What is the range of the values for vcpu_index given to callbacks, such as:
typedef void (*qemu_plugin_vcpu_udata_cb_t)(unsigned int vcpu_index, void *userdata);
Empirically, when QEMU is in system mode, the maximum vcpu_index is 1 less than the -smp cpus=$(NCPUS) value.
Empirically, when QEMU is in user mode, the values for vcpu_index slowly increase without an apparent upper bound known statically (or when the plugin is loaded?).
Robert Henry