Re: [PATCH v12 6/8] arm64: kvm: Expose KVM_ARM_CAP_MTE

[Marc Zyngier]

On Mon, 17 May 2021 13:32:37 +0100,
Steven Price <steven.price@arm.com> wrote:
> 
> It's now safe for the VMM to enable MTE in a guest, so expose the
> capability to user space.
> 
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
>  arch/arm64/kvm/arm.c      | 9 +++++++++
>  arch/arm64/kvm/sys_regs.c | 3 +++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 1cb39c0803a4..e89a5e275e25 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -93,6 +93,12 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
>               r = 0;
>               kvm->arch.return_nisv_io_abort_to_user = true;
>               break;
> +     case KVM_CAP_ARM_MTE:
> +             if (!system_supports_mte() || kvm->created_vcpus)
> +                     return -EINVAL;
> +             r = 0;
> +             kvm->arch.mte_enabled = true;

As far as I can tell from the architecture, this isn't valid for a
32bit guest.

        M.

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