[Xen-devel] Re: [PATCH] Handle MSI irq storm

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

I thought that there already was storm-avoidance logic included, because of
the other storm scenario you used to be able to reproduce? Also this patch
looks like it will only avoid storms destined for an HVM guest. A non-HVM
irq will have IRQ_INPROGRESS cleared before interrupt delivery is
re-enabled. So if a storm does occur, it will look like the previous
interrupt was already handled when it in fact wasn't?

In the hvm EOI function you clear IRQ_INPROGRESS but do not ->enable() the
irq line. Is that correct?

 -- Keir

On 3/7/08 06:15, "Shan, Haitao" <haitao.shan@xxxxxxxxx> wrote:

>  <<handle_msi_irq_storm.patch>> Hi, Keir,
> 
> This patch handles MSI irq storm. Unluckily, I have observed this
> phenomenon again. This will happen when some kind of MSI-X capable NIC
> is assigned to an HVM guest. The basic idea is to mask the interrupt on
> receiving the second interrupt and set a timer to unmask after 1ms.
> Can you have a look and give some comments on that? Thanks!
> 
> Best Regards
> Shan Haitao 



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