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scsi-generic: snoop READ CAPACITY commands to get block size 

Instead of "guessing" the block size when there is no medium in the
drive, wait for the guest to send a READ CAPACITY command and snoop
it from there.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Paolo Bonzini 2011-10-13 10:36:27 +02:00 committed by Kevin Wolf
parent a3b16e71ab
commit 9b6eef8a31
1 changed files with 25 additions and 41 deletions
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66
hw/scsi-generic.c
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@ -155,6 +155,7 @@ static int execute_command(BlockDriverState *bdrv,
static void scsi_read_complete(void * opaque, int ret)
{
SCSIGenericReq *r = (SCSIGenericReq *)opaque;
SCSIDevice *s = r->req.dev;
int len;
r->req.aiocb = NULL;
@ -170,6 +171,15 @@ static void scsi_read_complete(void * opaque, int ret)
if (len == 0) {
scsi_command_complete(r, 0);
} else {
/* Snoop READ CAPACITY output to set the blocksize. */
if (r->req.cmd.buf[0] == READ_CAPACITY_10) {
s->blocksize = ldl_be_p(&r->buf[4]);
} else if (r->req.cmd.buf[0] == SERVICE_ACTION_IN_16 &&
(r->req.cmd.buf[1] & 31) == SAI_READ_CAPACITY_16) {
s->blocksize = ldl_be_p(&r->buf[8]);
}
bdrv_set_buffer_alignment(s->conf.bs, s->blocksize);
scsi_req_data(&r->req, len);
}
}
@ -298,36 +308,6 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t *cmd)
}
}
static int get_blocksize(BlockDriverState *bdrv)
{
uint8_t cmd[10];
uint8_t buf[8];
uint8_t sensebuf[8];
sg_io_hdr_t io_header;
int ret;
memset(cmd, 0, sizeof(cmd));
memset(buf, 0, sizeof(buf));
cmd[0] = READ_CAPACITY_10;
memset(&io_header, 0, sizeof(io_header));
io_header.interface_id = 'S';
io_header.dxfer_direction = SG_DXFER_FROM_DEV;
io_header.dxfer_len = sizeof(buf);
io_header.dxferp = buf;
io_header.cmdp = cmd;
io_header.cmd_len = sizeof(cmd);
io_header.mx_sb_len = sizeof(sensebuf);
io_header.sbp = sensebuf;
io_header.timeout = 6000; /* XXX */
ret = bdrv_ioctl(bdrv, SG_IO, &io_header);
if (ret < 0 || io_header.driver_status || io_header.host_status) {
return -1;
}
return (buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7];
}
static int get_stream_blocksize(BlockDriverState *bdrv)
{
uint8_t cmd[6];
@ -413,21 +393,25 @@ static int scsi_generic_initfn(SCSIDevice *s)
/* define device state */
s->type = scsiid.scsi_type;
DPRINTF("device type %d\n", s->type);
if (s->type == TYPE_TAPE) {
switch (s->type) {
case TYPE_TAPE:
s->blocksize = get_stream_blocksize(s->conf.bs);
if (s->blocksize == -1) {
s->blocksize = 0;
}
} else {
s->blocksize = get_blocksize(s->conf.bs);
/* removable media returns 0 if not present */
if (s->blocksize <= 0) {
if (s->type == TYPE_ROM || s->type == TYPE_WORM) {
s->blocksize = 2048;
} else {
s->blocksize = 512;
}
}
break;
/* Make a guess for block devices, we'll fix it when the guest sends.
* READ CAPACITY. If they don't, they likely would assume these sizes
* anyway. (TODO: they could also send MODE SENSE).
*/
case TYPE_ROM:
case TYPE_WORM:
s->blocksize = 2048;
break;
default:
s->blocksize = 512;
break;
}
DPRINTF("block size %d\n", s->blocksize);