[coyotos-dev] i386 PTE question...

[Jonathan S. Shapiro]

On Tue, 2008-01-15 at 15:06 -0500, Jeroen C. Visser wrote:
> > The WK bit being stored in a software-defined bit is an extension of the
> > same issue. If we traverse the hardware table, we need to know whether
> > the fetched capability must be weakened before returning it.
> 
> Then is it correct to state that the WK bit is applicable only to cap pages?
> In other words, is the WK bit only examined when the PTE points to a cap
> page and a cap is being read from/written to it?


I'm not sure. It may be that the WK bit can appear in page directory
PDEs as well, in the same way that write permission can be disabled at
either level. Given the construction algorithm, this is actually likely.

However, I believe that the following invariant should hold: wherever
the WK bit is set, writes should be disabled.

shap