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Re: [Xen-devel] [PATCH v3 for-4.5 0/9] xen: arm: support for > 40-bit physical addressing

On Mon, Sep 22, 2014 at 2:21 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> On Fri, 2014-09-19 at 20:16 +0530, Vijay Kilari wrote:
>> On Thu, Sep 18, 2014 at 5:39 AM, Ian Campbell <ian.campbell@xxxxxxxxxx> 
>> wrote:
>> > ARM64 systems can support up to 48-bits of physical address, but
>> > currently we configure both Stage-1 and Stage-2 for only 40-bits.
>> > However there are systems with peripherals mapped higher up, in order to
>> > support those we need to support 48-bits as output for stage-1 as well
>> > as input and output for stage-2. Stage-2 support is needed in order to
>> > map them 1:1 to dom0.
>> >
>> > Unfortunately as the last commit message explains in a bit more detail
>> > supporting larger input sizes on the p2m is a pain because it means we
>> > can no longer statically decide to use a 3-level p2m with 2 concatenated
>> > pages at the root and need to be able to support either that *or* a
>> > 4-level p2m with no root concatenation. There is simply no static choice
>> > which supports both 40- and 48-bits of IPA.
>> >
>> > So this series goes through the various functions which manipulate or
>> > walk page tables and makes them able to support a dynamic starting level
>> > and concatenation before switching arm64 to make the choice dependent on
>> > the h/w capabilities.
>> >
>> > This is somewhat loosely based on Vijay's original "Add 4-level page
>> > table for stage 2 translation" series but due to the need to switch to
>> > dynamic p2m levels not much of that remains.
>> >
>> > I haven't actually been able to track down a system with >42-bit PASize.
>> > Vijay, I'm hoping you can test this new version of the series on such a
>> > system/model (thanks for your feed back on the previous iteration).
>> Can you please share your code base for testing it?. I could not
>> find any branch here
>> http://xenbits.xen.org/gitweb/?p=people/ianc/xen.git;a=summary
> Done, see the 48bit-addresses-v3 branch of that repo.

Tested OK. Was able to boot with 48 bit PA

(XEN) P2M: 48-bit IPA with 48-bit PA
(XEN) P2M: 4 levels with order-0 root, VTCR 0x80053590

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