Searched hist:fe921fc8b7e92020bb140079a9f47f14fb8e9075 (Results 1 – 3 of 3) sorted by relevance
| /openbmc/qemu/pc-bios/s390-ccw/ |
| H A D | scsi.h | diff fe921fc8b7e92020bb140079a9f47f14fb8e9075 Wed May 10 10:53:57 CDT 2017 Eric Farman <farman@linux.vnet.ibm.com> pc-bios/s390-ccw: Get Block Limits VPD device data
The "Block Limits" Inquiry VPD page is optional for any SCSI device,
but if it's supported it provides a hint of the maximum I/O transfer
length for this particular device. If this page is supported by the
disk, let's issue that Inquiry and use the minimum of it and the
SCSI controller limit. That will cover this scenario:
qemu-system-s390x ...
-device virtio-scsi-ccw,id=scsi0,max_sectors=32768 ...
-drive file=/dev/sda,if=none,id=drive0,format=raw ...
-device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,
drive=drive0,id=disk0,max_io_size=1048576
controller: 32768 sectors x 512 bytes/sector = 16777216 bytes
disk: 1048576 bytes
Now that we have a limit for a virtio-scsi disk, compare that with the
limit for the virtio-scsi controller when we actually build the I/O.
The minimum of these two limits should be the one we use.
Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Message-Id: <20170510155359.32727-7-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
|
| H A D | virtio-scsi.c | diff fe921fc8b7e92020bb140079a9f47f14fb8e9075 Wed May 10 10:53:57 CDT 2017 Eric Farman <farman@linux.vnet.ibm.com> pc-bios/s390-ccw: Get Block Limits VPD device data
The "Block Limits" Inquiry VPD page is optional for any SCSI device,
but if it's supported it provides a hint of the maximum I/O transfer
length for this particular device. If this page is supported by the
disk, let's issue that Inquiry and use the minimum of it and the
SCSI controller limit. That will cover this scenario:
qemu-system-s390x ...
-device virtio-scsi-ccw,id=scsi0,max_sectors=32768 ...
-drive file=/dev/sda,if=none,id=drive0,format=raw ...
-device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,
drive=drive0,id=disk0,max_io_size=1048576
controller: 32768 sectors x 512 bytes/sector = 16777216 bytes
disk: 1048576 bytes
Now that we have a limit for a virtio-scsi disk, compare that with the
limit for the virtio-scsi controller when we actually build the I/O.
The minimum of these two limits should be the one we use.
Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Message-Id: <20170510155359.32727-7-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
|
| H A D | virtio.h | diff fe921fc8b7e92020bb140079a9f47f14fb8e9075 Wed May 10 10:53:57 CDT 2017 Eric Farman <farman@linux.vnet.ibm.com> pc-bios/s390-ccw: Get Block Limits VPD device data
The "Block Limits" Inquiry VPD page is optional for any SCSI device,
but if it's supported it provides a hint of the maximum I/O transfer
length for this particular device. If this page is supported by the
disk, let's issue that Inquiry and use the minimum of it and the
SCSI controller limit. That will cover this scenario:
qemu-system-s390x ...
-device virtio-scsi-ccw,id=scsi0,max_sectors=32768 ...
-drive file=/dev/sda,if=none,id=drive0,format=raw ...
-device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,
drive=drive0,id=disk0,max_io_size=1048576
controller: 32768 sectors x 512 bytes/sector = 16777216 bytes
disk: 1048576 bytes
Now that we have a limit for a virtio-scsi disk, compare that with the
limit for the virtio-scsi controller when we actually build the I/O.
The minimum of these two limits should be the one we use.
Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Message-Id: <20170510155359.32727-7-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
|