[Qemu-devel] Re: [PATCH][SEABIOS] Move qemu config port access functions into separate file.

[Gleb Natapov]

On Tue, Sep 15, 2009 at 10:02:59PM -0400, Kevin O'Connor wrote:
> On Tue, Sep 15, 2009 at 08:43:39AM +0300, Gleb Natapov wrote:
> > On Mon, Sep 14, 2009 at 08:08:24PM -0400, Kevin O'Connor wrote:
> > > As an aside, it would be good to have a conversation on general BIOS
> > > configuration options.  These types of settings are going to be useful
> > > on real hardware also - it would be nice to come up with a scheme that
> > > would work on qemu and coreboot.  Maybe something like
> > > get_config_u32("ShowBootMenu") - where on qemu it would get the info
> > > from the qemu port but on coreboot it would pull the setting from the
> > > coreboot flash filesystem.
> > > 
> > Lets have conversation now. Sounds useful to me. Do you want to use
> > strings as option names though? They add to BIOS image size and it is
> > limited, no?
> 
> My preference is strings - I think the long-term flexibility they
> provide is worth the slight additional overhead they require.
> 
> Currently, SeaBIOS is just under 64K -- if features continue to get
> added (eg, usb keyboard/boot) then it will likely creep into the
> e-segment.  I don't foresee any hard limits on space coming up.
> 
Fine by me.

The configuration interface should be able to read streams of data
though.  Qemu uses it to pass additional ACPI tables for instance. So
it not just simple key->value interface. get_config_u32("ShowBootMenu")
will work for simple cases but how can we express stream semantic? May be:

table_count = get_config_u16("AdditionalAcpiCount")
select_config("AdditionalAcpiTables");
for (i=0; i<table_count; i++) {
   len = config_read(table[i], table_len[i]);
}

--
                        Gleb.