Re: [PATCH v3 3/7] arm64/kvm: disable access to AMU registers from kvm guests

[Valentin Schneider]

On 11/02/2020 18:45, Ionela Voinescu wrote:
> Access to the AMU counters should be disabled by default in kvm guests,
> as information from the counters might reveal activity in other guests
> or activity on the host.
> 
> Therefore, disable access to AMU registers from EL0 and EL1 in kvm
> guests by:
>  - Hiding the presence of the extension in the feature register
>    (SYS_ID_AA64PFR0_EL1) on the VCPU.
>  - Disabling access to the AMU registers before switching to the guest.
>  - Trapping accesses and injecting an undefined instruction into the
>    guest.
> 
> Signed-off-by: Ionela Voinescu <ionela.voinescu@xxxxxxx>
> Cc: Marc Zyngier <maz@xxxxxxxxxx>
> Cc: James Morse <james.morse@xxxxxxx>
> Cc: Julien Thierry <julien.thierry.kdev@xxxxxxxxx>
> Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>

Reviewed-by: Valentin Schneider <valentin.schneider@xxxxxxx>