| Message ID | 20180306154411.18462-1-danielhb@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/1] scsi-disk.c: consider bl->max_transfer in INQUIRY emulation | expand |
On Tue, 03/06 12:44, Daniel Henrique Barboza wrote: > 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> > --- > hw/scsi/scsi-disk.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c > index 49d2559d93..c65c1ce56d 100644 > --- a/hw/scsi/scsi-disk.c > +++ b/hw/scsi/scsi-disk.c > @@ -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); > -- > 2.14.3 > Reviewed-by: Fam Zheng <famz@redhat.com>
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c index 49d2559d93..c65c1ce56d 100644 --- a/hw/scsi/scsi-disk.c +++ b/hw/scsi/scsi-disk.c @@ -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);
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> --- hw/scsi/scsi-disk.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)