Re: [Qemu-devel] Re: POST failure (loop) with isapc and seabios

[Gleb Natapov]

On Thu, Nov 26, 2009 at 02:48:46AM -0500, Kevin O'Connor wrote:
> On Thu, Nov 26, 2009 at 09:20:34AM +0200, Gleb Natapov wrote:
> > On Thu, Nov 26, 2009 at 02:15:27AM -0500, Kevin O'Connor wrote:
> > > Now, if the bios is reloaded, the jump to the resume vector will skip
> > > ide, bios table, and other internal state setup.  So, later calls to
> > > the bios will likely fail.
> > > 
> > Seabios stores .bss and .data section in BIOS segments?
> 
> Yes.
> 
> >If this is the
> > case that you are right. Can we move them somewhere else and add it to
> > e820 map?
> 
> That would significantly complicate the code, and it wouldn't truly
> solve the issue as some data needs to be stored in the f-segment (eg,
> smbios anchor).
And I don't think support of switching to rm with triple fault worth
complication at all. BTW is seams QEMU doesn't event support 286 where
this is needed.

> 
> >Although event then switching to real mode using triple fault
> > after migration to newer BIOS will not work properly.
> 
> IMO, migrating to a new bios doesn't make sense - the bios is an
> application with state - one can't just replace the code.
> 
You don't migrate to a new BIOS. You migrate to a new QEMU that happens
to have a new BIOS. And ability to migrate to a newer QEMU is a must.

--
                        Gleb.