Hi,
Given our slowly growing range of TCG emulations and the evident
interest in keeping up with modern processor architectures is it worth
having an emulation focused BoF at the up-coming KVM Forum?
Some potential topics for discussion I could think of might include:
* Progress towards heterogeneous vCPU emulation
We've been making slow progress in removing assumptions from the
various front-ends about their global nature and adding accel:TCG
abstractions and support for the translator loop. We can already have
CPUs from the same architecture family in a model. What else do we need
to do so we can have those funky ARM+RiscV+Tricore heterogeneous
models? Is it library or something else?
* External Device Models
I know this is a contentious topic given the potential for GPL
end-runs. However there are also good arguments for enabling the
testing of open source designs without having forcing the
implementation of a separate C model to test software. For example if
we hypothetically modelled a Pi Pico would it make sense to model the
PIO in C if we could just compile the Verilog for it into a SystemC
model? Would a plethora of closed device models be the inevitable
consequence of such an approach? Would it matter if we just
concentrated on supporting useful open source solutions?
* Dynamic Machine Models
While we try and avoid modelling bespoke virtual HW in QEMU
(virt/goldfish not withstanding ;-) there is obviously a desire in the
EDA space to allow such experimentation. Is this something we can
provide so aspiring HW engineers can experiment with system
architectures without having to form QEMU and learn QOM. There have
been suggestions about consuming device trees or maybe translating to
QMP calls and adding support for wiring devices together. Given the
number of forks that exist is this something that could be better
supported upstream without degenerating into messy hacks?
* A sense of time
Currently we have the fairly limited support for -icount in QEMU. At
the same time we have no desire to start expanding frontends with
the details cost models required for a more realistic sense of time to
be presented. One suggestion is to expand the TCG plugin interface to
allow for the plugin to control time allowing as much or little logic
to be pushed there as we like and freeing up frontends from ever having
to consider it.
Are any of these topics of interest? Are there any other emulation
topics people would like to discuss?
--
Alex Bennée