scsi-generic.c

xen虚拟机源代码安装包

/*
 * Generic SCSI Device support
 *
 * Copyright (c) 2007 Bull S.A.S.
 * Based on code by Paul Brook
 * Based on code by Fabrice Bellard
 *
 * Written by Laurent Vivier <[e-mail]>
 *
 * This code is licenced under the LGPL.
 *
 */

#include "qemu-common.h"
#include "block.h"
#include "scsi-disk.h"

#ifndef __linux__

SCSIDevice *scsi_generic_init(BlockDriverState *bdrv, int tcq,
                              scsi_completionfn completion, void *opaque)
{
    return NULL;
}

#else /* __linux__ */

//#define DEBUG_SCSI

#ifdef DEBUG_SCSI
#define DPRINTF(fmt, args...) \
do { printf("scsi-generic: " fmt , ##args); } while (0)
#else
#define DPRINTF(fmt, args...) do {} while(0)
#endif

#define BADF(fmt, args...) \
do { fprintf(stderr, "scsi-generic: " fmt , ##args); } while (0)

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <scsi/sg.h>
#include <scsi/scsi.h>

#define LOAD_UNLOAD 0xa6
#define SET_CD_SPEED 0xbb
#define BLANK 0xa1

#define SCSI_CMD_BUF_SIZE     16
#define SCSI_SENSE_BUF_SIZE 32

#define SG_ERR_DRIVER_TIMEOUT 0x06
#define SG_ERR_DRIVER_SENSE 0x08

#ifndef MAX_UINT
#define MAX_UINT ((unsigned int)-1)
#endif

typedef struct SCSIRequest {
    BlockDriverAIOCB *aiocb;
    struct SCSIRequest *next;
    SCSIDeviceState *dev;
    uint32_t tag;
    uint8_t cmd[SCSI_CMD_BUF_SIZE];
    int cmdlen;
    uint8_t *buf;
    int buflen;
    int len;
    sg_io_hdr_t io_header;
} SCSIRequest;

struct SCSIDeviceState
{
    SCSIRequest *requests;
    BlockDriverState *bdrv;
    int blocksize;
    int lun;
    scsi_completionfn completion;
    void *opaque;
    int driver_status;
    uint8_t sensebuf[SCSI_SENSE_BUF_SIZE];
};

/* Global pool of SCSIRequest structures.  */
static SCSIRequest *free_requests = NULL;

static SCSIRequest *scsi_new_request(SCSIDeviceState *s, uint32_t tag)
{
    SCSIRequest *r;

    if (free_requests) {
        r = free_requests;
        free_requests = r->next;
    } else {
        r = qemu_malloc(sizeof(SCSIRequest));
        r->buf = NULL;
        r->buflen = 0;
    }
    r->dev = s;
    r->tag = tag;
    memset(r->cmd, 0, sizeof(r->cmd));
    memset(&r->io_header, 0, sizeof(r->io_header));
    r->cmdlen = 0;
    r->len = 0;
    r->aiocb = NULL;

    /* link */

    r->next = s->requests;
    s->requests = r;
    return r;
}

static void scsi_remove_request(SCSIRequest *r)
{
    SCSIRequest *last;
    SCSIDeviceState *s = r->dev;

    if (s->requests == r) {
        s->requests = r->next;
    } else {
        last = s->requests;
        while (last && last->next != r)
            last = last->next;
        if (last) {
            last->next = r->next;
        } else {
            BADF("Orphaned request\n");
        }
    }
    r->next = free_requests;
    free_requests = r;
}

static SCSIRequest *scsi_find_request(SCSIDeviceState *s, uint32_t tag)
{
    SCSIRequest *r;

    r = s->requests;
    while (r && r->tag != tag)
        r = r->next;

    return r;
}

/* Helper function for command completion.  */
static void scsi_command_complete(void *opaque, int ret)
{
    SCSIRequest *r = (SCSIRequest *)opaque;
    SCSIDeviceState *s = r->dev;
    uint32_t tag;
    int sense;

    s->driver_status = r->io_header.driver_status;
    if (ret != 0)
        sense = HARDWARE_ERROR;
    else {
        if (s->driver_status & SG_ERR_DRIVER_TIMEOUT) {
            sense = HARDWARE_ERROR;
            BADF("Driver Timeout\n");
        } else if ((s->driver_status & SG_ERR_DRIVER_SENSE) == 0)
            sense = NO_SENSE;
        else
            sense = s->sensebuf[2] & 0x0f;
    }

    DPRINTF("Command complete 0x%p tag=0x%x sense=%d\n", r, r->tag, sense);
    tag = r->tag;
    scsi_remove_request(r);
    s->completion(s->opaque, SCSI_REASON_DONE, tag, sense);
}

