Re: [RFC 5/8] KVM: arm64: Explicitly handle MDSELR_EL1 traps as UNDEFINED

From: Marc Zyngier
Date: Fri Apr 05 2024 - 06:15:46 EST


On Fri, 05 Apr 2024 09:00:05 +0100,
Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote:
>
> Currently read_sanitised_id_aa64dfr0_el1() caps the ID_AA64DFR0.DebugVer to
> ID_AA64DFR0_DebugVer_V8P8, resulting in FEAT_Debugv8p9 not being exposed to
> the guest. MDSELR_EL1 register access in the guest, is currently trapped by
> the existing configuration of the fine-grained traps.

Please add support for the HDFGxTR2_EL2 registers in the trap routing
arrays, add support for the corresponding FGUs in the corresponding
structure, and condition the UNDEF on the lack of *guest* support for
the feature.

In short, implement the architecture as described in the pseudocode,
and not a cheap shortcut.

Thanks,

M.

--
Without deviation from the norm, progress is not possible.