On 11/17/23 09:07, Dhaval Sharma wrote:
> Hi,
> I wanted to revisit this thread and I am maintaining the context as
> there are a lot of details already mentioned here regarding EFI_MEMORY_SP.
> Other than what has been addressed here, we also would like to have an
> option in edk2 to *avoid* using this type of memory for its own
> purposes. This seems like one of the motivations for original request
> and is being honored by OS today but not edk2 as it does not have any
> specific implementation today which takes this attribute into consideration.
> I would like to add PCD based implementation which informs edk2 NOT to
> use this memory for its own purposes and leave it alone (as still
> available memory to OS).
>
> Specific-purpose memory (SPM). The memory is earmarked for
> specific purposes such as for specific device drivers or applications.
> The SPM attribute serves as a hint to the OS to avoid allocating this
> memory for core OS data or code that can not be relocated.
> Prolonged use of this memory for purposes other than the intended
> purpose may result in suboptimal platform performance.
>
> Some more context:
> https://lwn.net/Articles/784971/

Why was EFI_MEMORY_SP introduced as a memory attribute, rather than its
own memory type?

Laszlo