/* Cancel a pending data transfer.  */
static void scsi_cancel_io(SCSIDevice *d, uint32_t tag)
{
    DPRINTF("scsi_cancel_io 0x%x\n", tag);
    SCSIDeviceState *s = d->state;
    SCSIRequest *r;
    DPRINTF("Cancel tag=0x%x\n", tag);
    r = scsi_find_request(s, tag);
    if (r) {
        if (r->aiocb)
            bdrv_aio_cancel(r->aiocb);
        r->aiocb = NULL;
        scsi_remove_request(r);
    }
}

static int execute_command(BlockDriverState *bdrv,
                           SCSIRequest *r, int direction,
			   BlockDriverCompletionFunc *complete)
{

    r->io_header.interface_id = 'S';
    r->io_header.dxfer_direction = direction;
    r->io_header.dxferp = r->buf;
    r->io_header.dxfer_len = r->buflen;
    r->io_header.cmdp = r->cmd;
    r->io_header.cmd_len = r->cmdlen;
    r->io_header.mx_sb_len = sizeof(r->dev->sensebuf);
    r->io_header.sbp = r->dev->sensebuf;
    r->io_header.timeout = MAX_UINT;
    r->io_header.usr_ptr = r;
    r->io_header.flags |= SG_FLAG_DIRECT_IO;

    if (bdrv_pwrite(bdrv, -1, &r->io_header, sizeof(r->io_header)) == -1) {
        BADF("execute_command: write failed ! (%d)\n", errno);
        return -1;
    }
    if (complete == NULL) {
        int ret;
        r->aiocb = NULL;
        while ((ret = bdrv_pread(bdrv, -1, &r->io_header,
                                           sizeof(r->io_header))) == -1 &&
                      errno == EINTR);
        if (ret == -1) {
            BADF("execute_command: read failed !\n");
            return -1;
        }
        return 0;
    }

    r->aiocb = bdrv_aio_read(bdrv, 0, (uint8_t*)&r->io_header,
                          -(int64_t)sizeof(r->io_header), complete, r);
    if (r->aiocb == NULL) {
        BADF("execute_command: read failed !\n");
        return -1;
    }

    return 0;
}

static void scsi_read_complete(void * opaque, int ret)
{
    SCSIRequest *r = (SCSIRequest *)opaque;
    SCSIDeviceState *s = r->dev;
    int len;

    if (ret) {
        DPRINTF("IO error\n");
        scsi_command_complete(r, ret);
        return;
    }
    len = r->io_header.dxfer_len - r->io_header.resid;
    DPRINTF("Data ready tag=0x%x len=%d\n", r->tag, len);

    r->len = -1;
    s->completion(s->opaque, SCSI_REASON_DATA, r->tag, len);
}

/* Read more data from scsi device into buffer.  */
static void scsi_read_data(SCSIDevice *d, uint32_t tag)
{
    SCSIDeviceState *s = d->state;
    SCSIRequest *r;
    int ret;

    DPRINTF("scsi_read_data 0x%x\n", tag);
    r = scsi_find_request(s, tag);
    if (!r) {
        BADF("Bad read tag 0x%x\n", tag);
        /* ??? This is the wrong error.  */
        scsi_command_complete(r, -EINVAL);
        return;
    }

    if (r->len == -1) {
        scsi_command_complete(r, 0);
        return;
    }

    if (r->cmd[0] == REQUEST_SENSE && s->driver_status & SG_ERR_DRIVER_SENSE)
    {
        memcpy(r->buf, s->sensebuf, 16);
        r->io_header.driver_status = 0;
        r->len = -1;
        s->completion(s->opaque, SCSI_REASON_DATA, r->tag, 16);
        return;
    }

    ret = execute_command(s->bdrv, r, SG_DXFER_FROM_DEV, scsi_read_complete);
    if (ret == -1) {
        scsi_command_complete(r, -EINVAL);
        return;
    }
}

static void scsi_write_complete(void * opaque, int ret)
{
    SCSIRequest *r = (SCSIRequest *)opaque;

    DPRINTF("scsi_write_complete() ret = %d\n", ret);
    if (ret) {
        DPRINTF("IO error\n");
        scsi_command_complete(r, ret);
        return;
    }

    scsi_command_complete(r, ret);
}

/* Write data to a scsi device.  Returns nonzero on failure.
   The transfer may complete asynchronously.  */
static int scsi_write_data(SCSIDevice *d, uint32_t tag)
{
    SCSIDeviceState *s = d->state;
    SCSIRequest *r;
    int ret;

    DPRINTF("scsi_write_data 0x%x\n", tag);
    r = scsi_find_request(s, tag);
    if (!r) {
        BADF("Bad write tag 0x%x\n", tag);
        /* ??? This is the wrong error.  */
        scsi_command_complete(r, -EINVAL);
        return 0;
    }

    if (r->len == 0) {
        r->len = r->buflen;
        s->completion(s->opaque, SCSI_REASON_DATA, r->tag, r->len);
        return 0;
    }

    ret = execute_command(s->bdrv, r, SG_DXFER_TO_DEV, scsi_write_complete);