Re: help? need to enable VT-d for 2.6.27

Chris Friesen
2011-08-30T19:39:28Z

On 08/30/2011 12:31 PM, David Ahern wrote:

> In my case I am setting the MAC address for the VFs in the host at boot;
> they are getting reset on passthrough so the VM driver creates a random
> one. A backport of commit a6b5ea3 fixes one aspect. Looking at the code
> for the igb driver I think commit 8fa7e0f fixes the other reset problem.
>
> On the plus side I can tell you that the VF driver for the VM
> http://sourceforge.net/projects/e1000/files/igbvf%20stable/
>
> compiles cleaning against WRL3 and appears to work fine (limited testing
> with benchmarks).
>
> kernel module wise I ran some basic KVM tests with kvm-kmod-2.6.32.27; I
> have not tried VF passthrough. This is on my radar as well, so I would
> be interested in what you learn.

I downloaded the latest kvm-kmod release. It looks interesting, but it
has some issues:

1) I use separate source and build output directories. kvm-kmod assumes
that there is a "source" link in my build output directory pointing back
to the source directory. This doesn't exist, so the build breaks.

2) If I create such a link, it builds a few files, and then gives the
following:

/home/cfriesen/Download/kvm-kmod-3.0b/x86/x86.c: In function
‘vcpu_enter_guest’:
/home/cfriesen/Download/kvm-kmod-3.0b/x86/x86.c:5539:26: error:
‘prof_on’ undeclared (first use in this function)
/home/cfriesen/Download/kvm-kmod-3.0b/x86/x86.c:5539:26: note: each
undeclared identifier is reported only once for each function it appears in

This appears to be due to the fact that KVM_PROFILING is defined
unconditionally in my kernel, but "prof_on" is only defined if
CONFIG_PROFILING is enabled. Commenting out that chunk of code in x86.c
lets everything build.

I haven't tried actually loading it yet, that will be next.

Thanks for the pointer.
Chris

--
Chris Friesen
Software Developer
GENBAND
chris.friesen@genband.com