Problems with kvm-73 on PAE host

Problems with kvm-73 on PAE host

[Bernhard Kohl]

Hi,

I'm trying to run kvm-73 on a Linux PAE host. I'm using Fedora 8 on the host, 
installed kernel-PAE and kernel-PAE-devel (2.6.25.14-69.fc8.i686), built and 
installed KVM:

make distclean
./configure
make
make install

Immediately after starting any VM the following error occurs. Did I miss 
anything? No problems with the non PAE kernels.

kvm_run: failed entry, reason 7
kvm_run returned -8

Re: Problems with kvm-73 on PAE host

[Bernhard Kohl]

Bernhard Kohl <Bernhard.Kohl <at> nsn.com> writes:

> 
> Hi,
> 
> I'm trying to run kvm-73 on a Linux PAE host. I'm using Fedora 8 on the 
host, 
> installed kernel-PAE and kernel-PAE-devel (2.6.25.14-69.fc8.i686), built and 
> installed KVM:
> 
> make distclean
> ./configure
> make
> make install
> 
> Immediately after starting any VM the following error occurs. Did I miss 
> anything? No problems with the non PAE kernels.
> 
> kvm_run: failed entry, reason 7
> kvm_run returned -8

Hi again,

some more infos about this topic:
As I could find out this is an VM-instruction error (VM entry with invalid 
control field(s)). Is this a bug in KVM when running on a PAE kernel? Or are 
there special configuration options necessary for building KVM for a PAE 
kernel.
There is no output in dmesg.

Re: Problems with kvm-73 on PAE host

[Avi Kivity]

Bernhard Kohl wrote:
> Bernhard Kohl <Bernhard.Kohl <at> nsn.com> writes:
>
>   
>> Hi,
>>
>> I'm trying to run kvm-73 on a Linux PAE host. I'm using Fedora 8 on the 
>>     
> host, 
>   
>> installed kernel-PAE and kernel-PAE-devel (2.6.25.14-69.fc8.i686), built and 
>> installed KVM:
>>
>> make distclean
>> ./configure
>> make
>> make install
>>
>>     

Did you remember to reload the modules?  maybe you are using some stale 
modules.

>> Immediately after starting any VM the following error occurs. Did I miss 
>> anything? No problems with the non PAE kernels.
>>
>> kvm_run: failed entry, reason 7
>> kvm_run returned -8
>>     
>
> Hi again,
>
> some more infos about this topic:
> As I could find out this is an VM-instruction error (VM entry with invalid 
> control field(s)). Is this a bug in KVM when running on a PAE kernel? Or are 
> there special configuration options necessary for building KVM for a PAE 
> kernel.
> There is no output in dmesg.
>   

How much memory does the host have?

-- 
error compiling committee.c: too many arguments to function

Re: Problems with kvm-73 on PAE host

[Bernhard Kohl]

Avi Kivity <avi <at> qumranet.com> writes:

> 
> Bernhard Kohl wrote:
> > Bernhard Kohl <Bernhard.Kohl <at> nsn.com> writes:
> >
> >   
> >> Hi,
> >>
> >> I'm trying to run kvm-73 on a Linux PAE host. I'm using Fedora 8 on the 
> >>     
> > host, 
> >   
> >> installed kernel-PAE and kernel-PAE-devel (2.6.25.14-69.fc8.i686), built 
and 
> >> installed KVM:
> >>
> >> make distclean
> >> ./configure
> >> make
> >> make install
> >>
> >>     
> 
> Did you remember to reload the modules?  maybe you are using some stale 
> modules.

Yes of course. Sorry, I forgot this in my description above. I'm doing that 
usually in a little script:

...
modprobe -vr kvm-intel
make install
modprobe -v kvm-intel

> >> Immediately after starting any VM the following error occurs. Did I miss 
> >> anything? No problems with the non PAE kernels.
> >>
> >> kvm_run: failed entry, reason 7
> >> kvm_run returned -8
> >>     
> >
> > Hi again,
> >
> > some more infos about this topic:
> > As I could find out this is an VM-instruction error (VM entry with invalid 
> > control field(s)). Is this a bug in KVM when running on a PAE kernel? Or 
are 
> > there special configuration options necessary for building KVM for a PAE 
> > kernel.
> > There is no output in dmesg.
> >   
> 
> How much memory does the host have?

It has currently 8 GB. The host Linux sees all this memory. We plan to expand 
this to 16 GB and run 4 guests with a legacy 32-bit OS. Is it possible that 
these guest see 3 GB or is there still a 2 GB limit for 32-bit guests on 32-
bit hosts?

I searched a lot about this topic in this mailing list, but I'm not quite sure.

Unfortunately we currently need to use several hosts with CPUs that don't 
support 64-bit. So I got the idea to use the PAE Linux on these hosts.