[RFC PATCH 0/2] arm64: Add support for 48-bit Physical Addresses

Marc Zyngier marc.zyngier at arm.com
Wed Nov 27 06:04:05 EST 2013


[CC-ing the maintainers - seems odd they were not cc-ed the first place]

On 27/11/13 07:34, mohun106 at gmail.com wrote:
> From: Radha Mohan Chintakuntla <rchintakuntla at cavium.com>
> 
> This patch series provides an implementation of supporting 48-bit
> Physical Addresses for ARMv8 platforms. It is the maximum width that
> any ARMv8 based processor can support. 
> 
> The implementation extends the existing support of 40-bit PA.The kernel
> and user space will now be able to access 128TB each. With 4KB page size
> the Linux now will be using 4 levels of page tables by making use of
> 'pud'. And with 64KB page size the Linux will be using 3 levels of page
> tables.
> 
> The code has been tested with LTP.

Aside from finding out whether or not this is a useful change, this
breaks KVM, more specifically the way kernel pages are mapped into HYP.
Also, guests will still be limited to 40-bit IPAs, and the stage-2
output range needs to be addressed as well.

	M.
-- 
Jazz is not dead. It just smells funny...




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