Re: [patch 0/2] Handle multiple exceptions (fixes Win2003 reboot by triple fault)

[Avi Kivity <avi@redhat.com>]

On 11/12/2009 03:05 PM, Gleb Natapov wrote:
> On Thu, Nov 12, 2009 at 01:41:31PM +0100, Jan Kiszka wrote:
>    
>> Gleb Natapov wrote:
>>      
>>> On Wed, Nov 11, 2009 at 05:29:47PM -0200, Marcelo Tosatti wrote:
>>>        
>>>> I suppose a complete fix would be to follow the "Conditions for
>>>> Generating a Double Fault" with support for handling exceptions
>>>> serially.
>>>>
>>>> But this works for me.
>>>>
>>>>          
>>> I prefer proper solution. Like one attached (this is combination of ths
>>> patch by Eddie Dong and my fix):
>>>        
>> Nice, preferred here as well. I only have a minor comment below.
>>
>>      
> Move Double-Fault generation logic out of page fault
> exception generating function to cover more generic case.
>
> Signed-off-by: Eddie Dong<eddie.dong@intel.com>
> Signed-off-by: Gleb Natapov<gleb@redhat.com>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 76c8375..88c4490 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -248,12 +248,61 @@ void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data)
>   }
>   EXPORT_SYMBOL_GPL(kvm_set_apic_base);
>
> +#define EXCPT_BENIGN		0
> +#define EXCPT_CONTRIBUTORY	1
> +#define EXCPT_PF		2
> +
> +static int exception_class(int vector)
> +{
> +	if (vector == 14)
> +		return EXCPT_PF;
> +	else if (vector == DE_VECTOR || (vector>= TS_VECTOR&&  vector<= GP_VECTOR))
> +		return EXCPT_CONTRIBUTORY;
> +	else
> +		return EXCPT_BENIGN;
> +}
>    

It's actually less readable.  I know 11 is between 10 and 13, but is 
NP_VECTOR between TS_VECTOR and GP_VECTOR?

This is better as a switch, or even:

u8 exception_class[] = {
    [PF_VECTOR] EXPT_PF,

etc.


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