vmstate: Make vmstate_register() static inline

This avoids adding a duplicate stub for CONFIG_USER_ONLY.

Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
stubs: Add a vmstate_dummy struct for CONFIG_USER_ONLY

Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
cpu: Register VMStateDescription through CPUState

In comparison to DeviceClass::vmsd, CPU VMState is split in two,
"cpu_common" and "cpu", and uses cpu_index as instance_id instead of -1.
Therefore add a CPU-specific CPUClass::vmsd field.

Unlike the legacy CPUArchState registration, rather register CPUState.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
cpu: Introduce cpu_class_set_vmsd()

This setter avoids redefining each VMStateDescription value to
vmstate_dummy by not referencing the value for CONFIG_USER_ONLY.

Suggested-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: Update VMStateDescription to X86CPU

Expose vmstate_cpu as vmstate_x86_cpu and hook it up to CPUClass::vmsd.
Adapt opaques and VMState fields to X86CPU. Drop cpu_{save,load}().

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>