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

[Blue Swirl <blauwirbel@gmail.com>]

On Wed, Sep 30, 2009 at 9:35 AM, Gleb Natapov <gleb@redhat.com> wrote:
> On Tue, Sep 29, 2009 at 09:09:46PM -0400, Kevin O'Connor wrote:
>> On Sat, Sep 19, 2009 at 08:56:55PM +0300, Gleb Natapov wrote:
>> > On Sat, Sep 19, 2009 at 11:16:41AM -0400, Kevin O'Connor wrote:
>> > > Maybe a stream could be introduced with something like:
>> > > <name><len><data> <name2><len2><data2> ...
>> > >
>> > The format is already set. The are two ports. You write option id in
>> > first port and you read option value from second one. The value format
>> > is different for each option. Additional acpi table format is like I
>> > described above. If we want to use the same APIs for config access for
>> > coreboot and qemu the API will have to be general enough to accommodate
>> > both approaches. Changing formats is not an option at this stage.
>>
>> Okay - it doesn't sound like there is much overlap here between qemu
>> and coreboot.  On coreboot cbfs is used for pulling out option roms,
>> executables, and floppy images - none of which have much use under
>> qemu anyway.
>>
>> So, maybe we should just go back to the discussion of a config
>> interface.  I think it would be nice to have one api for getting
>> config items for both qemu and coreboot - something like
>> get_config_u32("ShowBootMenu").  On coreboot that info could then be
>> extracted from cbfs and qemu can get in from the "cfg port".
>>
>> Does that make sense?
>>
> Yes. That is the direction I was going to take. Lest implement simple
> name/value interface first and table loading code will be different.
> If there will be much overlap in table loading code we will unify it
> later.

The name/value interface could be useful for OpenBIOS too if we want
to avoid using NVRAM for OpenBIOS variables for compatibility. There
should be methods to iterate through all keys and get the byte size of
the value.

For example, current fw_cfg interface could be extended to allow
string keys in addition to integer keys.