Re: [Qemu-devel] [PATCH] xen: Restrict build to x86 targets

[Alexander Graf]

On 29.11.2010, at 15:27, Jan Kiszka wrote:

> Am 29.11.2010 15:15, Alexander Graf wrote:
>> 
>> On 29.11.2010, at 13:44, Jan Kiszka wrote:
>> 
>>> Am 29.11.2010 13:40, Alexander Graf wrote:
>>>> 
>>>> On 29.11.2010, at 13:30, Jan Kiszka wrote:
>>>> 
>>>>> Am 29.11.2010 13:24, Alexander Graf wrote:
>>>>>> 
>>>>>> On 28.11.2010, at 16:59, Jan Kiszka wrote:
>>>>>> 
>>>>>>> From: Jan Kiszka <address@hidden>
>>>>>>> 
>>>>>>> Xen target bits in qemu are intended for x86. Let the build system
>>>>>>> reflect this and avoid useless building/linking for other targets.
>>>>>> 
>>>>>> Not sure I understand the split. Xen is x86 only, yes. But why split it 
>>>>>> into host and target? Target usually defines the guest. The piece you 
>>>>>> marked as _HOST are target specific.
>>>>> 
>>>>> At least so far, the HOST part is build once for all targets into the
>>>>> host backend library. As this step injected CONFIG_XEN into all target
>>>>> builds, even non-x86 targets built xen_machine_pv and xen_domainbuild.
>>>>> That's addressed by the patch.
>>>> 
>>>> I still don't understand the need for that split.
>>> 
>>> Enable Xen and build some non-x86 targets, then you see the need.
>>> 
>>>> The device drivers should be built only once, as do the xen_machine_pv 
>>>> parts. Both are useless on non-x86. CONFIG_XEN should simply always be a 
>>>> target specific option.
>>> 
>>> Maybe the split-up between the "generic" host-side interfaces and
>>> xen_machine_pv/xen_domainbuild is the problem. You know the dependencies
>>> better than me, maybe you find a better fix.
>> 
>> Should be enough to just replace obj-$(CONFIG_XEN) by obj-i386-$(CONFIG_XEN).
> 
> Indeed (as long as qemu's xen remains x86-only).

I'm 99.9% sure it will :).

>> Unless it's very urgent, please wait with this patch until qemu-dm and 
>> xenner are in. It's pretty suboptimal to have 3 patches flying around that 
>> hit the exact same code spot :).
> 
> It isn't urgent. If patches series refactor the stuff and fix the
> dependency, I'm happy to wait for them.

They don't really refactor it, but add a lot more dependencies. Anthony, since 
you probably need yet another round for the 4.0 compile stuff, feel like 
putting this on your TODO list too? (Sorry this takes so long :( - I'll try to 
review stuff quicker next time around)


Alex