Re: [PATCH v4 13/21] iommu/riscv: Preserve MSI IOVA state across domain replacement
Andrew Jones <[email protected]>
| Newsgroups | org.infradead.lists.linux-riscv,dev.linux.lists.iommu,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <wshoqx3xyz7f2jmhgbyzpkm4ppl64olswhw5u6dye7nmomkari@j2zg5ecuvsmg> |
On Thu, Aug 20, 2026 at 06:52:04PM -0300, Jason Gunthorpe wrote:
> On Thu, Aug 20, 2026 at 11:41:42PM +0200, Andrew Jones wrote:
> > MSI IOVAs belong to a paging domain, but iommufd may replace a device's
> > domain while its interrupts remain allocated. Waiting for another IRQ
> > allocation to populate the new table would leave existing interrupts
> > without valid MSI IOVAs.
>
> ???
>
> iommufd is supposed to handle all of this itself, that is what commit
> 40f5175d0eb7 ("iommufd: Implement sw_msi support natively")
>
> is doing?
>
> The whole point of that commit was so drivers don't have to deal with
> this at all.
>
This driver relies on that support. iommufd installs all required MSI
mappings in the incoming HWPT before attach. The additional driver work
is to populate the PA-to-IOVA lookup table riscv needs in MSI composition
on IRQ affinity changes.
Thanks,
drew
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