[Qemu-devel] MegaSAS 8708EM2 qemu-kvm.git tree updated to v0.12.5

[Nicholas A. Bellinger]

Greetings Hannes, hch and Co,

The lastest code from upstream qemu-kvm.git v0.12.5 has been merged into
the megasas HBA emulation friendly qemu-kvm.git/master and scsi-bsg
branches at:

http://git.kernel.org/?p=virt/kvm/nab/qemu-kvm.git;a=summary

The merge commitdiffs for master and scsi-bsg can be found here:

http://git.kernel.org/?p=virt/kvm/nab/qemu-kvm.git;a=commitdiff;h=331578e7e362b33c965d469ea4577956dd431bbc
http://git.kernel.org/?p=virt/kvm/nab/qemu-kvm.git;a=commitdiff;h=2eebcfd04adda1fee641a776c9a85dda95c43b43

The megasas HBA emulation has been given a quick test with scsi-generic
and scsi-bsg backstores into TCM_Loop FILEIO LUNs with x86_64 v2.6.26
guests on a x86_64 v2.6.35 host.  So far things appear to be functioning
as expected with the megasas SGL passthrough logic and v0.12.5 upstream
qemu-kvm code.

There was also some new upstream code in hw/scsi-disk.c which does not
seem to be required with the SGL passthrough logic, and that I ended up
dropping for the v0.12.5 merge.  The code that that was dropped during
the merge starts with scsi_command_complete() at:

http://git.kernel.org/?p=virt/kvm/qemu-kvm.git;a=blob;f=hw/scsi-disk.c;hb=HEAD#l101

and includes everything down to scsi_write_data().  Using scsi-disk was
also given a quick test and appears to be functioning as expected using
passthrough SGL logic and userspace QEMU SCSI CDB emulation.

Note there does appear to be some breakage with the SGL passthrough and
recent upstream changes with hw/lsi53c895a.c to use a local dma_buf
pointer and to get rid of LSIState->select_dev.  While I had verified
that the SGL passthrough code was working with lsi53c895a on v0.12.4
with scsi-generic+scsi-bsg backstores, this is now segfaulting for me
after the latest upstream merge.  I will need to have another look at
this, but if someone who has more knowledge with hw/lsi53c895a.c could
help out, it would be much apperciated.  ;)

Comments are welcome!

Best,

--nab