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

[Gleb Natapov <gleb@redhat.com>]

On Thu, Mar 24, 2011 at 01:27:39PM +0100, Michal Suchanek wrote:
> On 23 March 2011 23:32, Jordan Justen <jljusten@gmail.com> wrote:
> > 2011/3/23 Gleb Natapov <gleb@redhat.com>:
> >> 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.
> 
My thoughts exactly. It is double blurry in virtualization world where
moving any media from VM to VM is so easy.

> 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

--
			Gleb.