Re: [PATCH v3 07/18] machine: Add a new function init_apicid_fn in MachineClass

[Eduardo Habkost]

On Wed, Jan 29, 2020 at 10:32:01AM -0600, Babu Moger wrote:
> 
> 
> On 1/29/20 3:14 AM, Igor Mammedov wrote:
> > On Tue, 28 Jan 2020 13:45:31 -0600
> > Babu Moger <address@hidden> wrote:
> > 
> >> On 1/28/20 10:29 AM, Igor Mammedov wrote:
> >>> On Tue, 03 Dec 2019 18:37:42 -0600
> >>> Babu Moger <address@hidden> wrote:
> >>>   
> >>>> Add a new function init_apicid_fn in MachineClass to initialize the mode
> >>>> specific handlers to decode the apic ids.
> >>>>
> >>>> Signed-off-by: Babu Moger <address@hidden>
> >>>> ---
> >>>>  include/hw/boards.h |    1 +
> >>>>  vl.c                |    3 +++
> >>>>  2 files changed, 4 insertions(+)
> >>>>
> >>>> diff --git a/include/hw/boards.h b/include/hw/boards.h
> >>>> index d4fab218e6..ce5aa365cb 100644
> >>>> --- a/include/hw/boards.h
> >>>> +++ b/include/hw/boards.h
> >>>> @@ -238,6 +238,7 @@ struct MachineClass {
> >>>>                                                           unsigned 
> >>>> cpu_index);
> >>>>      const CPUArchIdList *(*possible_cpu_arch_ids)(MachineState 
> >>>> *machine);
> >>>>      int64_t (*get_default_cpu_node_id)(const MachineState *ms, int idx);
> >>>> +    void (*init_apicid_fn)(MachineState *ms);  
> >>> it's x86 specific, so why it wasn put into PCMachineClass?  
> >>
> >> Yes. It is x86 specific for now. I tried to make it generic function so
> >> other OSes can use it if required(like we have done in
> >> possible_cpu_arch_ids). It initializes functions required to build the
> >> apicid for each CPUs. We need these functions much early in the
> >> initialization. It should be initialized before parse_numa_opts or
> >> machine_run_board_init(in v1.c) which are called from generic context. We
> >> cannot use PCMachineClass at this time.
> > 
> > could you point to specific patches in this series that require
> > apic ids being initialized before parse_numa_opts and elaborate why?
> > 
> > we already have possible_cpu_arch_ids() which could be called very
> > early and calculates APIC IDs in x86 case, so why not reuse it?
> 
> Forgot to respond to this. The possible_cpu_arch_ids does not use the numa
> information to build the apic id. We cannot re-use it without changing it
> drastically.

I don't get it.  I see multiple patches in this series changing
pc_possible_cpu_arch_ids() (which is really expected, if you are
changing how APIC IDs are generated).

-- 
Eduardo