From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@qumranet.com>
Subject: Re: [PATCH] kvm: bios: Put AP boot up code to 0x1000
Date: Sun, 10 Aug 2008 10:50:04 +0300
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References: <200807311043.20880.sheng.yang@intel.com> <200808010919.00663.sheng.yang@intel.com> <033901c8f4d6$5b972570$0201a8c0@zeug> <200808051614.33138.sheng.yang@intel.com> <02a901c8f80f$940da820$0201a8c0@zeug>
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Cc: "Yang, Sheng" <sheng.yang@intel.com>, kvm@vger.kernel.org
To: Sebastian Herbszt <herbszt@gmx.de>
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Sebastian Herbszt wrote:
>
> The AP enters HALT state with IF=0. What can make it resume at the
> following "jmp 1b"? NMI? SMI?
>

Yes, but also INIT.

We might ignore IF=0 for hlt (which would be a bug).

> I think i read something about a need for 4kb alignment for the
> startup vector in the mp specs. AP_BOOT_ADDR is currently
> at 0x10000 (16 x 4kb).
>

Yes, the SIPI address is 4K x sipi vector.

> - Sebastian
>
> --- rombios32start.S.orig Wed Aug  6 21:37:22 2008
> +++ rombios32start.S Wed Aug  6 21:39:17 2008
> @@ -40,6 +40,7 @@ _start:
>
>   .code16
> smp_ap_boot_code_start:
> +  cli
>   xor %ax, %ax
>   mov %ax, %ds
>   xor %eax, %eax
> @@ -60,6 +61,7 @@ smp_ap_boot_code_start:
> 12:
>
>   incw CPU_COUNT_ADDR
> +  ljmp $0xe000, $(1f-_start)
> 1:
>   hlt
>   jmp 1b
>

Looks good.  Please post with signoff and changelog.


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