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Date: Mon, 04 May 2009 16:26:13 +0300
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] Re: [RFC] Bring in all the Linux headers we depend
	on	in QEMU
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To: Mark McLoughlin <markmc@redhat.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, kvm-devel <kvm@vger.kernel.org>

Mark McLoughlin wrote:
> On Mon, 2009-05-04 at 12:08 +0300, Avi Kivity wrote:
>   
>> In general a distro provides kernel headers matched to the running 
>> kernel.  For example F10 provides 
>> kernel-headers-2.6.27.21-170.2.56.fc10.x86_64 to go along with 
>> kernel-2.6.27.21-170.2.56.fc10.x86_64.  So a user running a distro 
>> kernel (the majority, given that most people don't inflict pain upon 
>> themselves unnecessarily) will have exactly the features exported by the 
>> kernel.
>>     
>
> Right, but if you e.g. try to build a newer qemu-kvm on F10, you
> currently need newer kvm kernel headers - IMHO, we should use #ifdef to
> allow newer qemu-kvm build with older kvm headers.
>
>   

qemu build against new headers should work fine on older hosts -- we 
discover features at runtime.  But I agree it's nice to be able to build 
against older headers.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.