Re: [PATCH 1/2] target/arm: Suppress more TCG unimplemented features in ID registers

["Alex Bennée" <alex.bennee@linaro.org>]

Peter Maydell <peter.maydell@linaro.org> writes:

> We already squash the ID register field for FEAT_SPE (the Statistical
> Profiling Extension) because TCG does not implement it and if we
> advertise it to the guest the guest will crash trying to look at
> non-existent system registers.  Do the same for some other features
> which a real hardware Neoverse-V1 implements but which TCG doesn't:
>  * FEAT_TRF (Self-hosted Trace Extension)
>  * Trace Macrocell system register access
>  * Memory mapped trace
>  * FEAT_AMU (Activity Monitors Extension)
>  * FEAT_MPAM (Memory Partitioning and Monitoring Extension)
>  * FEAT_NV (Nested Virtualization)
>
> Most of these, like FEAT_SPE, are "introspection/trace" type features
> which QEMU is unlikely to ever implement.  The odd-one-out here is
> FEAT_NV -- we could implement that and at some point we probably
> will.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro