Re: [PATCH 27/27] KVM: PPC: Add Documentation about PV interface

On Fri, 2010-07-02 at 20:41 +0200, Alexander Graf wrote:

The u64s are 64-bit aligned, should they always be?

That's obvious, isn't it? And the ABI only specifies u64s to be 32 bit
aligned, no? At least that's what ld and std specify.

No, the PowerPC ABI specifies u64's to be 64-bit aligned, even for
32-bit binaries.

Ben.

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+The "ld" and "std" instructions are transormed to "lwz" and "stw"

instructions

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+respectively on 32 bit systems with an added offset of 4 to

accomodate for big

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+endianness.

Will this add never overflow?  Is there anything that checks for it?

It basically means that to access dar, we either do

ld  rX, DAR(0)

or

lwz rX, DAR+4(0)

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+mtmsrd      rX, 0           b       <special mtmsr section>
+mtmsr                       b       <special mtmsr section>

mtmsr rX

Nod.