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

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 10 Mar 2020 21:34:25 -0500
Babu Moger <babu.moger@amd.com> 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 <babu.moger@amd.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
usually tags are not retained in case patch is changed significantly

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()
}

> + */
> +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

>      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)

> +
> +    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,
>