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

Jan Kiszka
2011-08-30T20:00:09Z

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On 2011-08-30 21:39, Chris Friesen wrote:
> 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.

That's at least how recent vanilla kernels work. I think to remember
that my old OpenSUSE 11.1 (2.6.27) used to work fine with kvm-kmod as
well, and that was an out-of-tree setup too (but maybe a post-processed
one).

Anyway, if you have some patch to fix this, it will always be welcome.

>
> 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.

If CONFIG_PROFILING is off, prof_on is defined to 0. But we may miss
some include on older kernels. Does adding linux/profile.h to x86.c
solve the issue as well?

Jan

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