Re: [PATCH 1/1] UefiCpuPkg/MpInitLib: fix apic mode for cpu hotplug

["Gerd Hoffmann" <kraxel@redhat.com>]

On Tue, Mar 07, 2023 at 01:20:37PM +0100, Gerd Hoffmann wrote:
> In case the number of CPUs can in increase beyond 255
> due to CPU hotplug choose x2apic mode.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

Ping.  Any comments on this patch?

thanks,
  Gerd

> ---
>  UefiCpuPkg/Library/MpInitLib/MpLib.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> index e5dc852ed95f..d73b95001263 100644
> --- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
> +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> @@ -526,7 +526,9 @@ CollectProcessorCount (
>    //
>    // Enable x2APIC mode if
>    //  1. Number of CPU is greater than 255; or
> -  //  2. There are any logical processors reporting an Initial APIC ID of 255 or greater.
> +  //  2. The platform exposed the exact *boot* CPU count to us in advance, and
> +  //     more than 255 logical processors are possible later, with hotplug; or
> +  //  3. There are any logical processors reporting an Initial APIC ID of 255 or greater.
>    //
>    X2Apic = FALSE;
>    if (CpuMpData->CpuCount > 255) {
> @@ -534,6 +536,10 @@ CollectProcessorCount (
>      // If there are more than 255 processor found, force to enable X2APIC
>      //
>      X2Apic = TRUE;
> +  } else if ((PcdGet32 (PcdCpuBootLogicalProcessorNumber) > 0) &&
> +             (PcdGet32 (PcdCpuMaxLogicalProcessorNumber) > 255))
> +  {
> +    X2Apic = TRUE;
>    } else {
>      CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
>      for (Index = 0; Index < CpuMpData->CpuCount; Index++) {
> -- 
> 2.39.2
> 

--