[Libvirt-cim] ProcRASD VirtualQuantity Field issue for KVM on F10.

[Kaitlin Rupert]

Deepti B Kalakeri wrote:
> Hi,
> 
> The VirtualQuantity field of the ProcRASD is not getting set properly in 
> case of a *running* KVM guest on F10 with the libvirt-0.5.0-1.fc10.x86_64.
> While this is not the case for running KVM guest on F9 with 
> libvirt-0.4.4-2.fc9.x86_64. Also, there is no problem with a *running* 
> Xen guest.

This doesn't happen with F9 because the domain_vcpu_count() doesn't 
exist in the 0.5.1-5 version of the providers.

> 
> The following is the error message in the KVM debug output:
> 
> libvir: Domain error : invalid argument in virDomainGetVcpus
> libvir: Domain error : invalid argument in virDomainGetVcpus
> 
> This is coming from the call to virDomainGetVcpus() from the 
> domain_vcpu_count() function defined in libxkutil/misc_util.c file.
> I verified the signature of the virDomainGetVcpus() with the one given 
> on libvirt.org and it matches.
> 
> The problem is only when the guest is started, else for the defined 
> guest the VirtualQuantity field of the ProcRASD  is set to the vcpu 
> value used.
> 
> I am not sure if this is expected behavior for KVM only or if Xen guest 
> should also behave in the same way, or is it a probable regression in 
> the latest libvirt library on F10.
> I suspect the libvirt library though. Any thoughts ???
> 

I tracked the issue down on a F10 system (with libvirt-0.6.0-3).  We are 
passing NULL for the cpumaps parameter:

      count = virDomainGetVcpus(dom, info, max, NULL, 0);

but libvirt receives a non-NULL value.  This causes the following check 
in virDomainGetVcpus() to fail:

     if (cpumaps != NULL && maplen < 1) {

However, I'm not sure why libvirt is receiving a non-NULL value when 
we're clearly sending NULL...  I'm following up with the libvirt team.

-- 
Kaitlin Rupert
IBM Linux Technology Center
kaitlin at linux.vnet.ibm.com