[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Question, How to share interrupt between Doms
Hi Peng, On 04/10/2018 02:12, Peng Fan wrote: -----Original Message----- From: Julien Grall [mailto:julien.grall@xxxxxxx] Sent: 2018年10月3日 0:03 To: Peng Fan <peng.fan@xxxxxxx>; Stefano Stabellini <sstabellini@xxxxxxxxxx> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx; Andre Przywara <andre.przywara@xxxxxxx> Subject: Re: 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 onebinded 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 beassigned 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?When interrupts comes, the dom0 will handle that. Then forward the interrupt to domu. But I did not find a good method to forward the interrupt and hook the interrupt in domu dts and domu driver. In Domu, driver needs use request irq and the dts needs interrupt=<xx xx>. But when dom0 notify remote, there is no hook in frontend driver and the other driver interrupt handler. You say that Dom0 will receive the interrupt. So Dom0 is access directly the GPIO controller. Right? What about the guests? Do they access directly the GPIO controller? Or did you introduce a PV protocol for this? Cheers, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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