[Qemu-devel] How to decide the value of Host Address Width in ACPI DMAR table

[Le Tan]

Hi,
I am doing Intel IOMMU emulation for q35. I need to add a DMAR table
to ACPI. There is one field in the DMAR table called "Host Address
Width", which indicates the maximum DMA physical addressability
supported by this platform. I am not sure what this value should be
and how to get this value. What is the best way to decide the value of
HAW?
Any suggestion is appreciated. :)
Thanks very much!

Regards,
Le Tan