On Mon, Apr 12, 2010 at 4:50 PM, Pasi Kärkkäinen <pasik@xxxxxx> wrote:
> On Mon, Apr 12, 2010 at 04:40:49PM +0100, Andrew Lyon wrote:
>> On Mon, Apr 12, 2010 at 12:27 PM, Guillaume Rousse
>> <Guillaume.Rousse@xxxxxxxx> wrote:
>> > Le 10/04/2010 14:58, Pasi Kärkkäinen a écrit :
>> >>> Have you been successful building the drivers for .31 or .32?
>> > I just tried 2.6.33 so far, without success.
>> >
>> >>> I'd like to make a set of patches available to apply to Xen 3.4.2 or
>> >>> 4.0 to enable building the drivers with recent kernels and the forward
>> >>> ported kernels I usually use, but while I've been able to rebuild them
>> >>> on a opensuse 11.2 system running 2.6.31.12 I am finding it hard to
>> >>> work out which patches need to be applied and what else the rpm build
>> >>> process does to enable compilation.
>> >>>
>> >>> Any pointers would be much appreciated.
>> >>>
>> >>
>> >> Did you take a look at novell's sles11 sp1 kernel? it's 2.6.32 and
>> >> should have pv-on-hvm drivers included?
>> > Yes, that's Jan Beulich said on this list. However, I've buid a
>> > 2.6.32.11 kernel, with all xen patches available from SLE11-SP1 (as well
>> > as a few others needed for applying xen patches properly), and used the
>> > corresponding defconfig file. But I can't find any reference to those
>> > drivers, at least with the names given in README file of xen tarball
>> > (xen-platform-pci.ko, xen-vbd.ko, xen-vnif.ko and xen-balloon.ko).
>> > That's probably just because of a name change.
>> >
>> > Anyway (unless I'm wrong), the actual usefulness of pv-on-hvm is on
>> > standard linux kernels, not on dom0 itself, and the issue seems to be on
>> > xen Makefile side.
>> > --
>>
>> I've been looking at this over the weekend and I've made some
>> progress, you are correct about the usefulness of the pv-on-hvm
>> drivers, however you need to bear in mind that the openSUSE/SLES11
>> kernels *always* include the xen patches even if they are not
>> activated for a particular kernel flavour (e.g. desktop, debug etc),
>> so there are some differences in how the drivers are built,
>> specifically the build process uses header files from the xenified
>> kernel instead of from Xen itself.
>>
>> You will not find the pv-on-hvm drivers in the kernel configuration
>> options of any xenified kernel, they are built separately as part of
>> Xen, I decided to have a look at 2.6.31 so I downloaded the latest Xen
>> source rpm for openSUSE 11.2
>> (http://download.opensuse.org/source/distribution/11.2/repo/oss/suse/src/xen-3.4.1_19718_04-2.1.src.rpm),
>> you need to extract the contents of the rpm, then extract the
>> xen-3.4.1-testing-src.tar.bz2, then you need to apply the same patches
>> that the rpm build process would apply, you can work out which patches
>> by reading xen.spec or by running rpmbuild -bb xen.spec on a opensuse
>> system and logging the console output during the build process, then
>> parsing the log for patch commands and running them on the extracted
>> xen source tree.
>>
>
> There also the "-bp" option for rpmbuild:
>
> -bp Executes the "%prep" stage from the spec file.
> Normally this involves unpacking the sources and applying any patches.
>
Noted, that will save time in future :).
>
>
>> The unmodified_drivers build process is designed to work with a
>> separate kernel "objects" folder, so instead of configuring and
>> compiling your kernel in-place you need to do something like this,
>> note that while this step uses a xenified kernel you should not enable
>> Xen in the processor type options, configure the kernel as you would
>> for the hvm guest.
