[SerialICE] r87 - trunk/qemu-0.11.0

[joe at settoplinux.org]

On December 5, 2009 at 11:31 PM Stefan Reinauer <stepan at coresystems.de> wrote:

> joe at settoplinux.org wrote:
> > What does Qemu do when 0xcf9 is sent to bios Stefan?
> >
> >   
> 
> Hi Joe,
> 
> The I/O 0xcf9 is the "reset register" on most x86 systems. Writing
> certain values to it will cause a hard or soft reset.
> Qemu however does not emulate this behavior - as far as I can tell - it
> certainly does not while SerialICE is active, because all IO accesses go
> to the target (or are caught by LUA)
> 
> Basically what's missing in the LUA script to make resets via cf9 work
> properly is adding the following to SerialICE_IO_write_filter:
> 
>     if port == 0xcf9 and data == 0x06 then
>         SerialICE_system_reset()
>         return false, data
>    end
> 
> The serial communication code has been rewritten for the last release to
> be quite hick-up safe.. This means Qemu does not get out of sync if the
> target reboots, so all that needs to happen after a reboot of the target
> is to reboot the VM on the host, too, to let it start at the reset
> vector again... Otherwise it'll just try to execute code right after the
> out to cf9.. which is usually an endless loop as a safe guard.
> 
Yeh I know what 0xcf9 is, I just was not sure what Qemu did with it.
Sweet! Great work Stefan! I will have to get my head out of my ass and try it
out :-)

Thanks,
Joseph Smith
Set-Top-Linux
www.settoplinux.org