On Fri, Nov 01, 2024 at 06:35:23PM +0000, Shameerali Kolothum Thodi wrote: > > @Shameer, > > Do you have some update on the pluggable smmuv3 module? > > I have a bare minimum prototype code that works with a pluggable smmuv3. > > ... > -device pxb-pcie,id=pcie.1,bus_nr=2,bus=pcie.0 \ > -device pcie-root-port,id=pcie.port1,bus=pcie.1 \ > -device arm-smmuv3-nested,id=smmuv1,pci-bus=pcie.1 \ > -device vfio-pci-nohotplug,host=0000:75:00.1,bus=pcie.port1,iommufd=iommufd0 \ > -device pxb-pcie,id=pcie.2,bus_nr=8,bus=pcie.0 \ > -device pcie-root-port,id=pcie.port2,bus=pcie.2,chassis=8 \ > -device arm-smmuv3-nested,id=smmuv2,pci-bus=pcie.2 \ > -device vfio-pci-nohotplug,host=0000:7d:02.1,bus=pcie.port2,iommufd=iommufd0 \ > ... > > Something like above can now boot a Guest with the latest kernel. But I am not > sure it actually works correctly. I need a bit more time to update this and > carry > out some tests. Will target that in Nov.
That looks nice to me! Thanks for the update. > > Updates on my side: > > 1) I have kept uAPI updated to the latest version and verified too. > > There should be some polishing changes depending on how the basic > > nesting infrastructure would look like from Intel/Duan's work. > > 2) I got some help from NVIDIA folks for the libvirt task. And they > > have done some drafting and are now verifying the PCI topology > > with "iommu=none". > > > > Once the pluggable smmuv3 module is ready to test, we will make some > > change to libvirt for that and drop the auto-assigning patches from > > the VIRT code, so as to converge for a libvirt+QEMU test. > > One query I have is, do Qemu still need to check whether the VFIO devices are > assigned correctly behind the nested vSMMUv3 w.r.t the phys SMMUv3s or not? > Or we can just trust whatever the user/libvirt specifies? That's a good point. I assume ideally QEMU should do something, though that would be somewhat duplicated with libvirt. > (I think even if we don't explicitly check, at present it will eventually > fail in s2 > HWPT attach for the viommu if it belongs to a different phys SMMUv3). Yes. That's what we have. Perhaps simply print something like: "is the device assigned to the correct arm-smmuv3-nested/pxb?" ? Thanks Nicolin
