Re: [PATCH] target/i386: Fix reporting of CPU dies when nr_cores=nr_threads=1

[Xiaoyao Li <xiaoyao.li@intel.com>]

On 7/24/2023 2:59 AM, 小太 wrote:
> When QEMU is started with `-smp D,sockets=1,dies=D,cores=1,threads=1` (that
> is, 1 socket with D dies but each die contains just a single thread), both
> Linux and Windows guests incorrectly interprets the system as having D
> sockets with 1 die each
> 
> Ultimately this is caused by various CPUID leaves not being die-aware in
> their "threads per socket" calculations, so this patch fixes that
> 
> These changes are referenced to the AMD PPR for Family 19h Model 01h (Milan)
> and Family 17h Model 01h (Naples) manuals:
>   - CPUID_Fn00000001_EBX[23:16]: Number of threads in the processor
>                                  (Core::X86::Cpuid::SizeId[NC] + 1)
>   - CPUID_Fn0000000B_EBX_x01[15:0]: Number of logical cores in processor
>                                     socket (not present until Rome)
>   - CPUID_Fn80000001_ECX[1]: Multi core product
>                              (Core::X86::Cpuid::SizeId[NC] != 0)
>   - CPUID_Fn80000008_ECX[7:0]: The number of threads in the package - 1
>                                (Core::X86::Cpuid::SizeId[NC])
> 
> Note there are two remaining occurences that I didn't touch:
>   - CPUID_Fn8000001E_ECX[10:8]: Always 0 (1 node per processor) for Milan.
>                                 But for Naples, it can also be 2 or 4 nodes
>                                 where each node is defined as one or two
>                                 CCXes (CCD?). But Milan also has multiple
>                                 CCXes, so clearly the definition of a node is
>                                 different from model to model, so I've left
>                                 it untouched. (QEMU seems to use the Naples
>                                 definition)
>   - MSR_CORE_THREAD_COUNT: This MSR doesn't exist on Milan or Naples

Is this patch specific to AMD CPU type? what's situation for Intel CPU?