Re: SMMU Stage 2 translation in QEMU

[shashi.mallela@linaro.org]

I am referring to the latter,"purely emulated QEMU with an emulated
SMMU that handles accesses to emulated devices"

Thanks
Shashi

On Fri, 2021-09-10 at 10:25 +0100, Peter Maydell wrote:
> On Thu, 9 Sept 2021 at 21:18, <shashi.mallela@linaro.org> wrote:
> > 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?
> 
> So what exactly is the use case you're talking about here?
> Do you mean "purely emulated QEMU, but using a host hardware
> IOMMU to do device passthrough of host devices to the guest"?
> Or do you mean "purely emulated QEMU with an emulated SMMU
> that handles accesses to emulated devices" ?
> 
> thanks
> -- PMM