Re: [Xen-devel] Page fault on mapped pages with reserved bits set

[Trammell Hudson <hudson@xxxxxxxxxxxxxx>]

On Wed, Jun 20, 2007 at 11:10:14PM +0100, Keir Fraser wrote:
> It's a protection violation on a write, because none of your page directory
> entries have bit 1 (_PAGE_RW) set. That bit gets ANDed down the entire page
> walk, so it needs to be set at every level for the page to actually be
> writable.

Super!  That was it.

The kernel was originally written for a CPU and system that allowed
the ring 0 code to write to memory, even if it was flagged as
non-writable.  Moving it into ring 3 has been problematic in other
areas, too, so it isn't booting all the way yet, but is making much
quicker progress now!

-- Trammell

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