On Mon, 3 Feb 2020 15:49:31 -0600 Babu Moger <[email protected]> wrote:
> On 2/3/20 9:17 AM, Igor Mammedov wrote: > > On Wed, 29 Jan 2020 10:17:11 -0600 > > Babu Moger <[email protected]> wrote: > > > >> On 1/29/20 3:14 AM, Igor Mammedov wrote: > >>> On Tue, 28 Jan 2020 13:45:31 -0600 > >>> Babu Moger <[email protected]> wrote: > >>> > >>>> On 1/28/20 10:29 AM, Igor Mammedov wrote: > >>>>> On Tue, 03 Dec 2019 18:37:42 -0600 > >>>>> Babu Moger <[email protected]> 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 <[email protected]> > >>>>>> --- > >>>>>> 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? > >> > >> > >> The current code(before this series) parses the numa information and then > >> sequentially builds the apicid. Both are done together. > >> > >> But this series separates the numa parsing and apicid generation. Numa > >> parsing is done first and after that the apicid is generated. Reason is we > >> need to know the number of numa nodes in advance to decode the apicid. > >> > >> Look at this patch. > >> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fqemu-devel%2F157541988471.46157.6587693720990965800.stgit%40naples-babu.amd.com%2F&data=02%7C01%7Cbabu.moger%40amd.com%7C0a643dd978f149acf9d108d7a8bc487a%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637163398941923379&sdata=sP2TnNaqNXRGEeQNhJMna3wyeBqN0XbNKqgsCTVDaOQ%3D&reserved=0 > >> > >> static inline apic_id_t apicid_from_topo_ids_epyc(X86CPUTopoInfo > >> *topo_info, > >> + const X86CPUTopoIDs > >> *topo_ids) > >> +{ > >> + return (topo_ids->pkg_id << apicid_pkg_offset_epyc(topo_info)) | > >> + (topo_ids->llc_id << apicid_llc_offset_epyc(topo_info)) | > >> + (topo_ids->die_id << apicid_die_offset(topo_info)) | > >> + (topo_ids->core_id << apicid_core_offset(topo_info)) | > >> + topo_ids->smt_id; > >> +} > >> > >> > >> The function apicid_from_topo_ids_epyc builds the apicid. New decode adds > >> llc_id(which is numa id here) to the current decoding. Other fields are > >> mostly remains same. > > > > If llc_id is the same as numa id, why not reuse > > CpuInstanceProperties::node-id > > instead of llc_id you are adding in previous patch 6/18? > > > I tried to use that earlier. But dropped the idea as it required some > changes. Don't remember exactly now. I am going to investigate again if we > can use the node_id for our purpose here. Will let you know if I have any > issues. The reason I'm asking to not add new properties here is that it expands interface visible/used by management tools and it's maintenance burden not only on QEMU but on engagement side as well. So if yo can reuse node-id, it will work out of box with existing users. It should also be less confusing for us since we don't have to keep in mind (or figure out) that llc_id is the same as node id and wonder why the later wasn't used in the first place.
