Re: [Xen-API] Building dom0 kernel modules

[Arjen <arjenvanweelden@xxxxxxxxx>]

On 20-09-13 09:56, Sayid Munawar wrote:
> I once build custom kernel 2.6.32 driver inside xenserver using steps
> described in this page:
>
> http://wiki.xen.org/wiki/Compiling_Kernel_2.6.32
>
> --
> Sayid Munawar
> Sent with Sparrow <http://www.sparrowmailapp.com/?sig>
Thanks for your help. Getting the correct kernel sources from 
XS62E004.zip and using the latest XenServer 6.2 DDK did the trick.
I used the following commands to build the sound modules on the DDK:
 VERSION=`uname -r`
 rpm2cpio /root/kernel-${VERSION}.src.rpm | cpio -idmv
 tar jxf linux-${VERSION}.tar.bz2
 cd linux-${VERSION}
 cp ../kernel-${VERSION}-i686-xen.config .config
 cp /usr/src/kernels/${VERSION}xen-i686/Module.symvers .
 make oldconfig
 echo Enable snd-hda-intel module + RealTek codecs
 make menuconfig
 make prepare
 make scripts
 make M=sound
I hope this will help other people who want to build "default" Linux 
kernel modules for their XenServer.
I copied the resulting sound directory from the DDK to the
/lib/modules/${VERSION}/kernel/ directory on the dom0.
After a depmod -a, modprobe snd-hda-intel worked for me even though it 
did give some errors. I might further investigate the error and 
determine what to actually copy from the sound directory later.
PCI pass-trough of the following device worked fine afterwards:
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset 
Family High Definition Audio Controller (rev 04)
Subsystem: ASRock Incorporation Device 8892
Kernel modules: snd-hda-intel

I still wonder why the driver cannot initialize the device correctly 
from the domU, but can do it from the dom0. Maybe BIOS strings (which I 
did copy when creating the HVM) or something else?
No more audio problems in my Linux domU! (until the next kernel update)

kind regards, Arjen

> On Friday, 20 September 2013 at 4:45 AM, Arjen wrote:
>
> > Hi,
> >
> > I can PCI pass-through my Intel HDA audio controller to a Linux HVM domU
> > as part of virtualizing my desktop. Unfortunately, the audio is
> > stuttering and noisy (ALSA underruns) and I haven't been able to find
> > the right snd_hda_intel module settings to resolve this.
> >
> > The work-around that I found for Xen 4.2 (Gentoo) and KVM (Proxmox) was
> > to let the dom0 initialize the device once by loading the snd_hda_intel
> > kernel module, before releasing the device to pciback/pcistub and
> > starting the the domU with PCI pass-through.
> >
> > However, I cannot use the same trick on XenServer 6.2 because the dom0
> > does not provide the snd_hda_intel kernel model (and it dependencies).
> > I appreciate that sound modules are not usually part of XenServer, but I
> > don't know how else to solve my problem. (Pointers to the right list or
> > forum to ask about this are also very welcome as I can find little
> > information about audio pass-through or snd_hda_intel in a domU.)
> >
> > I found information on building XenServer dom0 kernel modules using the
> > DDK but I'm not sure where to find the source for the latest dom0 kernel
> > sound modules. I looks to me that they are also not included in the
> > XenServer 6.2.0(+XS62E004) dom0 kernel sources RPM, but I might be
> > mistaken?
> >
> > Can someone point me in the right direction for the relevant sources and
> > how to compile them? If you have already compiled (other) "standard but
> > not distributed" kernel modules for XenServer, can you please share your
> > experience?
> >
> > kind regards, Arjen
> >
> > _______________________________________________
> > Xen-api mailing list
> > Xen-api@xxxxxxxxxxxxx <mailto:Xen-api@xxxxxxxxxxxxx>
> > http://lists.xen.org/cgi-bin/mailman/listinfo/xen-api
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