[Libvir] Proposal for virtual devices

I previously made a proposal for block devices. It was rejected because it was VBD-specific and Xen-specific. Here is a proposal for transparent interface with Xen or other. The virtual device attributes (VDA) are transferred from/to application without considering their meaning, except backend domain, previously requested to be the name for user, while it is the ID for Xen. typedef struct virVDA { /* virtual device attribute */ char name[16]; char value[64]; } virVDA; int virDomainGetVdevs(virDomainPtr domain, char *type, virVDA *attr, int maxattr); * @type: pointer to device type, "disk", "network" ... * @attr: pointer to an array of virVDA structures * @maxattr: number of structures in attr array * Return: (number of VDAs per device)<<16 + (number of devices), if success; * -1 if failure. For "disk" type, Xen provides the following VDA names: "virtual-device" (virtual device number) "backend-id" (backend domain ID) "state" "backend" (backend device or file) "ring-ref" "event-channel" This function changes "backend-id" to "bkdom-name" and translates value ID into name. int virDomainCreateVdev(virDomainPtr domain, char *type, virVDA *attr, int nbattr); * @type: pointer to device type, "disk", "network" ... * @attr: pointer to an array of virVDA structures * @nbattr: number of structures in attr array For "disk" type, Xen requires the following VDA names: "uname" (backend device, value either "phy:<>" or "file:<>" "dev" (virtual device number) "mode" (value "ro" for read-only, or "rw" for read/write) "backend" (backend domain ID) This function translates "backend" user value (name) into ID. int virDomainDestroyVdev(virDomainPtr domain, char *type, char *ref); * @type: pointer to device type, "disk", "network" ... * @ref: pointer to virtual device reference (number for Xen...)