Re: [PATCH v2 0/7] hw/arm/smmuv3-accel: Resolve AUTO properties

["Cédric Le Goater" <clg@redhat.com>]

Hello Nathan,

On 4/22/26 22:43, Nathan Chen wrote:
> Hi,
> 
> This series introduces support for resolving 'auto' for arm-smmuv3
> accelerated mode's ATS, RIL, SSIDSIZE, and OAS feature properties based
> on host IOMMU capabilities. This is dependent on the series [0] for
> changing these property types to accept 'auto' values.
> 
> Accelerated SMMUv3 Address Translation Services support is derived from
> IDR0, Range Invalidation support is derived from IDR3, Substream ID
> size is derived from IDR1, and output address space is derived from
> IDR5.
> 
> The default values are set to 'auto' for all properties. If accel=off
> and the values are set to 'auto' or are omitted and resolve to 'auto',
> the default property values defined in smmuv3_init_id_regs() for OAS
> and RIL will remain unchanged, while SSIDSIZE and ATS values will
> remain initialized at 0.
> 
> A complete branch can be found here:
> https://github.com/NathanChenNVIDIA/qemu/tree/smmuv3-accel-auto-resolve-v2
> 
> Please take a look and let me know your feedback.
> 
> Thanks,
> Nathan
> 
> [0] https://lore.kernel.org/qemu-arm/20260323182454.1416110-1-nathanc@nvidia.com/
> 
> Example usage:
> qemu-system-aarch64 \
>    -object iommufd,id=iommufd0 \
>    -machine virt,accel=kvm,gic-version=3,ras=on,highmem-mmio-size=4T \
>    -cpu host -smp cpus=4 -m size=16G -nographic \
>    -object memory-backend-ram,size=16G,id=m0 \
>    -numa node,memdev=m0,cpus=0-3,nodeid=0 \
>    -numa node,nodeid=1 -numa node,nodeid=2 -numa node,nodeid=3 -numa node,nodeid=4 \
>    -numa node,nodeid=5 -numa node,nodeid=6 -numa node,nodeid=7 -numa node,nodeid=8 \
>    -device pxb-pcie,id=pcie.1,bus_nr=1,bus=pcie.0,numa_node=0 \
>    -device arm-smmuv3,primary-bus=pcie.1,id=smmuv3.1,accel=on,ats=auto,ssidsize=auto,ril=auto,oas=auto \
>    -device pcie-root-port,id=pcie.port1,bus=pcie.1,chassis=1,io-reserve=0 \
>    -device vfio-pci-nohotplug,host=0009:06:00.0,bus=pcie.port1,rombar=0,id=dev0,iommufd=iommufd0,ats=auto \
>    -object acpi-generic-initiator,id=gi0,pci-dev=dev0,node=1 \
>    -object acpi-generic-initiator,id=gi1,pci-dev=dev0,node=2 \
>    -object acpi-generic-initiator,id=gi2,pci-dev=dev0,node=3 \
>    -object acpi-generic-initiator,id=gi3,pci-dev=dev0,node=4 \
>    -object acpi-generic-initiator,id=gi4,pci-dev=dev0,node=5 \
>    -object acpi-generic-initiator,id=gi5,pci-dev=dev0,node=6 \
>    -object acpi-generic-initiator,id=gi6,pci-dev=dev0,node=7 \
>    -object acpi-generic-initiator,id=gi7,pci-dev=dev0,node=8 \
>    -bios /usr/share/AAVMF/AAVMF_CODE.fd \
>    -device nvme,drive=nvme0,serial=deadbeaf1,bus=pcie.0 \
>    -drive file=/var/lib/libvirt/images/guest.qcow2,index=0,media=disk,format=qcow2,if=none,id=nvme0 \
>    -device e1000,romfile=/usr/local/share/qemu/efi-e1000.rom,netdev=net0,bus=pcie.0 \
>    -netdev user,id=net0,hostfwd=tcp::5558-:22,hostfwd=tcp::5586-:5586
> 
> Testing:
> Basic sanity testing was performed on an NVIDIA Grace platform with GPU
> device assignment and running CUDA test apps on the guest. Observed the
> feature properties being set based on host IOMMU capabilities.
> Verified that the VM boot will fail without a cold-plugged device, and
> that a hot-plugged device re-uses the resolved values from the initial
> cold-plug. Additional testing and feedback are welcome.

It is helpful to have a changelog between different versions of
the same series of patches.

So, the linux headers and vfio update are not required anymore ?

Thanks,

C.


> 
> Nathan Chen (7):
>    hw/arm/smmuv3-accel: Add helper for resolving auto parameters
>    hw/arm/smmuv3-accel: Implement "auto" value for "ats"
>    hw/arm/smmuv3-accel: Implement "auto" value for "ril"
>    hw/arm/smmuv3-accel: Implement "auto" value for "ssidsize"
>    hw/arm/smmuv3-accel: Implement "auto" value for "oas"
>    hw/arm/smmuv3: Set default ats, ril, ssidsize, oas to auto
>    qemu-options.hx: Support "auto" for accel SMMUv3 properties
> 
>   hw/arm/smmuv3-accel.c   | 80 ++++++++++++++++++++++++++++++++++++++++-
>   hw/arm/smmuv3-accel.h   |  2 ++
>   hw/arm/smmuv3.c         | 63 +++++++++++++++-----------------
>   hw/core/machine.c       |  8 +++++
>   include/hw/arm/smmuv3.h |  2 ++
>   qemu-options.hx         | 33 +++++++++++------
>   6 files changed, 143 insertions(+), 45 deletions(-)
>