[PATCH] iommu/riscv: Add dependency between iommu and devices

[Sunil V L]

On Mon, Jun 8, 2026 at 11:52 AM <wang.yechao255 at zte.com.cn> wrote:
>
> > >
> > > From: Wang Yechao <wang.yechao255 at zte.com.cn>
> > >
> > > Commit 9156585280f1 ("ACPI: RIMT: Add dependency between iommu and
> > > devices") adds the dependency between iommu and devices on ACPI
> > > systems. On devicetree systems, the incorrect removal order also
> > > occurs.
> > >
> > Interesting. Why is it not handled by the fw_devlink infrastructure in DT?
> >
> > Thanks,
> > Sunil
>
> Thank you. I have noticed that commit e149573b2f84 ("of: property: Add device
> link support for "iommu-map"") adds support for "iommu-map" to the device link
> supplier bindings, so that probing of PCI devices can be deferred until after
> the IOMMU is available.
>
> The QEMU RISC-V virt machine currently lacks the "iommu-map" property for the
> PCIe bus when the iommu-pci device is used, which leads to this issue. Therefore,
> I believe the correct fix is to add the "iommu-map" property for PCIe in QEMU.
>
For PCI IOMMU, the dependency should be automatically taken care since iommu
should always be the first device in the hierarchy and scanned first.