On Mon, Dec 14, 2015 at 03:44:06PM -0200, Eduardo Habkost wrote: > On Thu, Dec 10, 2015 at 11:45:43AM +0530, Bharata B Rao wrote: > > Move back the setting of apic_id to instance_init routine (x86_cpu_initfn) > > This is needed to initialize X86 CPUs using generic cpu-package device. > > Could you explain where exactly apic_id will be used, to make it > necessary to initialize it earlier?
There is a check in x86_cpu_realizefn() to see if apic_id has been initialized properly. Hence I thought x86 target will require apic_id to have been initialized before CPU realization and that is what the existing code does via pc_cpus_init() and pc_new_cpu(). i.e., apic_id property is set before setting the realize property to true. However... > > > > > TODO: I am not fully aware of the general direction in which apic_id > > changes in X86 have evolved and hence not sure if this is indeed aligned > > with > > the X86 way of doing things. This is just to help the PoC implementation > > that I have in this patchset to convert PC CPUs initialization into > > cpu-package device based initialization. > > You shouldn't initialize apic_id on initfn. APIC ID depends (and > will depend) on different CPU properties related to topology, > including (but not limited to) CPU index and CPU topology > properties we may introduce in the future, so it should be done > later (at realize time), not on initfn. ... with the current patchset, I just experimented now by moving the setting of apic_id to x86_cpu_realizefn() and things work just fine. I was in fact pleasantly surprised to see that I could hot add a cpu core by hot plugging the cpu-core device on x86 too. > > Also, cpu_index is initialized by cpu_exec_init(), and > cpu_exec_init() must not be called by initfn. The cpu_exec_init() > call should (and will) be moved to realize in x86 and all other > architectures. Right, I have already moved cpu_exec_init() call to realizefn for PowerPC. Regards, Bharata.
