Re: [Qemu-devel] [PATCH 0/2] extboot reloaded.

[Gerd Hoffmann <kraxel@redhat.com>]

On 11/17/09 12:36, Paul Brook wrote:
>>>> It would require a mechanism to do enumeration and identification
>>>> though.
>>>
>>> Huh?  Do you want export *all* block devices via extboot?  Will IDE
>>> drives show up twice then?
>>
>> No, because SeaBIOS already has an ATA driver so we wouldn't want to
>> expose IDE on the extboot bus.
>
> "SeaBIOS already has an ATA driver" doesn't seem a convincing argument for
> making IDE special, because I expect the BIOS will grow support for other
> block devices.

One of the reasons why I'd enable it only on explicit user request, so 
it can be used (temporarily) for cases where the bios has no native support.

> Either expose ever block device qemu knows about, or have extboot as a regular
> block device with no special handling. I strongly prefer the latter option.

Me too.

> In fact I'd much prefer to see extboot rewritten to just virtio-block.

Hmm, I'd prefer something which is *not* used by the guest OS, so it is 
a pure bootloader thing.  When using it to boot from scsi you don't want 
to have the disk show up twice (as virtio and scsi) in the guest.

Some non-pci virtio proxy could do the trick though, i.e. have 
virtio-blk-pci and virtio-blk-boot.  Would probably also simplify things 
on the seabios side as native virtio support code could be reused then.

cheers,
   Gerd