Re: [Qemu-devel] [PATCH] Import KVM headers including Makefile andimportscript

[Avi Kivity <avi@redhat.com>]

Anthony Liguori wrote:
> Avi Kivity wrote:
>> Anthony Liguori wrote:
>>>> Can we put them under kvm/, as include/ looks like a generic 
>>>> include directory, which this isn't.  Also, this generates a 
>>>> gratuitous conflict with qemu-kvm.git, and we have enough of those 
>>>> already.
>>>
>>> I'd rather put them under linux/ because right now, we depend on a 
>>> number of Linux headers (for USB pass through, for instance).
>>>
>>> The qemu-kvm.git layout is kvm/kernel/include.  That doesn't seem to 
>>> make a lot of sense for QEMU.
>>
>> linux/ makes sense.  But let's coordinate the change.
>
> BTW, the next logic step for qemu-kvm.git is to move /libkvm/libkvm.c 
> to /libkvm-all.c, then move /libkvm/libkvm-<arch>.c to 
> /target-<arch>/libkvm.c.  Then make each target that supports kvm 
> depend on libkvm-all.o and libkvm.o.  kvmctl can be moved to the 
> top-level too and treated like another qemu tool.  The trick is to 
> build a kvmctl-libkvm.o or something like that but it should be too 
> difficult.

My plan for kvmctl is to port the tests to 'qemu -kernel' and retire 
it.  We can use standard serial or virtio-console for logging.  We'll 
need some fake devices for the testing, but they'd all be very simple.

Given that, we can start porting things from libkvm to kvm-all.c and 
eventually remove it.

>> Let's avoid it altogether (we can avoid the compiler.h hack by adding 
>> a dummy <linux/compiler.h>).
>
> I still think a fixup is needed because once concern I have is that 
> it's far too brittle in its current state.  It's too easy to not pull 
> in a header and end up using /usr/include/linux/foo.h.  This could 
> lead to very subtle build errors that would be host OS dependent.

Not to mention, libc would see a mix of the newer kernel headers and the 
system kernel headers.

> So I'm thinking that a common prefix to avoid confusion is warranted.  
> So the fixup would become:
>
> s:^#include <linux/\(.*\)>:#include "host/linux/\1":g
> s:^#include <asm/\(.*\)>:#include "host/asm/\1":g
>
> And we'd change all the existing #includes to use "host/foo".  I think 
> that would make it much more robust.
>

But pretty ugly :(; maybe we can find a cleaner solution.

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