On 03/19/2015 11:44 AM, Parvathi wrote:

Hi,

I am developing an application that would essentially control/run VMs on a X86_64 host machine. The existing OS is 32 bit based so the application needs to be 32bit too. KVM/QEMU are 64 bit so that guests could be either be 32 or 64 bit. Does using libvirt as 32bit library on a 64bit host (capable of hosting 32 and 64 bit guests) pose any problems? Will it even work?

Yes, a 32-bit libvirt.so client on one host can correctly control a 64-bit libvirtd on another host. There are some APIs that (for historical reasons) pass a 'long'; these APIs properly flag overflow if a value cannot be converted from 64-bit on the host down to the limited 32-bit on the client. But as long as the API doesn't trigger that large of a value, you are fine. And for everything specified as 'int' or 'long long', it all works just fine. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org