Re: [Xen-devel] Question, How to share interrupt between Doms
On 08/10/2018 03:37, Peng Fan wrote: Hi Julien Hi Peng, -Original Message- From: Julien Grall [mailto:julien.gr...@arm.com] Sent: 2018年10月5日 1:27 To: Peng Fan ; Stefano Stabellini Cc: xen-devel@lists.xenproject.org; Andre Przywara Subject: Re: 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.gr...@arm.com] Sent: 2018年10月3日 0:03 To: Peng Fan ; Stefano Stabellini Cc: xen-devel@lists.xenproject.org; Andre Przywara 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 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? 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=. 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? Yes. What about the guests? Do they access directly the GPIO controller? Or did you introduce a PV protocol for this? Guest use PV to access GPIO in Dom0. When interrupt comes to dom0, the pv use event channel to forward the interrupt to Domu, I did not find a good way to do interrupt forwarding and let domu handle the interrupt as without Virtualization. Do you mean using a SPIs rather than an event channel to deliver the interrupt to the guest? I use generic_handle_irq() when frontent received the forwarded interrupt from dom0 in a eventchannel interrupt, but no work. Do you see any error? Would it be possible to paste logs? Another issue is in backend, request_threaded_irq for the gpio, some gpio will trigger interrupt before domu could handle the interrupt, this is because gpio default status or some on board devices pull up/down the gpio. I am not sure to understand the issue with that. It should not be different from the hardware case. Would it be possible to expand it? -- Julien Grall ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
Re: [Xen-devel] Question, How to share interrupt between Doms
Hi Julien > -Original Message- > From: Julien Grall [mailto:julien.gr...@arm.com] > Sent: 2018年10月5日 1:27 > To: Peng Fan ; Stefano Stabellini > Cc: xen-devel@lists.xenproject.org; Andre Przywara > > Subject: Re: 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.gr...@arm.com] > >> Sent: 2018年10月3日 0:03 > >> To: Peng Fan ; Stefano Stabellini > >> > >> Cc: xen-devel@lists.xenproject.org; Andre Przywara > >> > >> 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 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? > > > > 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>. 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? Yes. > > What about the guests? Do they access directly the GPIO controller? Or did you > introduce a PV protocol for this? Guest use PV to access GPIO in Dom0. When interrupt comes to dom0, the pv use event channel to forward the interrupt to Domu, I did not find a good way to do interrupt forwarding and let domu handle the interrupt as without Virtualization. I use generic_handle_irq() when frontent received the forwarded interrupt from dom0 in a eventchannel interrupt, but no work. Another issue is in backend, request_threaded_irq for the gpio, some gpio will trigger interrupt before domu could handle the interrupt, this is because gpio default status or some on board devices pull up/down the gpio. Thanks, Peng. > > Cheers, > > -- > Julien Grall ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
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.gr...@arm.com] Sent: 2018年10月3日 0:03 To: Peng Fan ; Stefano Stabellini Cc: xen-devel@lists.xenproject.org; Andre Przywara 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 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? 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=. 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@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
Re: [Xen-devel] Question, How to share interrupt between Doms
> -Original Message- > From: Julien Grall [mailto:julien.gr...@arm.com] > Sent: 2018年10月3日 0:03 > To: Peng Fan ; Stefano Stabellini > Cc: xen-devel@lists.xenproject.org; Andre Przywara > > 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 > > 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? 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=. But when dom0 notify remote, there is no hook in frontend driver and the other driver interrupt handler. Thanks, Peng. > > Cheers, > > -- > Julien Grall ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
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? Cheers, -- Julien Grall ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
[Xen-devel] Question, How to share interrupt between Doms
Hi Julien, Stefano, Do you have any suggestions on how to share one interrupt between Doms? 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. Thanks, Peng. ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
