Now that we've read all the possible limits that have been defined for
a virtio-scsi controller and the disk we're booting from, it's possible
that we are STILL going to exceed the limits of the host device.
For example, a "-device scsi-generic" device does not support the
Block Limits VPD page.
So, let's fallback to something that seems to work for most boot
configurations if larger values were specified (including if nothing
was explicitly specified, and we took default values).
Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Message-Id: <20170510155359.32727-8-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
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>
The "Supported Pages" Inquiry EVPD page is mandatory for all SCSI devices,
and is used as a gateway for what VPD pages the device actually supports.
Let's issue this Inquiry, and dump that list with the debug facility.
Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Message-Id: <20170510155359.32727-6-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
If we want to issue any of the SCSI Inquiry EVPD pages,
which we do, we could use this function to issue both types
of commands with a little bit of refactoring.
Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Message-Id: <20170510155359.32727-5-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
A virtio-scsi request that goes through the host sd driver and exceeds
the maximum transfer size is automatically broken up for us. But the
equivalent request going to the sg driver presumes that any length
requirements have already been honored.
Let's use the max_sectors field on the virtio-scsi controller device,
and break up all requests (both sd and sg) to avoid this problem.
Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Message-Id: <20170510155359.32727-4-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Simple refactoring so that the blk_factor adjustment is
moved into virtio_scsi_read_many routine, in preparation
for another change.
Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Message-Id: <20170510155359.32727-3-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
When using virtio-scsi, we multiply the READ(10) data_size by
a block factor twice when building the I/O. This is fine,
since it's only 1 for SCSI disks, but let's clean it up.
Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <20170510155359.32727-2-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
There is ,bootindex=%d argument to specify the lookup order of
boot devices.
If a bootindex assigned to the device, then IPL Parameter Info Block
is created for that device when it is IPLed from.
If it is a mere SCSI device (not FCP), then IPIB is created with a
special SCSI type and its fields are used to store SCSI address of the
device. This new ipl block is private to qemu for now.
If the device to IPL from is specified this way, then SCSI bus lookup
is bypassed and prescribed devices uses the address specified.
Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
