Re: [RFC PATCH 1/3] iommu/riscv: Add guest IMSIC GPA mapping helpers

[Jason Gunthorpe]

On Sat, Oct 10, 2026 at 07:18:37PM +0800, fangyu.yu@xxxxxxxxxxxxxxxxx wrote:
> This is not a generic page-table operation. It is a special
> requirement of RISC-V IOMMU IRQ forwarding (irqbypass) on
> implementations without an MSI page table: the guest IMSIC GPA
> must be mapped into the second-stage domain, and when a vCPU's
> VS-file host page migrates, its leaf must be replaced atomically.

I think you can add an atomic PTE replace operation to generic_pt,
that should be fine.

Jason