SMMU Stage 2 translation in QEMU

[shashi.mallela@linaro.org]

Hi All,

I am trying to understand the approach required for an emulated SMMU to
convert IPAs(from each qemu guest) to PAs(respective host addresses)
using stage 2 tables.

The questions i have are:-

1) Since SMMU stage 2 tables are expected to be created and managed by
a hypervisor,if there is no kvm support,who is responsible to create
the stage 2 tables in host memory? is it even a valid use case to
consider smmu stage 2 support with no hypervisor present?

2) with SMMU emulated by qemu:-
a) who is responsible for hosting and programming the stage 2 table
base address registers? 
b) what are the APIs available in qemu to access the stage 2 tables?
(will address_space_ API variants apply here?)

3) if each qemu instance (for a guest) emulates an SMMU,will there be a
need to protect concurrent access of stage 2 table(in host) by each of
the SMMUs?

Thanks
Shashi