Re: [PATCHv2 2 of 2] Move IOMMU faults handling into softirq for AMD-Vi.

[Wei Wang <wei.wang2@amd.com>]

On 01/18/2012 09:53 AM, Dario Faggioli wrote:
> On Tue, 2012-01-17 at 11:17 +0000, Keir Fraser wrote:
>>> Dealing with interrupts from AMD-Vi IOMMU(s) is deferred to a softirq-tasklet,
>>> raised by the actual IRQ handler. To avoid more interrupts being generated
>>> (because of further faults), they must be masked in the IOMMU within the low
>>> level IRQ handler and enabled back in the tasklet body. Notice that this may
>>> cause the log to overflow, but none of the existing entry will be overwritten.
>>>
>>> Signed-off-by: Dario Faggioli<dario.faggioli@citrix.com>
>>
>> This patch needs fixing to apply to xen-unstable tip. Please do that and
>> resubmit.
>>
> I see. I can easily rebase the patch but there are functional changes
> involved, so I'd like to know what you think it's best to do first.
>
> In particular, the clash is against Wei's patches introducing PPR. So
> now the IOMMU interrupt handler checks both event log and ppr log.
>
> Question is, should I move _BOTH_ these checks into softirq or just
> defer event log processing, and leave ppr log handling in hard-irq
> context? Quickly looking at the new specs, it seems to me that deferring
> both should be fine, but I'd really appreciate your thoughts...

I think put both event log and ppr log into softirq is fine. If you 
could have a patch like this, I can do a quick test on my machine.
Thanks,
Wei

> Wei, Jan, Tim?
>
> Thanks and regards,
> Dario
>