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[Qemu-devel] Re: [PATCH] qemu: fix configuring kvm probe when using --ke
[Qemu-devel] Re: [PATCH] qemu: fix configuring kvm probe when using --kerneldir
Mon, 12 Jan 2009 07:42:34 +0100
Thunderbird 188.8.131.52 (X11/20090105)
Andre Przywara 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 kernel
includes when using --kerneldir. But eventually with newer kernels we
need arch/$arch/include too (my case was a incldue of asm/kvm.h which
found 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)
make sync LINUX=path/to/your/kerneldir
This way your kerneldir is synced and flattened into kvm-userspace and
propagating libkvm_kerneldir is fine since that are your kerneldir
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
To fix that, the includes added to cflags depending on --kerneldir
contian the arch includes. The patch adds a special check for x86
source layout recently changed, all others directly use
This 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
I looked around and there was no real 1:1 matching variable. But
fortunately $cpu is similar enough to simplify that swicth/case a lot
like I did in my patch here.
Signed-off-by: Christian Ehrhardt <address@hidden>
configure | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/configure b/configure
@@ -963,6 +963,12 @@ EOF
if test "$kerneldir" != "" ; then
+ 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"
Grüsse / regards,
IBM Linux Technology Center, Open Virtualization