Re: [Qemu-devel] [PATCH 2/2] fw_cfg: Add blit operation for copying kernel, initrd, ..

[Aurelien Jarno]

On Sat, Jul 17, 2010 at 02:41:04PM +0100, Richard W.M. Jones wrote:
> 
> -- 
> Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
> virt-top is 'top' for virtual machines.  Tiny program with many
> powerful monitoring features, net stats, disk stats, logging, etc.
> http://et.redhat.com/~rjones/virt-top

> >From cd167170239d60c8d13c56c881ee5f31387857af Mon Sep 17 00:00:00 2001
> From: Richard Jones <address@hidden>
> Date: Sat, 17 Jul 2010 14:30:46 +0100
> Subject: [PATCH 2/2] fw_cfg: Add blit operation for copying kernel, initrd, 
> setup, cmdline.
> 
> This adds a "blit" operation for rapidly copying the kernel, initrd
> etc into the guest.  Instead of doing an "inb" operation for every
> byte of these images, the guest sets up a blit address and issues
> a special read_fw with the FW_CFG_BLIT bit set.  This instructs
> qemu to copy the whole of the image to the blit address.
> 
> With this patch, loading large initrds is several seconds faster,
> and overall boot time is reduced correspondingly.
> 
> Signed-off-by: Richard W.M. Jones <address@hidden>
> ---
>  hw/fw_cfg.c                   |   19 ++++++++++++++++++-
>  hw/fw_cfg.h                   |    7 +++++--
>  pc-bios/optionrom/linuxboot.S |    8 ++++----
>  pc-bios/optionrom/optionrom.h |   37 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 64 insertions(+), 7 deletions(-)

OpenBIOS also uses the same firmware interface, so it would need to be
changed if this patch is accepted.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
address@hidden                 http://www.aurel32.net