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

[Igor Mammedov]

On Wed, 11 Mar 2020 09:50:04 -0500
Babu Moger <address@hidden> wrote:

> 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?
That's fine.
x86_topo_ids_from_idx() is the only one that could work correctly early,
since x86_topo_ids_from_idx_epyc() depends on all numa nodes being already 
parsed.

which rises a question do we really need topo_ids_from_idx() callback and 
x86_topo_ids_from_idx_epyc()?
I don't see why it's necessary.

> 
> >   
> >>      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,
> >>  
> >   
>