Re: [GIT PULL] x86/uapi for 3.8

[Jan Beulich]

>>> On 17.12.12 at 17:39, "H. Peter Anvin" <hpa@xxxxxxxxxxxxxxx> wrote:
> Right, I think you nailed this one.  This patch copies PTEs from the
> kernel PTEs and thus they will have the global bit set.  It obviously
> makes no sense to *copy* PTEs from the kernel and yet leaving the global
> bit set, which means there are two ways of fixing it: either sharing
> page tables and use the cr4.pge off/on trick that Jan mentioned -- this
> would also be my preference -- and the other is to copy the PTEs but
> strip the global bit, which has the advantage that the actual kernel
> mappings will survive.

PTE copying is only one half of it. I think additionally L4 entries
get copied for the 1:1 mapping, and you can't strip the global
bits there without allocating separate page tables.

Jan

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