Re: [V8 PATCH 7/8] pvh dom0: add check for pvh in vioapic_range

[George Dunlap <george.dunlap@eu.citrix.com>]

On 03/24/2014 09:34 AM, Jan Beulich wrote:
>>>> On 22.03.14 at 02:39, <mukesh.rathor@oracle.com> wrote:
>> --- a/xen/arch/x86/hvm/vioapic.c
>> +++ b/xen/arch/x86/hvm/vioapic.c
>> @@ -238,8 +238,13 @@ static int vioapic_write(
>>
>>   static int vioapic_range(struct vcpu *v, unsigned long addr)
>>   {
>> -    struct hvm_hw_vioapic *vioapic = domain_vioapic(v->domain);
>> +    struct hvm_hw_vioapic *vioapic;
>> +
>> +    /* pvh uses event channel callback */
>> +    if ( is_pvh_vcpu(v) )
>> +        return 0;
>>
>> +    vioapic = domain_vioapic(v->domain);
>
> I can see why the extra check is needed, but I can't see why you
> convert the initializer to an assignment: Afaict domain_vioapic() is
> safe even if d->arch.hvm_domain.vioapic == NULL.

Or better yet, just make it something like:

return vioapic && ((addr >= [...original range check]))

That way we don't have to have a PVH-specific hook at all.  If a domain 
doesn't have a vioapic for any reason, return 0.

  -George