|
From: | Christian Ehrhardt |
Subject: | [Qemu-devel] Re: [PATCH] qemu: fix configuring kvm probe when using --kerneldir |
Date: | Mon, 12 Jan 2009 07:42:34 +0100 |
User-agent: | Thunderbird 2.0.0.19 (X11/20090105) |
Andre Przywara wrote:
address@hidden wrote:I also stumbled over this recently (in kvm-userspace.git), but I had problems with the qemu part not including KVM support because in qemu/configure the KVM build test failed due to the missing asm/kvm.h. I saw that --kerneldir gets not propagated to qemu, but libkvm_kerneldir instead, which is hardcoded to point to `pwd`/kernel. Shouldn't that be fixed, too? I use kvm-userspace.git and a not-installed kernel from kvm.git for compiling, so I say "./configure --kerneldir=/src/kvm.git --with-patched-kernel". I eventually hacked KVM's configure to propagate --kerneldir to qemu and added arch/x86/include to the include path in qemu/configure. This is of course a hack (that's why I don't append it here), but it worked ;-) If someone proposes a clean and easy way to solve this, I'd be happy to write a patch.From: Christian Ehrhardt <address@hidden> There is already a variable kvm_cflags which gets the path of the kernelincludes when using --kerneldir. But eventually with newer kernels we all will need arch/$arch/include too (my case was a incldue of asm/kvm.h which was notfound anymore). Headers in a full kernel source are not flattened to one arch like they are if e.g. installed kernel headers are used.
I know this issue and reported it ~a month ago. I also had issues compiling against a --kerneldir kernel because the libkvm_kerneldir was propagated. Eventually in the discussion it came up that we don't need to fix configure "technically", but maybe we should find a way to better inform users/developüers about this (I guess up to 99% that this works for you in kvm-userspace too):
(in a clean kvm-userspace) cd kernel make sync LINUX=path/to/your/kerneldir cd .. ./configure opt=whateveryouwantThis way your kerneldir is synced and flattened into kvm-userspace and propagating libkvm_kerneldir is fine since that are your kerneldir headers now. Maybe a "fix" would be that if --kerneldir is provided to configure it has to ensure that THIS kerneldir is synced in before continuing. You should be aware that the fix I sent on Friday was for plain qemu which doesn't have that kernel subdir indirection and therefore works a bit different.
To fix that, the includes added to cflags depending on --kerneldir should also contian the arch includes. The patch adds a special check for x86 because its source layout recently changed, all others directly use arch/$cpu/include ifThis is one problem I also noticed. $cpu is not the same as the Linux' arch name, is there a suitable variable or do we have to do a large switch/case?existent.
I looked around and there was no real 1:1 matching variable. But fortunately $cpu is similar enough to simplify that swicth/case a lot like I did in my patch here.
Regards, Andre.Signed-off-by: Christian Ehrhardt <address@hidden> --- [diffstat] configure | 6 ++++++ 1 file changed, 6 insertions(+) [diff] diff --git a/configure b/configure --- a/configure +++ b/configure @@ -963,6 +963,12 @@ EOF EOF if test "$kerneldir" != "" ; then kvm_cflags=-I"$kerneldir"/include + if test \( "$cpu" = "i386" -o "$cpu" = "x86_64" \) \ + -a -d "$kerneldir/arch/x86/include" ; then + kvm_cflags="$kvm_cflags -I$kerneldir/arch/x86/include" + elif test -d "$kerneldir/arch/$cpu/include" ; then + kvm_cflags="$kvm_cflags -I$kerneldir/arch/$cpu/include" + fi else kvm_cflags="" fi
--Grüsse / regards, Christian Ehrhardt
IBM Linux Technology Center, Open Virtualization
[Prev in Thread] | Current Thread | [Next in Thread] |