Re: [PATCH] tpr optimization: clear the vapic area on boot

[Avi Kivity <avi@redhat.com>]

On 11/16/2010 12:49 PM, Avi Kivity wrote:
> If the option rom is loaded with rep/insb (as newer seabios versions do), then
> the writes to the vapic area may be corrupted by the kernel.
>
> Fix by explicitly clearing the vapic area on option rom startup.
>
> Signed-off-by: Avi Kivity<avi@redhat.com>
> ---
>   pc-bios/bios.bin          |  Bin 131072 ->  131072 bytes

This bit was unintended.

> diff --git a/pc-bios/optionrom/vapic.S b/pc-bios/optionrom/vapic.S
> index afe98a9..3c8dcf1 100644
> --- a/pc-bios/optionrom/vapic.S
> +++ b/pc-bios/optionrom/vapic.S
> @@ -4,6 +4,17 @@
>   _start:
>   	.short 0xaa55
>   	.byte (_end - _start) / 512
> +	# clear vapic area: firmware load using rep insb may cause
> +	# stale tpr/isr/irr data to corrupt the vapic area.
> +	push %es
> +	push %cs
> +	pop %es
> +	xor %ax, %ax
> +	mov $vapic_size/2, %cx
> +	lea vapic, %di
> +	cld
> +	rep stosw
> +	pop %es
>   	mov $vapic_base, %ax
>   	out %ax, $0x7e
>   	lret

This is the interesting part.

-- 
error compiling committee.c: too many arguments to function