Re: [PATCH] hw/smbios: fix thead count field in type 4 table

[bibo, mao]

在 2023/6/1 10:26, Zhao Liu 写道:
> On Thu, Jun 01, 2023 at 09:09:13AM +0800, bibo, mao wrote:
> > Date: Thu, 1 Jun 2023 09:09:13 +0800
> > From: "bibo, mao" <maobibo@loongson.cn>
> > Subject: Re: [PATCH] hw/smbios: fix thead count field in type 4 table
> >
> >
> >
> > 在 2023/5/31 16:42, Zhao Liu 写道:
> > > On Tue, May 30, 2023 at 08:20:34PM +0800, Tianrui Zhao wrote:
> > > > Date: Tue, 30 May 2023 20:20:34 +0800
> > > > From: Tianrui Zhao <zhaotianrui@loongson.cn>
> > > > Subject: [PATCH] hw/smbios: fix thead count field in type 4 table
> > > > X-Mailer: git-send-email 2.39.1
> > > >
> > > > The thread_count value in smbios type_4 table should be
> > > > (ms->smp.cores * ms->smp.threads). As according to smbios spec 7.5
> > > > Processor Information (Type 4), the field "Thread Count" means the
> > > > "Number of threads per processor socket" rather than number of
> > > > threads per core.
> > > >
> > > > When apply this patch, use "-smp 4,sockets=1,cores=2,threads=2" to
> > > > boot VM, the dmidecode -t 4 shows like:
> > > >
> > > > Handle 0x0400, DMI type 4, 48 bytes
> > > > Processor Information
> > > >           Socket Designation: CPU 0
> > > >           ...
> > > >           Core Count: 2
> > > >           Core Enabled: 2
> > > >           Thread Count: 4
> > > >           Characteristics: None
> > > >
> > > > Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
> > > > ---
> > > >    hw/smbios/smbios.c | 7 ++++---
> > > >    1 file changed, 4 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
> > > > index d2007e70fb..56aeaa069d 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;
> > > > +    int count;
> > > >        if (smbios_ep_type == SMBIOS_ENTRY_POINT_TYPE_64) {
> > > >            tbl_len = SMBIOS_TYPE_4_LEN_V30;
> > > > @@ -749,15 +750,15 @@ 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;
> > > > +    count = ms->smp.cores * ms->smp.threads;
> > >
> > > Hi Ani & Tianrui,
> > >
> > >   From the comment of CpuTopology (include/hw/boards.h):
> > >
> > > ms->cores means the "the number of cores in one cluster".
> > > ms->threads means the "the number of threads in one core".
> > >
> > > So ms->cores * ms->threads means the number of threads in one cluster
> > > not one socket.
> > >
> > > That's why I count the number of threads in a socket by "ms->smp.max_cpus
> > > / ms->smp.sockets" in [1].
> > >
> > > The other correct way is:
> > > ms->smp.cluster * ms->smp.cores * ms->smp.threads.
> > >
> > > [1]: https://lists.gnu.org/archive/html/qemu-devel/2023-05/msg07229.html
> > ohh, we do not notice your patch. Your patch is better than us. one small
> > nit about core_count calcuation if cluster/die is support. core count should
> > be core number
> >   per package rather than per cluster or per die.
> >
> > so it should be something like this?
> >      t->core_count = cpus_per_socket / ms->smp.threads
> > rather than ms->smp.cores
>
> Yes, I also fixed this in the third patch of my patch series [2].
>
> [2]: https://lists.gnu.org/archive/html/qemu-devel/2023-05/msg07231.html

Great, that sounds good to me.

Regards
Bibo, Mao

> Regards,
> Zhao
>
> > Regards
> > Bibo, mao
> > > Thanks,
> > > Zhao
> > >
> > > > +    t->thread_count = (count > 255) ? 0xFF : count;
> > > >        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(count);
> > > >        }
> > > >        SMBIOS_BUILD_TABLE_POST;
> > > > --
> > > > 2.39.1