Re: [Qemu-devel] OVMF, SeaBIOS & non-CSM based legacy boot

[Michal Suchanek]

On 23 March 2011 23:32, Jordan Justen <address@hidden> wrote:
> 2011/3/23 Gleb Natapov <address@hidden>:
>> On Tue, Mar 22, 2011 at 02:53:16PM -0700, Jordan Justen wrote:
>>> To support a boot override for UEFI, this full path would be needed.
>>> For the purposes of a UEFI boot override, could the user could provide
>>> the partition & path info?
>>>
>> How the user knows what to provide. In most cases this user will be
>> management anyway. So the use case is like this: new HD is connected
>> to a VM and user wants to boot whatever is installed there.
>
> Yeah, that sounds like something something you or I might do, but not
> your average user.
>
> But, a VM user is most likely not your average user I guess. :)
>
>> With legacy
>> boot this is the matter of running MBR code, with UEFI user need to boot
>> something else and browse file system hierarchy to find magic file to
>> boot from?
>> Sound like step backward even from legacy bios :)
>
> True, it is not a great scenario.
>
> But you can set up the boot options by browsing the filesystems in the
> firmware setup program.
>
>> Is the some notion of default boot in UEFI.
>
> Only for removable media (CD, floppy, USB).  In that case
> /efi/boot/boot(ia32|x64).efi can be 'searched' for.
>

To the contrary.

The distinction between removable and fixed media is quite blurry these days.

Is an eSATA disk removable? Or a SATA disk connected to AHCI
controller through an internal (but hotplug capable) connector?
And when I unplug the disk, put it into an enclosure and connect
through USB has it magically started to be removable then?

When installing EFI bootloaders it is suggested to create a small FAT
partition at the start of the disk and put the loader there, just
under this name.

The Apple EFI also understands some variables stored in their HFS
volumes but that's another story.

If you want to prepare a disk image for somebody to use you *can* put
the bootloader in the well-known location.

If you pass just the raw disk image to somebody else it is technically
removable and should use the removable path, and the user can attach
it through the USB emulation if they insist on making it clearly
removable.

Thanks

Michal