Re: [PATCH v2] MdeModulePkg/PeiCore: honour minimal runtime allocation granularity

["Zeng, Star" <star.zeng@intel.com>]

According to PI Spec.
"Note:MemoryBaseAddress and MemoryLength must each have 4-KiB granularity to meet the page size requirements of UEFI."

Memory allocation HOB covers full pages only.

Thanks,
Star

-----Original Message-----
From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org] 
Sent: Friday, March 3, 2017 5:12 PM
To: Gao, Liming <liming.gao@intel.com>
Cc: edk2-devel@lists.01.org; Zeng, Star <star.zeng@intel.com>
Subject: Re: [edk2] [PATCH v2] MdeModulePkg/PeiCore: honour minimal runtime allocation granularity

On 3 March 2017 at 09:05, Gao, Liming <liming.gao@intel.com> wrote:
> Ard:
>   First is to make FreeMemoryTop at the expected alignment. If original FreeMemoryTop is not aligned, it will be adjusted to be align. Then, there is one memory hole that can't be used any more. I suggest to create BuildMemoryAllocationHob() with EfiConventionalMemory to describe this hole.

OK. But the original code may already result in some non-page aligned memory to be discarded, should that be described as well? Or should the EfiConventionalMemory HOB cover full pages only?

Now, MdePkg\Library\PeiMemoryAllocationLib AllocateAlignedPages() uses this way to describe extra memory space.

Thanks,
Ard.