Re: [Xen-devel] How EPT translates an X86_32 guest physical address?

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2010-11-17 at 10:32 +0000, George Dunlap wrote:
> The exact implementation of 32-bit mode on a 64-bit capable processor
> is something only the engineers at Intel know; but logically yes,
> whatever it does is equivalent to first zero-extending the 32-bit
> value.

Even on x86_32 physical addresses are >32 bit (think PAE). cr3 is a
physical address, even if the register which exposes it happens to be
limited to 32 bits. cr3 has probably already been expanded to a full
physical address by the time EPT sees it and I don't think there's any
difference between 32 and 64 bit (at least in this aspect) in how EPT
handles the translation from physical address to machine address.

Ian.


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