Question about RISCV IOMMU irqbypass patch series

[Xu Lu]

Hi Andrew,

Thanks for your brilliant job on the RISCV IOMMU irqbypass patch
series[1]. I have rebased it on v6.18 and successfully passed through
a nvme device to VM. But I still have some questions about it.

1. It seems "irqdomain->host_data->domain" can be NULL for blocking or
identity domain. So it's better to check whether it's NULL in
riscv_iommu_ir_irq_domain_alloc_irqs or
riscv_iommu_ir_irq_domain_free_irqs functions. Otherwise page fault
can happen.

2. It seems you are using the first stage iommu page table even for
gpa->spa, what if a VM needs an vIOMMU? Or did I miss something?

[1] https://lore.kernel.org/all/20250920203851.2205115-20-ajones@ventanamicro.com/

Best regards,
Xu Lu