Re: [PATCH] Handle #SS(0), caused by address size override in vm86 mode

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Kamble, Nitin A wrote:
> Hi Avi,
>
> I was playing with KVM while booting SuSE Linux 10.1 on it. And I 
> found it was bailing out with #SS fault. I root caused it to the 
> address size override opcode (0x67) from a mov instruction from the 
> boot loader.
>   The attached patch handles the #SS(0) fault with emulation, letting 
> guest can proceed further.

Applied, thanks.  Please use Linux style comment next time (
/*
 * blah blah
 */
)

> commit e7ae040a34ae99ac4eb08701b1a54a7e4315238a
> Author: Nitin A Kamble <nitin.a.kamble-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Date:   Wed May 16 21:05:58 2007 -0700
>
>      Instruction with address size override prefix opcode 0x67
>      Cause the #SS fault with 0 error code in VM86 mode.
>      <Signed-Off-By: Nitin A Kamble <nitin.a.kamble-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>
> diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
> index b1430e1..7d7edb7 100644
> --- a/drivers/kvm/vmx.c
> +++ b/drivers/kvm/vmx.c
> @@ -1487,7 +1487,9 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu,
>  	if (!vcpu->rmode.active)
>  		return 0;
>  
> -	if (vec == GP_VECTOR && err_code == 0)
> +    /* Instruction with address size override prefix opcode 0x67
> +       Cause the #SS fault with 0 error code in VM86 mode.  */
> +	if (((vec == GP_VECTOR) || (vec == SS_VECTOR)) && err_code == 0)
>  		if (emulate_instruction(vcpu, NULL, 0, 0) == EMULATE_DONE)
>  			return 1;
>  	return 0;
>   


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


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