[PATCH v2 2/5] KVM: arm64: Force trap of GMID_EL1 when the guest doesn't have MTE

[Yao Yuan]

Hi Marc,

On Wed, Nov 26, 2025 at 03:59:48PM +0800, Marc Zyngier wrote:
> If our host has MTE, but the guest doesn't, make sure we set HCR_EL2.TID5
> to force GMID_EL1 being trapped.
>
> Reviewed-by: Joey Gouly <joey.gouly at arm.com>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  arch/arm64/kvm/sys_regs.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 9e4c46fbfd802..2ca6862e935b5 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -5561,6 +5561,8 @@ static void vcpu_set_hcr(struct kvm_vcpu *vcpu)
>
>  	if (kvm_has_mte(vcpu->kvm))
>  		vcpu->arch.hcr_el2 |= HCR_ATA;
> +	else if (id_aa64pfr1_mte(read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1)))
> +		vcpu->arch.hcr_el2 |= HCR_TID5;

Reviewed-by: Yuan Yao <yaoyuan at linux.alibaba.com>

>
>  	/*
>  	 * In the absence of FGT, we cannot independently trap TLBI
> --
> 2.47.3
>