On Thu, Aug 13, 2015 at 5:48 AM, Adrian Danis <[email protected]>
wrote:

> Currently there is no support in seL4 for taking advantage of hardware
> support for detecting dirty/accessed pages. If you want this then you must
> emulate this in software by changing the access writes on pages and
> handling the resulting page faults.
>
> The reason for not supporting any underlying hardware features for this is
> the original, and verified, platform that seL4 was written, an armv6, did
> not have hardware support for tracking this.
>
> Since porting seL4 to x86 and newer ARM architectures that have support
> for this there has not been any perceived need for this, so it has not been
> done. There is certainly no reason requesting such information could not be
> done within the capability model.
>

This is why I was asking if having mapping rights on the page
descriptor/page table would be sufficient.  If you can change which
physical page a virtual address refers to, you could probably also have
enough privilege to be trusted with dirty/accessed bit.

Is this the sort of "within the capability model" you are referring to?
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