>>
>> cd /usr/src/linux-2.6.31-xen-r14
>> mkdir ../linux-2.6.31-xen-r14-obj
>> mv .config ../linux-2.6.31-xen-r14-obj/ (or copy in your usual default
>> config file)
>> make mrproper
>> cd ../linux-2.6.31-xen-r14-obj/
>> make -C /usr/src/linux-2.6.31-xen-r14 menuconfig
>> O=/usr/src/linux-2.6.31-xen-r14-obj/
>> make -C /usr/src/linux-2.6.31-xen-r14 bzImage (or vmlinuz) modules
>> modules_install O=/usr/src/linux-2.6.31-xen-r14-obj/
>>
>> Now change to wherever you put the unmodified_drivers/linux-2.6/:
>>
>> export XL=/usr/src/linux-2.6.31-xen-r14
>> export XEN=/usr/src/linux-2.6.31-xen-r14/include/xen/
>>
>> Notice how XEN is set to linux/include/xen ? the Xen documentation
>> states that it should be set to a folder containing the Xen sources,
>> I've tried that and it does not work, I think the folder is only used
>> for header files so they could in theory come from Xen or from a
>> Xenified kernel, but on openSUSE the kernel include files are used
>> instead of the Xen ones, and that is the only way that seems to work.
>>
>> ./mkbuildtree
>> Defaulting to this machine's architecture, x86_64, for linking.
>> This may be overridden on the command line (i386,x86_64,ia64).
>> Xen tree: /usr/src/linux-2.6.31-xen-r14/include/xen
>> Linux tree: /usr/src/linux-2.6.31-xen-r14
>>
>> You can now compile the drivers:
>>
>> make -C /usr/src/linux-2.6.31-xen-r14-obj/ modules M=$PWD
>>
>> If you attempt to do the same process without putting the kernel
>> object files into a separate folder the build will fail, I believe
>> this is because declarations in the kernel override those in the
>> unmodified_drivers.
>>
>> Likewise the process fails if you try to use a generic kernel source
>> tree which has not been patched for Xen dom0, in which case the header
>> files are missing various Xen declarations required for successful
>> compilation.
>>
>> And here is a final proof, Xenified 2.6.31 with all XEN options
>> disabled, with pv-on-hvm drivers:
>>
>> localhost ~ # uname -a
>> Linux localhost 2.6.31-xen-r14 #2 SMP Mon Apr 12 13:34:27 GMT 2010
>> x86_64 Intel(R) Xeon(R) CPU E5420 @ 2.50GHz GenuineIntel GNU/Linux
>> localhost ~ # zgrep XEN /proc/config.gz
>> # CONFIG_X86_64_XEN is not set
>> localhost ~ # lsmod
>> Module Size Used by
>> xen_vnif 28288 0
>> xen_balloon 14496 1 xen_vnif
>> xen_vbd 19084 3
>> xen_platform_pci 78808 3 xen_vnif,xen_balloon,xen_vbd,[permanent]
>>
>> I'm not sure where to go next with this but I hope this info is useful.
>>
>
> Congratulations!
>
> This is valuable information, thanks for going through that.
>
> Can you reproduce this with Xen 4.0.0 ? ie. does opensuse xen have
> some patches related to pv-on-hvm drivers?
I believe SLES11SP1 will have Xen 4.0 but I have been unable to find
anywhere to download srpms, apparently they are on dvd2 but as it is
still in beta there are no iso images either, however opensuse factory
does have a Xen 4.0 srpm:
http://download.opensuse.org/factory/repo/src-oss/suse/src/xen-4.0.0_20978_01-1.4.src.rpm
So the same process could be followed using that, I'm going to give it
a try tomorrow.
>
> If there are some patches, those should be upstreamed to Xen.
Hmm, the patches may simply be there to allow building using the
/usr/src/linux/include/xen headers instead of /usr/src/xen/ , and as
xensource does not have a newer "classic" kernel than 2.6.18 why would
they upsteam them.
>
> Also we could try to make the compilation process easier.. somehow.
Indeed :).
>
> -- Pasi
>
>
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