On Mon, Nov 19, 2018 at 9:49 AM Gerd Hoffmann kraxel@redhat.com wrote:
Hi,
I'm investigating the SeaBIOS booting time, to understand if we can reduce the boot time in some cases (e.g. legacy hardware is not needed). I think this can be interesting also for NEMU developers.
The goal is to have only one image of SeaBIOS configurable at runtime to reduce the boot time, avoiding unnecessary initialization.
Why at runtime? What is bad with two images? With a runtime option you probably need some way to enable the "fastboot" hint for seabios, because some optimizations (like skipping ps/2 initialization) breaks functionality. So it must be opt-in so you can enable it if you know your use case is fine with that. But "qemu -boot fast=on" isn't much different from "qemu -bios seabios-fastboot.bin" after all ...
You are right, but maybe having a single image can be simpler to distribute, and we can implement something (eg. using fw_cfg) to selectively enable features needed. Anyway, as the first step, I'll try to build a separate image of SeaBIOS.
Any pointers or suggestions would be helpful.
seabios could try to skip initializing hardware without bootindex with "qemu -boot menu=off,strict=on".
mmconfig support? I think that would reduce the number of vmexits needed for pci initialization.
Thank you very much, I'll investigate that points.
Cheers, Stefano
cheers, Gerd