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Re: [Xen-devel] Question, How to share interrupt between Doms

On 02/10/2018 09:32, Peng Fan wrote:
Hi Julien, Stefano,

Hi Peng,

Do you have any suggestions on how to share one interrupt between Doms?

Sharing interrupts are usually a pain. You would need to forward the interrupts to all the domains using that interrupt and wait for them to EOI. This has security implications because you don't want DomA to prevent DomB receiving another interrupt because the previous one has not been EOIed correctly.

The issue is that a gpio controller has 32 in/out port, however it only has one 
binded interrupt. The interrupt handler needs to check the status bits to check 
which port has interrupt coming.
In my case, there are different devices using gpio interrupt that needs to be 
assigned to different doms.

From what you wrote, it looks like you expect the GPIO controller to be shared with multiple domains.

I don't think it is safe to do that. You need one domain (or Xen) to fully manage the controller. All the other domain will have to access either a virtual GPIO controller or PV one. In the former, interrupt would be virtual, while the latter the interrupt would be through even channel.

So sharing interrupt should not be necessary. Did I miss anything?


Julien Grall

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