On 09/01/20 12:23, Philippe Mathieu-Daudé wrote: > > > current_machine = > MACHINE(object_new_with_class(OBJECT_CLASS(machine_class))); > object_property_add_child(object_get_root(), "machine", > OBJECT(current_machine), &error_abort); > > The bigger user of 'current_machine' is the accel/KVM code. > > Recently in a0628599f..cc7d44c2e0 "Replace global smp variables with > machine smp properties" we started to use MACHINE(qdev_get_machine()). > > qdev_get_machine() resolves the machine in the QOM composition tree. > I am confused by this comment: > > /* qdev_get_machine() can return something that's not TYPE_MACHINE > * if this is one of the user-only emulators; in that case there's > * no need to check the ignore_memory_transaction_failures board flag. > */ > > Following a0628599f..cc7d44c2e0, a5e0b33119 use 'current_machine' again. > > What are the differences between both form, when should we use one or > another (or can we use a single one?). Can this break user-only mode?
I would always use MACHINE(qdev_get_machine()), espeecially outside vl.c. Ideally, current_machine would be static within vl.c or even unused outside the object_property_add_child() that you quote above. Most of the times, I noticed from a quick grep, we actually want to access the accelerator, not the machine, so we could add a qemu_get_accelerator() wrapper that does MACHINE(qdev_get_machine())->accelerator. Paolo
