RE: nested-smmuv3 topic for QEMU/libvirt, Nov 2024

[Shameerali Kolothum Thodi via <qemu-devel@nongnu.org>]

> -----Original Message-----
> From: Andrea Bolognani <abologna@redhat.com>
> Sent: Wednesday, November 20, 2024 9:14 PM
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> Cc: Nicolin Chen <nicolinc@nvidia.com>; Eric Auger
> <eric.auger@redhat.com>; Mostafa Saleh <smostafa@google.com>; qemu-
> arm@nongnu.org; qemu-devel@nongnu.org; Peter Maydell
> <peter.maydell@linaro.org>; Jason Gunthorpe <jgg@nvidia.com>; Jean-
> Philippe Brucker <jean-philippe@linaro.org>; Moritz Fischer
> <mdf@kernel.org>; Michael Shavit <mshavit@google.com>; Michael S.
> Tsirkin <mst@redhat.com>; Peter Xu <peterx@redhat.com>; Zhangfei Gao
> <zhangfei.gao@linaro.org>; nathanc@nvidia.com; arighi@nvidia.com;
> ianm@nvidia.com; jan@nvidia.com; mochs@nvidia.com
> Subject: Re: nested-smmuv3 topic for QEMU/libvirt, Nov 2024
> 
> On Fri, Nov 01, 2024 at 06:35:23PM +0000, Shameerali Kolothum Thodi
> wrote:
> > 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 \
> 
> Silly bit of feedback on the interface, but why is the
> arm-smmuv3-nested property called "pci-bus" instead of just "bus"?
> 
> All other devices that need to refer to an existing PCI bus use the
> latter. Is there a reason for this specific one to diverge?

Nope. This will be changed to "bus" in next respin.

Thanks,
Shameer