Re: [edk2-devel] [PATCH 0/4] Sync BSP's APIC mode to APs in MP init flow

["Ni, Ray" <ray.ni@intel.com>]

Gerd,
No. I don't plan to add PCD.
I thought that initially but in the end I figured out:
* PCD is a way to let platform configure the common logic behavior.
* Why not treat "X2 APIC status in BSP" as a "hardware" PCD?

With above thoughts, I prefer (a).
Platform can choose whether to define a "platform-level" PCD to control
platform behavior regarding whether to enable X2 APIC in BSP before CPU MP.

Comments?

Thanks,
Ray


> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Gerd
> Hoffmann
> Sent: Friday, July 7, 2023 4:56 PM
> To: devel@edk2.groups.io; Ni, Ray <ray.ni@intel.com>
> Subject: Re: [edk2-devel] [PATCH 0/4] Sync BSP's APIC mode to APs in MP init
> flow
> 
> On Fri, Jul 07, 2023 at 01:28:57PM +0800, Ni, Ray wrote:
> 
> [ empty cover letter ]
> 
> Summary of the patch series changes would be nice.
> 
> If I read things correctly this series will:
> 
>   (a) allow platforms use x2apic mode by simply switching the BSP into
>       x2apic mode early enough (for example in PlatformPei).
>   (b) avoids waking up all APs a second time to set apic mode.
> 
> Is that correct?
> 
> Do you still plan to add a PCD to enable x2apic mode, or is that plan
> obsoleted by (a) ?
> 
> take care,
>   Gerd
> 
> 
> 
> 
>