ArmPkg: TranslationTable exceeding TempRam on virtual systems

ArmPkg: TranslationTable exceeding TempRam on virtual systems

[Bret Barkelew]

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I’m fielding a series of questions coming out of our compatriot team that deals with virtual FW (for HyperV). They’re seeing ARM64 systems that have lots of RAM vastly exceeding the TempRam that’s passed into the system due to HOB allocations to create all the 4k entries for the early page tables.

Is this a known limitation or are we doing something dumb?
Is there a way to sparsely populate the page tables and fill them in more in DXE?
I’ve seen some questions about 64k pages on the list before. Is that an option?

Thanks in advance!

- Bret


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Re: ArmPkg: TranslationTable exceeding TempRam on virtual systems

[Arti Gupta]

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Hey everyone,
Wondering if there are more thoughts on the questions Bret has posted below?
Thanks,
Arti

From: Bret Barkelew <Bret.Barkelew@microsoft.com>
Sent: Thursday, May 27, 2021 4:29 PM
To: devel@edk2.groups.io; Arti Gupta <argu@microsoft.com>
Subject: ArmPkg: TranslationTable exceeding TempRam on virtual systems

I'm fielding a series of questions coming out of our compatriot team that deals with virtual FW (for HyperV). They're seeing ARM64 systems that have lots of RAM vastly exceeding the TempRam that's passed into the system due to HOB allocations to create all the 4k entries for the early page tables.

Is this a known limitation or are we doing something dumb?
Is there a way to sparsely populate the page tables and fill them in more in DXE?
I've seen some questions about 64k pages on the list before. Is that an option?

Thanks in advance!

- Bret


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Re: ArmPkg: TranslationTable exceeding TempRam on virtual systems

[Arti Gupta]

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Hi,
Hoping to find a solution here. Would someone mind helping me with this?
Thanks a lot,
Arti

From: Arti Gupta
Sent: Thursday, July 1, 2021 2:35 AM
To: Bret Barkelew <Bret.Barkelew@microsoft.com>; devel@edk2.groups.io
Subject: RE: ArmPkg: TranslationTable exceeding TempRam on virtual systems

Hey everyone,
Wondering if there are more thoughts on the questions Bret has posted below?
Thanks,
Arti

From: Bret Barkelew <Bret.Barkelew@microsoft.com<mailto:Bret.Barkelew@microsoft.com>>
Sent: Thursday, May 27, 2021 4:29 PM
To: devel@edk2.groups.io<mailto:devel@edk2.groups.io>; Arti Gupta <argu@microsoft.com<mailto:argu@microsoft.com>>
Subject: ArmPkg: TranslationTable exceeding TempRam on virtual systems

I'm fielding a series of questions coming out of our compatriot team that deals with virtual FW (for HyperV). They're seeing ARM64 systems that have lots of RAM vastly exceeding the TempRam that's passed into the system due to HOB allocations to create all the 4k entries for the early page tables.

Is this a known limitation or are we doing something dumb?
Is there a way to sparsely populate the page tables and fill them in more in DXE?
I've seen some questions about 64k pages on the list before. Is that an option?

Thanks in advance!

- Bret


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