Re: [edk2-devel] question about PrmPkg

["Michael Kubacki" <mikuback@linux.microsoft.com>]

On 11/19/2023 9:09 PM, Yoshinoya wrote:
> Hi, Michael:
> Got it.
> 
> It seems linux kernel has introduced PRMT support default.
> And ARM vendors usually use this PRMT mechnism.
> 
> So how aout x86 platform?
> Does Win11 have supported PRMT on any X86 platform?
> 
Yes, support is available in Windows 11 and Windows Server 2022.

I requested open source Windows driver sample code to be made available 
here https://github.com/microsoft/Windows-driver-samples/issues/921.

> 
> best wishes,
> 
> 
> 
> 
> 
> At 2023-11-18 00:04:26, "Michael Kubacki" <mikuback@linux.microsoft.com> wrote:
>>On 11/17/2023 3:42 AM, Laszlo Ersek wrote:
>>> On 11/17/23 03:15, Yoshinoya wrote:
>>>> Hi,
>>>> I find there is a PrmPkg in udk source code.
>>>> Based on its Readme.md, its goal is to offload smm code to sci os
>>>> mechanisms.
>>>>
>>>> So, is there any actual use case on real platform now?
>>>>
>>>> It seems it's just a conceptional prototype.
>>> 
>>> It's way too big for it to be unused.
>>> 
>>> The original BZ was <https://bugzilla.tianocore.org/show_bug.cgi?id=3812>.
>>> 
>>> I'm sure Microsoft uses it in production. Client code for this
>>> infrastructure may be present in Project Mu (I didn't try to check), or
>>> in proprietary repositories. Perhaps Michael (CC'd) can share some details.
>>> 
>>I can't speak to how it is being used everywhere but it is used in 
>>production. Other vendors have been involved (at least at various points 
>>in time).
>>
>>The ACPI 6.4 spec reserved the PRMT table signature. The ACPI 6.5 spec 
>>defined the _SB._OSC bit for an OS to declare PRM compatibility and 
>>define a PRM OpRegion identifier. Support has been in iasl since 20200528.
>>
>>The PRM spec is on uefi.org. I believe this was ultimately pushed there 
>>by Intel.
>>
>>https://uefi.org/sites/default/files/resources/Platform%20Runtime%20Mechanism%20-%20with%20legal%20notice.pdf
>>
>>It was added to edk2 to provide code for specifications on uefi.org, 
>>make it available to vendors that do not use Mu but use it, and 
>>similarly, in response to interest from others.
>>
>>The Code in PrmPkg is infrastructure to support loading custom handlers 
>>so it is not expected to receive a large amount of churn.
>>
>>> Laszlo
>>> 
>>> 
>>> 
>>> 
>>> 
>>
>>
>>
>>
> 
> 


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