On 09/16/2014 10:51 PM, Alex Williamson wrote: > On Tue, 2014-09-16 at 00:01 +0200, Eric Auger wrote: >> On 09/12/2014 01:05 AM, Christoffer Dall wrote: >>> On Thu, Sep 11, 2014 at 04:51:14PM -0600, Alex Williamson wrote: >>>> On Thu, 2014-09-11 at 15:23 -0700, Christoffer Dall wrote: >>>>> On Thu, Sep 11, 2014 at 04:14:09PM -0600, Alex Williamson wrote: >>>>>> On Tue, 2014-09-09 at 08:31 +0100, Eric Auger wrote: >>>>>>> This RFC series aims at enabling KVM platform device passthrough. >>>>>>> It implements a VFIO platform device, derived from VFIO PCI device. >>>>>>> >>>>>>> The VFIO platform device uses the host VFIO platform driver which must >>>>>>> be bound to the assigned device prior to the QEMU system start. >>>>>>> >>>>>>> - the guest can directly access the device register space >>>>>>> - assigned device IRQs are transparently routed to the guest by >>>>>>> QEMU/KVM (3 methods currently are supported: user-level eventfd >>>>>>> handling, irqfd, forwarded IRQs) >>>>>>> - iommu is transparently programmed to prevent the device from >>>>>>> accessing physical pages outside of the guest address space >>>>>>> >>>>>>> This patch series is made of the following patch files: >>>>>>> >>>>>>> 1-7) Modifications to PCI code to prepare for VFIO platform device >>>>>>> 8) split of PCI specific code and generic code (move) >>>>>>> 9-11) creation of the VFIO calxeda xgmac platform device, without irqfd >>>>>>> support (MMIO direct access and IRQ assignment). >>>>>>> 12) fake injection test modality (to test multiple IRQ) >>>>>>> 13) addition of irqfd/virqfd support >>>>>>> 14-16) forwarded IRQ >>>>>>> >>>>>>> Dependency List: >>>>>>> >>>>>>> QEMU dependencies: >>>>>>> [1] [PATCH v2 0/9] Dynamic sysbus device allocation support, Alex Graf >>>>>>> http://lists.gnu.org/archive/html/qemu-ppc/2014-07/msg00047.html >>>>>>> [2] [RFC v3] machvirt dynamic sysbus device instantiation, Eric Auger >>>>>>> [3] [PATCH v2 0/2] actual checks of KVM_CAP_IRQFD and KVM_CAP_IRQFD_RESAMPLE, >>>>>>> Eric Auger >>>>>>> http://lists.nongnu.org/archive/html/qemu-devel/2014-09/msg00589.html >>>>>>> [4] [RFC] vfio: migration to trace points, Eric Auger >>>>>>> http://lists.nongnu.org/archive/html/qemu-devel/2014-09/msg00569.html >>>>>>> >>>>>>> Kernel Dependencies: >>>>>>> [5] [RFC Patch v6 0/20] VFIO support for platform devices, Antonios Motakis >>>>>>> https://www.mail-archive.com/kvm@xxxxxxxxxxxxxxx/msg103247.html >>>>>>> [6] [PATCH v3] ARM: KVM: add irqfd support, Eric Auger >>>>>>> https://lkml.org/lkml/2014/9/1/141 >>>>>>> [7] arm/arm64: KVM: Various VGIC cleanups and improvements, Christoffer Dall >>>>>>> http://comments.gmane.org/gmane.linux.ports.arm.kernel/340430 >>>>>>> [8] [RFC v2 0/9] KVM-VFIO IRQ forward control, Eric Auger >>>>>>> https://lkml.org/lkml/2014/9/1/344 >>>>>>> [9] [RFC PATCH 0/9] ARM: Forwarding physical interrupts to a guest VM, >>>>>>> Marc Zyngier >>>>>>> http://lwn.net/Articles/603514/ >>>>>>> >>>>>>> kernel pieces can be found at: >>>>>>> http://git.linaro.org/people/eric.auger/linux.git >>>>>>> (branch 3.17rc3_irqfd_forward_integ_v2) >>>>>>> QEMU pieces can be found at: >>>>>>> http://git.linaro.org/people/eric.auger/qemu.git (branch vfio_integ_v6) >>>>>>> >>>>>>> The patch series was tested on Calxeda Midway (ARMv7) where one xgmac >>>>>>> is assigned to KVM host while the second one is assigned to the guest. >>>>>>> Reworked PCI device is not tested. >>>>>>> >>>>>>> Wiki for Calxeda Midway setup: >>>>>>> https://wiki.linaro.org/LEG/Engineering/Virtualization/Platform_Device_Passthrough_on_Midway >>>>>>> >>>>>>> History: >>>>>>> >>>>>>> v5->v6: >>>>>>> - rebase on 2.1rc5 PCI code >>>>>>> - forwarded IRQ first integraton >>>>>> >>>>>> Why? Are there acceleration paths that you're concerned cannot be >>>>>> implemented or we do not already have a proof of concept for? The base >>>>>> kernel patch series you depend on is 3 months old yet this series >>>>>> continues to grow and add new dependencies. Please let's prioritize >>>>>> getting something upstream instead of adding more blockers to prevent >>>>>> that. Thanks, >>>>>> >>>>> I'm not exactly sure what this changelog line was referring to >>>>> (depending on Marc's forwarding IRQ patches?), but just want to add that >>>>> there are a number of dependencies for the GIC that need to go in as >>>>> well (should happen within a few weeks), but I think it's unlikely that >>>>> the IRQ forwarding stuff goes in for v3.18 at this point. >>>>> >>>>> It may make sense as you suggest to keep