Re: [Qemu-devel] [PATCH 8/8] s390: Add new channel I/O based virtio transport.

[Alexander Graf]

On 16.01.2013, at 17:46, Richard Henderson wrote:

> $SUBJECT reminds me that the tcg s390x port is now prepared
> to implement channel insns, but previously there were no
> channels worth talking about:
> 
>> /* I/O Instructions.  For each we simply indicate non-operation.  */
>>    C(0xb276, XSCH,    S,     Z,   0, 0, 0, 0, subchannel, 0)
>>    C(0xb230, CSCH,    S,     Z,   0, 0, 0, 0, subchannel, 0)
>>    C(0xb231, HSCH,    S,     Z,   0, 0, 0, 0, subchannel, 0)
>>    C(0xb232, MSCH,    S,     Z,   0, 0, 0, 0, subchannel, 0)
>>    C(0xb23b, RCHP,    S,     Z,   0, 0, 0, 0, subchannel, 0)
>>    C(0xb238, RSCH,    S,     Z,   0, 0, 0, 0, subchannel, 0)
>>    C(0xb233, SSCH,    S,     Z,   0, 0, 0, 0, subchannel, 0)
>>    C(0xb234, STSCH,   S,     Z,   0, 0, 0, 0, subchannel, 0)
>>    C(0xb235, TSCH,    S,     Z,   0, 0, 0, 0, subchannel, 0)
> 
> With a bit of help, I can make these emulated insns implement
> virtio as well.

Cool! I would assume that

  http://marc.info/?l=linux-s390&m=135488344028834&w=2

and most of this thread

  http://lists.gnu.org/archive/html/qemu-devel/2012-12/msg00837.html

would be enough help to actually implement them. Though I'd personally prefer 
if we can get the IBM folks to do a proper implementation that works for KVM 
first. Once that is there, doing the rest of the plumbing shouldn't be too hard.


Alex