Increasing guest memory in Vancouver

[Markus Partheymueller]

Hi Norman,

experimenting with the link address of Vancouver, I encountered very
mixed results.
Using 0x6000000 works fine, whereas addresses like 0x47000000, 0x80000000,
0xa0000000 or 0xb0000000 cause pagefaults very early in the startup of Genode.
Init complains about addresses having changed after attach.

This leads me to my real question: How is the link address restricted, or how
does it affect the memory situation? Maybe you could just elaborate a
bit more on
how the entire memory handling works when using vancouver on Genode.

Maybe that could help me find out what is causing my current problems,
because I think it could me memory-related.

Cheers

Markus

On 19 July 2012 11:19, Norman Feske <norman.feske at ...1...> wrote:
> Hi Markus,
>
>> I used run/vancouver as starting script, yes. And I noticed that
>> increasing to something around 90 MiB works without problems. Going
>> beyond that (e.g., 100MiB) strange things happen like page faults
>> where there should not be ones, or for example an INT 3 debug
>> instruction which seems to "forget" about the parameter it was passed.
>
> I forgot to mention another point that needs to be considered: The link
> address of the Vancouver program.
>
> The lower portion of Vancouver's address space corresponds to the
> guest-physical memory. This one-to-one relationship is imposed by the
> NOVA hypervisor. For this reason, this particular virtual address range
> must be kept free from ordinary memory objects (as I outlined in my
> reply to Julian's posting). This includes dataspaces attached to
> Vancouver's address space but also Vancouver's text, data, and bss
> segments. If Vancouver used the default link address used by normal
> Genode programs, this invariant would be violated. Therefore, the link
> address is explicitly specified in Vancouver's target.mk file.
> Currently, it is set to 0x50000000, which might explain your problems.
> Can you try to increase this value?
>
> Cheers
> Norman
>
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