Messages in this thread | | | Date | Mon, 17 Dec 2012 17:03:50 +0000 | From | "Jan Beulich" <> | Subject | Re: [GIT PULL] x86/uapi for 3.8 |
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>>> On 17.12.12 at 17:39, "H. Peter Anvin" <hpa@linux.intel.com> 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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