[libvirt] Developing libvirt for virtual devices like virtual printers

Hi, I have a couple of questions. - I am a new libvirt code developer. I have just cloned the repo and I am looking for a suitable debugger/IDE which will help me debug the code. - I work in developing and creating virtual printers with display, with QEMU as the hypervisor (no KVM-only Qemu). Currently we have our own application to manage the virtual printers. Our plan is to migrate to libvirt, and enable our application to use the libvirt APIs. libvirt code currently looks to be specialized in pure OS-specific guests (like PCs), and I hit snags where there are manadatory devices added which a virtual printer does not need. Are there any developers who are looking into customized virtual devices? I would like to knowledge share with them. The intention is to provide new libvirt APIs whenever there is such a snag and thus enable libvirt to be used for managing virtual printers. - One issue that we are seeing is with regard to USB Host Controller: We have a customized model of ehci USB Host Controller (named nr52_ehci_usb) in qemu (locally built). When I add the custom value (n552_ehci_usb) of the host controller as the "model" type in my dom xml, virsh define <xml> fails with invalid model type error. I remove the usb controller entry from the xml, and add "-usb" as a "qemucommandline" parameter, but then libvirt adds the device lsi (-device lsi,id=scsi0 -usb), and the virsh create command fails with: "-device lsi,id=scsi0 No PCI bus found for lsi53c895a". The board we have created in QEMU does not have PCI bus implemented. I am interested in the code related to host controllers. Is there any way I can get my usb host controller to be recognized by libvirt? Is there a way I can prevent lsi device from getting added when I make -usb a qemu command line parameter? Regards, Deepti