Re: [PATCH v5 4/7] KVM: arm64: Fix missing traps of guest accesses to the MPAM registers

[Marc Zyngier <maz@kernel.org>]

On Tue, 15 Oct 2024 14:39:20 +0100,
Joey Gouly <joey.gouly@arm.com> wrote:
> 
> @@ -204,6 +205,35 @@ static inline void __deactivate_traps_hfgxtr(struct kvm_vcpu *vcpu)
>  		__deactivate_fgt(hctxt, vcpu, kvm, HAFGRTR_EL2);
>  }
>  
> +static inline void  __activate_traps_mpam(struct kvm_vcpu *vcpu)
> +{
> +	u64 r = MPAM2_EL2_TRAPMPAM0EL1 | MPAM2_EL2_TRAPMPAM1EL1;
> +
> +	if (!cpus_support_mpam())
> +		return;
> +
> +	/* trap guest access to MPAMIDR_EL1 */
> +	if (mpam_cpus_have_mpam_hcr()) {
> +		write_sysreg_s(MPAMHCR_EL2_TRAP_MPAMIDR_EL1, SYS_MPAMHCR_EL2);
> +	} else {
> +		/* From v1.1 TIDR can trap MPAMIDR, set it unconditionally */
> +		r |= MPAM2_EL2_TIDR;
> +	}
> +
> +	write_sysreg_s(r, SYS_MPAM2_EL2);

Please use the write_sysreg_el2() accessor, so that VHE under NV has
an easier time, should we ever get there.

> +}
> +
> +static inline void __deactivate_traps_mpam(void)
> +{
> +	if (!cpus_support_mpam())
> +		return;
> +
> +	write_sysreg_s(0, SYS_MPAM2_EL2);

Same thing.

> +
> +	if (mpam_cpus_have_mpam_hcr())
> +		write_sysreg_s(MPAMHCR_HOST_FLAGS, SYS_MPAMHCR_EL2);
> +}
> +

Thanks,

	M.

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