Re: Any way to map physical address 0xe0000000?

[Alexandre Courbot]
> Well, unfortunately the address in question happens to be 0xe0000000
> on all the (virtual) machines I have tried, which is unfortunately
> reserved by Pistachio and appears to be strictly forbidden to
> access.  I have tried writing the area from Sigma0, and even that is
> caught by the L4 kernel with the following message :

> sigma0 accessed kernel space @ e0000000, ip=00020438 - deny

> I have tried disabling the check that triggered this message in the
> kernel, and after that I can successfully draw on the screen from
> Sigma0 (which confirms that the address is correct), but as could be
> expected the system becomes unusuable shortly afterwards. So now I'm
> kind of stuck. Any idea on what I could do here? For performance
> reasons, using the real-mode windowing functions is not an option...

Even though sigma0 cannot touch the memory in the upper part of the
address space, it can still map the memory to other address spaces.
Have some task use the sigma0 protocol to ask for the proper region of
physical memory and map it into some lower part of its address space
(see include/l4/sigma0.h).

	eSk