Re: [PATCH v6 10/13] i386: Check for apic id encoding

[Babu Moger]

On 3/11/20 7:17 AM, Igor Mammedov wrote:
> On Tue, 10 Mar 2020 21:34:25 -0500
> Babu Moger <address@hidden> wrote:
> 
>> Check X86CPUDefinition if use_epyc_apic_id_encoding is enabled. If enabled
>> update X86MachineState with EPYC mode apic_id encoding handlers.
>>
>> Also update the calling convention to use apic_id handlers from 
>> X86MachineState.
>>
>> Signed-off-by: Babu Moger <address@hidden>
>> Acked-by: Michael S. Tsirkin <address@hidden>
> usually tags are not retained in case patch is changed significantly
> 
Ok.

> see more below
> 
>> ---
>>  hw/i386/pc.c      |    6 +++---
>>  hw/i386/x86.c     |   32 +++++++++++++++++++++++++++-----
>>  target/i386/cpu.c |   11 +++++++++++
>>  target/i386/cpu.h |    1 +
>>  4 files changed, 42 insertions(+), 8 deletions(-)
>>
>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>> index 98ee763f68..2d7d611184 100644
>> --- a/hw/i386/pc.c
>> +++ b/hw/i386/pc.c
>> @@ -1580,14 +1580,14 @@ static void pc_cpu_pre_plug(HotplugHandler 
>> *hotplug_dev,
>>          topo_ids.die_id = cpu->die_id;
>>          topo_ids.core_id = cpu->core_id;
>>          topo_ids.smt_id = cpu->thread_id;
>> -        cpu->apic_id = x86_apicid_from_topo_ids(&topo_info, &topo_ids);
>> +        cpu->apic_id = x86ms->apicid_from_topo_ids(&topo_info, &topo_ids);
>>      }
>>  
>>      cpu_slot = pc_find_cpu_slot(MACHINE(pcms), cpu->apic_id, &idx);
>>      if (!cpu_slot) {
>>          MachineState *ms = MACHINE(pcms);
>>  
>> -        x86_topo_ids_from_apicid(cpu->apic_id, &topo_info, &topo_ids);
>> +        x86ms->topo_ids_from_apicid(cpu->apic_id, &topo_info, &topo_ids);
>>          error_setg(errp,
>>              "Invalid CPU [socket: %u, die: %u, core: %u, thread: %u] with"
>>              " APIC ID %" PRIu32 ", valid index range 0:%d",
>> @@ -1608,7 +1608,7 @@ static void pc_cpu_pre_plug(HotplugHandler 
>> *hotplug_dev,
>>      /* TODO: move socket_id/core_id/thread_id checks into 
>> x86_cpu_realizefn()
>>       * once -smp refactoring is complete and there will be CPU private
>>       * CPUState::nr_cores and CPUState::nr_threads fields instead of 
>> globals */
>> -    x86_topo_ids_from_apicid(cpu->apic_id, &topo_info, &topo_ids);
>> +    x86ms->topo_ids_from_apicid(cpu->apic_id, &topo_info, &topo_ids);
>>      if (cpu->socket_id != -1 && cpu->socket_id != topo_ids.pkg_id) {
>>          error_setg(errp, "property socket-id: %u doesn't match set apic-id:"
>>              " 0x%x (socket-id: %u)", cpu->socket_id, cpu->apic_id,
>> diff --git a/hw/i386/x86.c b/hw/i386/x86.c
>> index 7dc237c014..ad85347142 100644
>> --- a/hw/i386/x86.c
>> +++ b/hw/i386/x86.c
>> @@ -68,6 +68,25 @@ inline void init_topo_info(X86CPUTopoInfo *topo_info,
>>      topo_info->threads_per_core = ms->smp.threads;
>>  }
>>  
>> +/*
>> + * Check for APIC ID encoding
>> + *
>> + * AMD uses different apic id encoding for their EPYC based cpus.
>> + * Check if we need to use different handlers than the default.
> comment is not valid, cpu_x86_use_epyc_apic_id_encoding() does the checking
> but this function actually overrides it.
> 
> it would be better to name it properly and amend comment, something like
> 
> if (cpu_x86_use_epyc_apic_id_encoding(machine->cpu_type)) {
>    set_epyc_topo_handlers()
> }

Ok. Will fix it. I will move the assignment to new function
set_epyc_topo_handlers() and fix the comment.

