Re: [PATCH v4 02/21] iommufd: Add iommufd_sw_map_msi()

[Andrew Jones]

On Wed, Aug 26, 2026 at 10:23:20AM +0200, Andrew Jones wrote:
> As said, iommu_dma_prepare_msi() handles one fixed MSI target. RISC-V
> has one target PA per IMSIC, so the proposed list API prepares them
> together and guarantees contiguous IOVAs. The interrupt remapping IRQ
> domain's compose callback selects the IOVA corresponding to the IMSIC PA
> selected by its parent. That selection belongs in the IRQ hierarchy.
>

That said, it should be possible to move the host MSI remapping into the
IMSIC irqdomain. I can do that for this series and see what Anup thinks
about putting it there. A per-device IOMMU irqdomain will still be needed
later for guest irqbypass through irq_set_vcpu_affinity(), but that can
wait for the next series.

Thanks,
drew