Yes. ACPI1.0 below 4G limitation is defined in ACPI spec, clearly. OVMF X64 PEI has 4G limitation is OVMF implementation choice. Other platform *may* choose 2G, or 8G, or 0~1G+4G+5G. I hope PI specification can give us some guidance on how to handle that.
Thanks to raise this and we will discuss this in PIWG meeting for suggestion. Thank you Yao Jiewen From: edk2-devel [mailto:[email protected]] On Behalf Of Laszlo Ersek Sent: Wednesday, February 24, 2016 1:04 AM To: Ard Biesheuvel Cc: Ni, Ruiyu; Tian, Feng; [email protected]; Justen, Jordan L; [email protected]; [email protected]; Yao, Jiewen; Gao, Liming; Fan, Jeff; Zeng, Star Subject: Re: [edk2] [PATCH v3 2/4] IntelFrameworkModulePkg: BdsDxe: only allocate below 4 GB if needed On 02/23/16 17:47, Ard Biesheuvel wrote: > On 23 February 2016 at 17:06, Laszlo Ersek wrote: > [supersnip] >> By that I don't mean *another* new PCD, beyond the ACPI version PCD >> that Ard's patch series already contains -- I mean a more generic PCD >> that >> *replaces* the ACPI version PCD, and controls the allocations across >> all drivers. >> > > I disagree here. Whether you want only ACPI 5.0 and later tables, and > whether you need your allocations to be below 4 GB to be shareable > with PEI are completely orthogonal, imo. > > In fact, I am going to respin the AcpiTableDxe to keep the FACS table > below 4 GB for now, and we can wire it up to whichever solution we > come with up when we do, because I don't see this discussion coming to > a close in the near future. On top of that, FACS is not even used on > arm64 as far as I can figure out. > > Note that I still think this is a valuable discussion to have, but > allocating below 4 GB because ACPI tables only carry 32-bit address > fields or allocating below 4 GB because of some internal PI limitation > are completely different things, and should not be confused. Fair enough. So let's see if we can find a way (another new PCD, or another mechanism) that can constrain the allocations in question below 4GB. Thanks Laszlo _______________________________________________ edk2-devel mailing list [email protected]<mailto:[email protected]> https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
