On 08/04/2010 11:36 AM, Avi Kivity wrote:
On 08/04/2010 07:30 PM, Avi Kivity wrote:
On 08/04/2010 04:52 PM, Anthony Liguori wrote:
This is not like DMA event if done in chunks and chunks can be pretty
big. The code that dials with copying may temporary unmap some pci
devices to have more space there.
That's a bit complicated because SeaBIOS is managing the PCI devices
whereas the kernel code is running as an option rom. I don't know
the BIOS PCI interfaces well so I don't know how doable this is.
Maybe we're just being too fancy here.
We could rewrite -kernel/-append/-initrd to just generate a floppy
image in RAM, and just boot from floppy.
How could this work? the RAM belongs to SeaBIOS immediately after
reset, it would just scribble over it. Or worse, not scribble on it
until some date in the future.
-kernel data has to find its way to memory after the bios gives
control to some optionrom. An alternative would be to embed
knowledge of -kernel in seabios, but I don't think it's a good one.
Oh, you meant host RAM, not guest RAM. Disregard.
This is basically my suggestion to libguestfs: instead of generating
an initrd, generate a bootable cdrom, and boot from that. The result
is faster and has a smaller memory footprint. Everyone wins.
Yeah, but we could also do that entirely in QEMU. If that's what we
suggest doing, there's no reason not to do it instead of the option rom
trickery that we do today.
The option rom stuff has a number of short comings. Because we hijack
int19, extboot doesn't get to run. That means that if you use -kernel
to load a grub (the Ubuntu guys for their own absurd reasons) then grub
does not see extboot backed disks. The solution for them is the same,
generate a proper disk and boot from that disk.
Regards,
Anthony Liguori
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