that part out of this patch set >>>>> and something merged sooner as opposed to later, but I'm too jet-lagged >>>>> to completely understand if that's going to be a horrible mess. >>>> >>>> The point is that we're on v6 of a patch series and its first non-RFC >>>> posting and we're rolling in a first pass at a QEMU implementation that >>>> depends on a contested kernel RFC, which depends on another stagnant >>>> kernel RFC. I'm fine with working on it in parallel, but give me some >>>> light at the end of the tunnel as a reviewer and maintainer that this >>>> code isn't going to live indefinitely on the mailing list. Do we really >>>> need those GIC patches do be able to have non-KVM accelerated VFIO >>>> platform device assignment? We certainly don't need IRQ forwarding. >>>> Thanks, >> >> Hi Alex, >> >> Sorry for the delay, I was travelling. >> >> I understand your impatience. I personally would be happy if we could >> envision upstreaming this patch in several steps. Let me know if it >> makes sense. >> >> STEP I: integrate 1 - 11: leads to have a non-KVM accelerated VFIO QEMU >> device. 12 can be part of it too but since it is a test feature this one >> might be dropped. just let me know what you think. > > I'd probably drop 12. Is that really something that's useful in > upstream code? It's a good use of the vfio loopback interrupt and good > testing, but do you really want to maintain it in the code? Is it > sufficient that it's been posted to the mailing list so you can find and > re-apply it if you want to do similar testing again? Hi Alex, yes I agree with you about dropping it. > >> depends on: >> QEMU: >> [1] [PATCH v2 0/9] Dynamic sysbus device allocation support, A. Graf >> http://lists.gnu.org/archive/html/qemu-ppc/2014-07/msg00047.html >> [2] [RFC v3] machvirt dynamic sysbus device instantiation, E. Auger >> [4] [RFC] vfio: migration to trace points, E. Auger >> http://lists.nongnu.org/archive/html/qemu-devel/2014-09/msg00569.html >> KERNEL: >> [5] [RFC Patch v6 0/20] VFIO support for platform devices, A. Motakis >> https://www.mail-archive.com/kvm@xxxxxxxxxxxxxxx/msg103247.html > > Ok, so let's start whittling down these dependencies. Trace points > shouldn't be any kind of blocker, you'll just need to teach me how to > use them and post a non-RFC patch ;) Yes sure I will write some instructions. I need to investigate the parser issues related to parenthesis (either fix it myself or ask Stefan's help). At this point I don't even > remember the comments for the v6 VFIO kernel support for platform > devices. I hope we're close enough that the next version can be sent as > non-RFC. It might be a good idea to pick a target kernel version and > start working towards it. v3.18 is probably not a realistic goal at > this point. I don't know about the rest, but at least the remaining > series is non-RFC and the other is only a single patch. On my side I will iterate rapidly on both [2] [RFC v3] machvirt dynamic sysbus device instantiation and [6] [PATCH v3] ARM: KVM: add irqfd support > >> Step II: integrate 13: kvm-accelerated QEMU VFIO device featuring >> iqrfd/virqfd >> >> depends on >> [7] arm/arm64: KVM: Various VGIC cleanups and improvements, C. Dall >> [6] [PATCH v3] ARM: KVM: add irqfd support, E. Auger >> https://lkml.org/lkml/2014/9/1/141 >> >> Step III: integrate > 13: kvm-accelerated QEMU VFIO device featuring >> forwarded IRQs: >> [8] [RFC v2 0/9] KVM-VFIO IRQ forward control, Eric Auger >> https://lkml.org/lkml/2014/9/1/344 >> [9] [RFC PATCH 0/9] ARM: Forwarding physical interrupts to a guest VM, >> Marc Zyngier, http://lwn.net/Articles/603514/ >> >> To me these 3 steps are quite independent from each other. > > Yep, I agree. Let's not get bogged down in letting these additional > features interfere with progress on the base support. > >> with respect to performance I think we have something reasonable now >> with irqfd and forwarded IRQ so I do not expect any new features added >> soon. >> >> from now on, I do not plan to add any new patch file to this series but >> just correct/modify according to comments & weaknesses. >> >> I Hope it clarifies plans. Please let me know. > > Thanks, it does. We have several players in the VFIO platform space and > I want to make sure we're aligned on a goal of getting code upstream, > not just posting it to the list. Thanks for the breakdown and your work > towards getting those dependencies resolved. Thanks Eric > > Alex > _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
