        = bsg_destroy,
+
+    /* new */
+    .request_get    = bsg_generic_req_get,
+    .request_buf    = bsg_generic_req_buf,
+    .request_sgl    = bsg_generic_req_sgl,
+    .request_put    = bsg_generic_req_put,
+
+    .qdev.props     = (Property[]) {
+        DEFINE_BLOCK_PROPERTIES(SCSIBSGState, qdev.conf),
+        DEFINE_PROP_END_OF_LIST(),
+    },
+};
+
+static void bsg_register_devices(void)
+{
+    scsi_qdev_register(&bsg_info);
+}
+device_init(bsg_register_devices)
+
+#endif /* __linux__ */
-- 
1.5.6.5