Re: [Xen-devel] Re: APIC rework

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

On 11/16/09 02:38, Zhang, Xiantao wrote:
> Hi, Keir/Jeremy
>    After you picking the two patches into upstream, we found it may break old 
> dom0 when assigned a level-triggered devices to a HVM domain.  The casue is 
> that, old dom0 can't provide trigger mode and polarity when they do 
> map_domain_pirq.  In attached patches, they introduce a bit to indicate 
> whether old dom0 or not.  
>
> xen-introduce-a-bit-to-identify-dom0-type.patch:  for hypervisor. 
> 0001-x86-Introduce-a-bit-MAP_COMPAT-mode-for-MAP_PIRQ_TY.patch: for pv ops 
> dom0. 
>   

Is there any way for the dom0 kernel to tell whether the hypervisor is
implementing the new ABI, so it can choose how to set up interrupts.

MAP_COMPAT_BIT doesn't seem like a very good name, because it implies
that setting it reverts to "compatible" behaviour.  I assume that
leaving it clear enables the historical behaviour and setting it enables
the new one (since old kernels won't be setting it).

    J
> Xiantao
>
>
> Keir Fraser wrote:
>   
>> On 13/11/2009 23:57, "Jeremy Fitzhardinge" <jeremy@xxxxxxxx> wrote:
>>
>>     
>>>> Sure, I'll check it in.
>>>>
>>>>         
>>> How would you feel about backporting this into a stable release?  If
>>> we start using this interrupt setup mechanism it will be a
>>> red-letter day for dom0/xen compatibility.
>>>       
>> There probably won't be another stable release until 4.0 now. There
>> will be a 3.4.3 about the same time though.
>>
>>  -- Keir
>>     
>   


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