[SeaBIOS] [Qemu-devel] SeaBIOS booting time optimization

Gerd Hoffmann kraxel at redhat.com
Tue Nov 20 12:22:03 CET 2018


> > Background:  The drivers in seabios work on both virtual and physical
> > hardware (you can run seabios as coreboot payload on physical hardware).
> > There are quite a few places where are delays and timeouts which are
> > required to work properly on physical hardware.  But typically virtual
> > hardware is alot faster.  There is -- for example -- no time needed to
> > establish a sata link.  Link detection in ahci is instant on qemu.
> I'll investigate also other timeouts.

I'd focus on legacy lpc/isa hardware here.  PCI-ish hardware which has
such timeouts (sata, usb, ...) typically isn't present in the virtual
machine if you care about performance.  Or, in other words, the best way
to handle the sata link detection delay is to use "qemu -M q35,sata=off".


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