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scsi-disk.c: consider bl->max_transfer in INQUIRY emulation 

The calculation of the max_transfer atribute of BlockDriverState
makes considerations such as max_segments and transfer_length via
the BLKSECTGET ioctl (if available).

However, bl->max_transfer isn't considered when emulating the INQUIRY
'Block Limit' response to the scsi-hd devices. This leads to situations
where the declared max_sectors from the INQUIRY response is inconsistent
with the block limits, which isn't ideal. It can also be misleading to the
user that sets /sys/block/<dev>/queue/max_sectors_kb to a certain
value, then finds a different value in the guest OS for the same disk.

Following the same logic scsi_read_complete from scsi-generic.c does
when patching the response of the Block Limits VPD back to the guest,
change the max_io_sectors value of the emulated Block Limits VPD
response by considering the blk_get_max_transfer of the related
BlockDriverState. Use MIN_NOT_ZERO to be sure that the minimal
value is chosen.

Given that we're changing max_io_sectors, consider that min_io_sectors
and opt_io_sectors can't be greater than the new calculated value.

Signed-off-by: Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-Id: <20180306154411.18462-1-danielhb@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Daniel Henrique Barboza 2018-03-06 12:44:11 -03:00 committed by Paolo Bonzini
parent 4b9c264bd2
commit d082d16a5c
1 changed files with 15 additions and 0 deletions
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15
hw/scsi/scsi-disk.c
View File

@ -704,6 +704,21 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req, uint8_t *outbuf)
page_code);
return -1;
}
if (s->qdev.type == TYPE_DISK) {
int max_transfer_blk = blk_get_max_transfer(s->qdev.conf.blk);
int max_io_sectors_blk =
max_transfer_blk / s->qdev.blocksize;
max_io_sectors =
MIN_NON_ZERO(max_io_sectors_blk, max_io_sectors);
/* min_io_size and opt_io_size can't be greater than
* max_io_sectors */
min_io_size =
MIN_NON_ZERO(min_io_size, max_io_sectors);
opt_io_size =
MIN_NON_ZERO(opt_io_size, max_io_sectors);
}
/* required VPD size with unmap support */
buflen = 0x40;
memset(outbuf + 4, 0, buflen - 4);