Re: [PATCH 1/5] KVM: PPC: booke: Fix int_pending calculation for

[Scott Wood <scottwood@freescale.com>]

On 09/02/2011 02:25 PM, Alexander Graf wrote:
> 
> On 02.09.2011, at 20:17, Scott Wood wrote:
> 
>> On 09/02/2011 08:53 AM, Alexander Graf wrote:
>>> On 08/27/2011 01:31 AM, Scott Wood wrote:
>>>> int_pending was only being lowered if a bit in pending_exceptions
>>>> was cleared during exception delivery -- but for interrupts, we clear
>>>> it during IACK/TSR emulation.  This caused paravirt for enabling
>>>> MSR[EE] to be ineffective.
>>>
>>> But that means that int_pending can still be 1 even though there is none
>>> pending as we don't get the call to deliver_interrupts when it gets
>>> lowered. Please create a common function to remove a bit from
>>> pending_exceptions and do the check there.
>>
>> I can do that if you want, but kvmppc_core_deliver_interrupts() should
>> always get called before we return to the guest.  Dequeues that are
>> asynchronous to a guest exit should be very rare, and would be cured on
>> the first subsequent guest exit.
> 
> Yes, but this means we have yet another subtile indirect assumption. The more we have those, the more people who work on the code need to know about the code to actually work on it. So the easier we can keep the scheme, the better IMHO.
> 
> So yes, please replace clear_bit(pending, ...) with clear_bit_pending(...) or so which then would also do the required magic to set the shared page values.

OK.

-Scott