Re: [PATCH 3/3] kvm-s390: streamline memslot handling

[Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>]

Avi Kivity wrote:
> Christian Bornträger wrote:
>> Am Dienstag 26 Mai 2009 09:57:58 schrieb Avi Kivity:
>>   
[...]
>> In our low-level interrupt handler we do check for signal_pending, 
>> machine_check_pending and need_resched to leave the sie instruction. 
>> For anything else a the host sees a cpu bound guest always in the SIE 
>> instruction.   
>
> Okay, now I understand (and agree with) you multi-level kick thing.  
> Maybe we could do it like so:
>
> Interrupt handler (on s390 only) checks vcpu->requests, handles the 
> ones it cans.  If bits are still set, it exits to arch loop, which 
> handles the bits it cans.  If bits are still set, it exits to the 
> generic code loop, which can finally exit to userspace.
>
> Does this fit with s390 hardware?
>
I like this idea instead of explicitly kicking to an (upper) level to 
use the lowest kick and exit if not able to handle.
I think it should work (no guarantee) and I try to come up with 
something in the next few days - either a updated patch series or 
additional discussion input :-).

-- 

Grüsse / regards, Christian Ehrhardt
IBM Linux Technology Center, Open Virtualization