Re: [kvm-ia64-devel] Cross-arch support for make sync in userspace

[Avi K. <av...@qu...>]

Zhang, Xiantao wrote:
> Avi Kivity wrote:
>   
>> Zhang, Xiantao wrote:
>>     
>>> Hi, Avi
>>> Currently, make sync in userspace only syncs x86-specific heads from
>>> kernel source due to hard-coded in Makefile.
>>> Do you have plan to provide cross-arch support for that?
>>>       
>> No plans.  I'll apply patches though.  But don't you need kernel
>> changes which make it impossible to run kvm-ia64 on older kernels?
>>
>>     
>>> Other archs may
>>> need it for save/restore :)
>>>
>>>       
>> Save/restore?  Don't understand.
>>     
>
> You know, currently make sync would sync header files to userspace from
> include/asm-x86/, so kvm.h and kvm_host.h are always synced from there
> for any archs. Since some arch-specific stuff for save/restore should be
> defined in include/asm-$arch/(kvm.h; kvm_host.h), so ia64 or other archs
> should need it when they implement save/restore.  

I see.  But is 'make sync' actually useful for you?  Can you run 
kvm-ia64 on top of 2.6.24, which doesn't include your ia64 core API changes?

Note you will also need to add preempt notifier emulation for older kernels.

-- 
Any sufficiently difficult bug is indistinguishable from a feature.