> 
>> + */
>> +static void x86_check_apic_id_encoding(MachineState *machine)
>> +{
>> +    X86MachineState *x86ms = X86_MACHINE(machine);
>> +
>> +    if (cpu_x86_use_epyc_apic_id_encoding(machine->cpu_type)) {
>> +        x86ms->apicid_from_cpu_idx = x86_apicid_from_cpu_idx_epyc;
>> +        x86ms->topo_ids_from_apicid = x86_topo_ids_from_apicid_epyc;
>> +        x86ms->topo_ids_from_idx = x86_topo_ids_from_idx_epyc;
>> +        x86ms->apicid_from_topo_ids = x86_apicid_from_topo_ids_epyc;
>> +        x86ms->apicid_pkg_offset = apicid_pkg_offset_epyc;
>> +    }
>> +}
>> +
>>  /*
>>   * Calculates initial APIC ID for a specific CPU index
>>   *
>> @@ -86,7 +105,7 @@ uint32_t x86_cpu_apic_id_from_index(X86MachineState 
>> *x86ms,
>>  
>>      init_topo_info(&topo_info, x86ms);
>>  
>> -    correct_id = x86_apicid_from_cpu_idx(&topo_info, cpu_index);
>> +    correct_id = x86ms->apicid_from_cpu_idx(&topo_info, cpu_index);
>>      if (x86mc->compat_apic_id_mode) {
>>          if (cpu_index != correct_id && !warned && !qtest_enabled()) {
>>              error_report("APIC IDs set in compatibility mode, "
>> @@ -158,8 +177,8 @@ int64_t x86_get_default_cpu_node_id(const MachineState 
>> *ms, int idx)
>>     init_topo_info(&topo_info, x86ms);
>>  
>>     assert(idx < ms->possible_cpus->len);
>> -   x86_topo_ids_from_apicid(ms->possible_cpus->cpus[idx].arch_id,
>> -                            &topo_info, &topo_ids);
>> +   x86ms->topo_ids_from_apicid(ms->possible_cpus->cpus[idx].arch_id,
>> +                               &topo_info, &topo_ids);
>>     return topo_ids.pkg_id % ms->numa_state->num_nodes;
>>  }
>>  
>> @@ -179,6 +198,9 @@ const CPUArchIdList 
>> *x86_possible_cpu_arch_ids(MachineState *ms)
>>          return ms->possible_cpus;
>>      }
>>  
>> +    /* Check for apicid encoding */
>> +    x86_check_apic_id_encoding(ms);
> 
> that might crash if user used legacy -numa node,cpus= option
> option parser would call reach here before machine->cpu_type is set
> 
> it's better to put this call into x86_cpus_init() like it was done
> in previous versions

I have tested with legacy -numa option. It works fine. I can remove this
call from here but I need to call the function x86_topo_ids_from_apicid(or
x86_topo_ids_from_idx) directly. I cannot use the callback here(because
x86_cpus_init has not happened at this point). Is that fine?


> 
>>      ms->possible_cpus = g_malloc0(sizeof(CPUArchIdList) +
>>                                    sizeof(CPUArchId) * max_cpus);
>>      ms->possible_cpus->len = max_cpus;
>> @@ -192,8 +214,8 @@ const CPUArchIdList 
>> *x86_possible_cpu_arch_ids(MachineState *ms)
>>          ms->possible_cpus->cpus[i].vcpus_count = 1;
>>          ms->possible_cpus->cpus[i].arch_id =
>>              x86_cpu_apic_id_from_index(x86ms, i);
>> -        x86_topo_ids_from_apicid(ms->possible_cpus->cpus[i].arch_id,
>> -                                 &topo_info, &topo_ids);
>> +        x86ms->topo_ids_from_apicid(ms->possible_cpus->cpus[i].arch_id,
>> +                                    &topo_info, &topo_ids);
>>          ms->possible_cpus->cpus[i].props.has_socket_id = true;
>>          ms->possible_cpus->cpus[i].props.socket_id = topo_ids.pkg_id;
>>          if (x86ms->smp_dies > 1) {
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index a3051524a2..19de79d01c 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -1615,6 +1615,10 @@ typedef struct X86CPUDefinition {
>>      FeatureWordArray features;
>>      const char *model_id;
>>      CPUCaches *cache_info;
>> +
>> +    /* Use AMD EPYC encoding for apic id */
>> +    bool use_epyc_apic_id_encoding;
>> +
>>      /*
>>       * Definitions for alternative versions of CPU model.
>>       * List is terminated by item with version == 0.
>> @@ -1656,6 +1660,13 @@ static const X86CPUVersionDefinition 
>> *x86_cpu_def_get_versions(X86CPUDefinition
>>      return def->versions ?: default_version_list;
>>  }
>>  
>> +bool cpu_x86_use_epyc_apic_id_encoding(const char *cpu_type)
>> +{
>> +    X86CPUClass *xcc = X86_CPU_CLASS(object_class_by_name(cpu_type));
> 
> assert(xcc)

will add and I need to check for cpudef also.

> 
>> +
>> +    return xcc->model->cpudef->use_epyc_apic_id_encoding;
>> +}
>> +
>>  static CPUCaches epyc_cache_info = {
>>      .l1d_cache = &(CPUCacheInfo) {
>>          .type = DATA_CACHE,
>> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
>> index 7e9e963d78..6e522fcd34 100644
>> --- a/target/i386/cpu.h
>> +++ b/target/i386/cpu.h
>> @@ -1897,6 +1897,7 @@ void cpu_clear_apic_feature(CPUX86State *env);
>>  void host_cpuid(uint32_t function, uint32_t count,
>>                  uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx);
>>  void host_vendor_fms(char *vendor, int *family, int *model, int *stepping);
>> +bool cpu_x86_use_epyc_apic_id_encoding(const char *cpu_type);
>>  
>>  /* helper.c */
>>  bool x86_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
>>
>