Re: [PATCH 2/3] hw/smbios: Fix thread count in type4

[Ani Sinha <anisinha@redhat.com>]

On Tue, 30 May 2023, Zhao Liu wrote:

> From: Zhao Liu <zhao1.liu@intel.com>
>
> From SMBIOS 3.0 specification, thread count field means:
>
> Thread Count is the total number of threads detected by the BIOS for
> this processor socket. It is a processor-wide count, not a
> thread-per-core count. [1]
>
> So here we should use threads per socket other than threads per core.
>
> [1] SMBIOS 3.0.0, section 7.5.8, Processor Information - Thread Count

I see two patches sent out around this fix. The patch
[PATCH] hw/smbios: fix thead count field in type 4 table

looks correct to me. I NACK this patch.

>
> Fixes: c97294ec1b9e ("SMBIOS: Build aggregate smbios tables and entry point")
> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
> ---
>  hw/smbios/smbios.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
> index d67415d44dd8..f80a701cdfc1 100644
> --- a/hw/smbios/smbios.c
> +++ b/hw/smbios/smbios.c
> @@ -713,6 +713,7 @@ static void smbios_build_type_4_table(MachineState *ms, unsigned instance)
>  {
>      char sock_str[128];
>      size_t tbl_len = SMBIOS_TYPE_4_LEN_V28;
> +    unsigned cpus_per_socket = ms->smp.max_cpus / ms->smp.sockets;
>

This is confusing. Looking at machine_parse_smp_config(), this is
essentially total number of threads per socket. Maybe a better naming is
threads_per_socket.

Regardless, this patch is confusing.

>      if (smbios_ep_type == SMBIOS_ENTRY_POINT_TYPE_64) {
>          tbl_len = SMBIOS_TYPE_4_LEN_V30;
> @@ -750,14 +751,14 @@ static void smbios_build_type_4_table(MachineState *ms, unsigned instance)
>      t->core_count = (ms->smp.cores > 255) ? 0xFF : ms->smp.cores;
>      t->core_enabled = t->core_count;
>
> -    t->thread_count = (ms->smp.threads > 255) ? 0xFF : ms->smp.threads;
> +    t->thread_count = (cpus_per_socket > 255) ? 0xFF : cpus_per_socket;
>
>      t->processor_characteristics = cpu_to_le16(0x02); /* Unknown */
>      t->processor_family2 = cpu_to_le16(0x01); /* Other */
>
>      if (tbl_len == SMBIOS_TYPE_4_LEN_V30) {
>          t->core_count2 = t->core_enabled2 = cpu_to_le16(ms->smp.cores);
> -        t->thread_count2 = cpu_to_le16(ms->smp.threads);
> +        t->thread_count2 = cpu_to_le16(cpus_per_socket);
>      }
>
>      SMBIOS_BUILD_TABLE_POST;
> --
> 2.34.1
>
>