On Fri, 15 Feb 2019 11:19:09 +0000
"Dr. David Alan Gilbert" <> wrote:
> What I'm missing here is why the behaviour of the s390's traditional channel program
> matters to the design of an entirely emulated device.
I mostly wrote this up as an explanation...
>
> As long as the s390 allows:
> a) The host to map a region of HVA into GPA at an arbitrary GPA
> address
> b) Not tell the guest that (a) is RAM
> c) Find a non-RAM GPA for (a)
I think (b) and (c) are what we need to come up with a solution for...
DavidH's idea looks like a good starting point for that.
> d) Allow the guest to set up a page table pointing to (c)
> e) Discover (c) via the scheme you described
>
> Then that's all that's needed - and I'm not seeing what is different on
> s390 about a-d from any other architecture.
>
> Dave
>
>
>
> --
> Dr. David Alan Gilbert / / Manchester, UK
