Re: [edk2-devel] [PATCH 1/2] Platform/SbsaQemu: get the information of CPU topology via SMC calls

["Marcin Juszkiewicz" <marcin.juszkiewicz@linaro.org>]

W dniu 17.04.2024 o 13:26, Xiong Yining pisze:
> Provide functions to check for CPU topology information:
> - the number of sockets on sbsa-ref platform.
> - the number of clusters in one socket.
> - the number of cores in one cluster.
> - the number of threads in one cores.
> 
> As SMC calls can return up to 4 return values. the number of
> sockets, clusters and cores are read from TF-A using platform
> specific SMC calls. And the number of threads is caluculated
> using the total number of cpus and the number of sockets,
> clusters and cores.
> 
> Signed-off-by: Xiong Yining <xiongyining1480@phytium.com.cn>
> ---
>   .../Include/IndustryStandard/SbsaQemuSmc.h    |  1 +
>   .../Include/Library/HardwareInfoLib.h         | 26 +++++++++++++++
>   .../SbsaQemuHardwareInfoLib.c                 | 33 +++++++++++++++++++
>   3 files changed, 60 insertions(+)
> 
> diff --git a/Silicon/Qemu/SbsaQemu/Include/IndustryStandard/SbsaQemuSmc.h b/Silicon/Qemu/SbsaQemu/Include/IndustryStandard/SbsaQemuSmc.h
> index e3092007d27d..9d9780ca70fe 100644
> --- a/Silicon/Qemu/SbsaQemu/Include/IndustryStandard/SbsaQemuSmc.h
> +++ b/Silicon/Qemu/SbsaQemu/Include/IndustryStandard/SbsaQemuSmc.h
> @@ -16,6 +16,7 @@
>   #define SIP_SVC_GET_GIC_ITS    SMC_SIP_FUNCTION_ID(101)
>   #define SIP_SVC_GET_CPU_COUNT  SMC_SIP_FUNCTION_ID(200)
>   #define SIP_SVC_GET_CPU_NODE   SMC_SIP_FUNCTION_ID(201)
> +#define SIP_SVC_GET_CPU_TOPOLOGY SMC_SIP_FUNCTION_ID(202)
>   #define SIP_SVC_GET_MEMORY_NODE_COUNT SMC_SIP_FUNCTION_ID(300)
>   #define SIP_SVC_GET_MEMORY_NODE SMC_SIP_FUNCTION_ID(301)
>   
> diff --git a/Silicon/Qemu/SbsaQemu/Include/Library/HardwareInfoLib.h b/Silicon/Qemu/SbsaQemu/Include/Library/HardwareInfoLib.h
> index 46fdad45353c..3e451ee344c7 100644
> --- a/Silicon/Qemu/SbsaQemu/Include/Library/HardwareInfoLib.h
> +++ b/Silicon/Qemu/SbsaQemu/Include/Library/HardwareInfoLib.h
> @@ -15,6 +15,19 @@ typedef struct{
>     UINT64  AddressSize;
>   } MemoryInfo;
>   
> +/**
> +  Sockets: the number of sockets on sbsa-ref platform.
> +  Clusters: the number of clusters in one socket.
> +  Cores: the number of cores in one cluster.
> +  Threads: the number of threads in one core.
> +**/
> +typedef struct{
> +  UINT32 Sockets;
> +  UINT32 Clusters;
> +  UINT32 Cores;
> +  UINT32 Threads;
> +} CpuTopology;
> +
>   /**
>     Get CPU count from information passed by Qemu.
>   
> @@ -83,4 +96,17 @@ GetNumaNodeCount (
>     VOID
>     );
>   
> +/**
> +  Get cpu topology(sockets, clusters, cores, threads) from device tree passed by Qemu.
> +
> +  @param [out]  CpuTopo     A pointer to the cpu topology.
> +
> +
> +  @retval                   the information of cpu topology.
> +**/
> +VOID
> +GetCpuTopology (
> +  OUT CpuTopology *CpuTopo
> +  );
> +
>   #endif /* HARDWARE_INFO_LIB */
> diff --git a/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.c b/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.c
> index 4c22e7d6ee47..a12dc0244da5 100644
> --- a/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.c
> +++ b/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.c
> @@ -179,3 +179,36 @@ GetNumaNodeCount (
>   
>     return NumberNumaNodes;
>   }
> +
> +/**
> +  Get CPU topology.
> +**/
> +VOID
> +GetCpuTopology (
> +  OUT CpuTopology *CpuTopo
> +  )
> +{
> +  UINTN          SmcResult;
> +  UINTN          Arg0;
> +  UINTN          Arg1;
> +  UINTN          Arg2;
> +  UINT32         NumCores = GetCpuCount();
> +
> +  SmcResult = ArmCallSmc0(SIP_SVC_GET_CPU_TOPOLOGY, &Arg0, &Arg1, &Arg2);

Can you use ArmCallSmc() directly? TF-A returns 5 arguments for this SMC 
call, we use 4 and calculate 5th one. Once we improve SMCCC code in EDK2 
the 5th one would be used directly.

> +  if (SmcResult != SMC_SIP_CALL_SUCCESS) {
> +    DEBUG ((DEBUG_ERROR, "%a: SIP_SVC_GET_CPU_TOPOLOGY call failed. We have no cpu topology information.\n", __FUNCTION__));
> +    ResetShutdown ();
> +  } else {
> +    CpuTopo->Sockets = Arg0;
> +    CpuTopo->Clusters = Arg1;
> +    CpuTopo->Cores = Arg2;

> +    CpuTopo->Threads = NumCores / (CpuTopo->Sockets * CpuTopo->Clusters * CpuTopo->Cores);

Once SMCCC gets improved this would be read directly from TF-A.

> +  }
> +
> +  DEBUG(( DEBUG_INFO, "%a: CPU Topology: sockets are %d, clusters are %d, cores are %d, threads are %d\n",

Can you replace " are" with ":" ("sockets: %d, clusters: %d")? Those 
numbers can be singular.

> +      __FUNCTION__,
> +      CpuTopo->Sockets,
> +      CpuTopo->Clusters,
> +      CpuTopo->Cores,
> +      CpuTopo->Threads ));
> +}
> \ No newline at end of file



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