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Re: [Qemu-devel] Why is SeaBIOS used with -kernel?
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] Why is SeaBIOS used with -kernel? |
Date: |
Mon, 21 Mar 2016 08:58:27 +0100 |
On Sa, 2016-03-19 at 20:31 +0000, Richard W.M. Jones wrote:
> I've been analyzing the libguestfs appliance[1] boot time. See
> attached file, especially the end of it.
>
> About 50% of the boot time is because of SeaBIOS.
And the bulk of that is loading the kernel from fw_cfg.
> I'm using the qemu -kernel option. I understand that the kernel needs
> some BIOS features, eg. video stuff, E820. But kvmtool comes with a
> really minimal BIOS that implements a tiny number of calls[2] and is
> far faster than SeaBIOS.
>
> Is there something I'm missing, or for Linux + -kernel could we use a
> much simpler BIOS?
marc (cc'ed) worked on porting the linuxboot option rom over to use the
new fwcfg dma interface, which should make things a order of magnitude
faster. That seems to be stalled though. Marc?
cheers,
Gerd