[Qemu-devel] Re: phys_page_find bug?

[Artyom Tarasenko <atar4qemu@gmail.com>]

On Fri, May 7, 2010 at 6:26 PM, Artyom Tarasenko
<atar4qemu@googlemail.com> wrote:
> phys_page_find (exec.c) returns sometimes a page for addresses where
> nothing is connected.
>
> One example, done with qemu-system-sparc -M SS-20
>
> ok f13ffff0 2f spacec@ .
>
> // The address translates correctly, in cpu_physical_memory_rw
> // addr== 0xff13ffff0 (where nothing is connected)
> // but then phys_page_find returns a nonzero and produces
>
> Unassigned mem read access of 1 byte to 0000000ff15ffff0 from xxxxx
>
> (note the "5" in the line above where "3" is expected)
>
> I wonder if this is only true for non-wired addresses, or whether
> phys_page_find can also
> find wrong pages for the addresses where something is connected?
>
> Or is my assumption is wrong and phys_page_find can return a page for
> not-connected
> addresses and the bug is actually in cpu_physical_memory_rw ?
>
> Is the qemu algorithm of working with the physical address space
> described somewhere?

I tried to switch devices off and found that the bug is triggered by
registering escc.
It's harder to debug without escc, so I can't tell whether something
else is causing
the problem too.

Is escc addressing somehow special?

>Is the qemu algorithm of working with the physical address space described somewhere?

I guess no one knows it anymore, since no-one cared to answer within a
half year :-/.

-- 
Regards,
Artyom Tarasenko

solaris/sparc under qemu blog: http://tyom.blogspot.com/