On Thu, 2023-01-12 at 08:31 -0800, isaku.yamahata@intel.com wrote:
> From: Isaku Yamahata <isaku.yamahata@intel.com>
>
> Require the TDP MMU for guest TDs, the so called "shadow" MMU does not
> support mapping guest private memory, i.e. does not support Secure-EPT.
It's not accurate. Legacy MMU using EPT can also support. We just choose to
not support. Please revisit.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
> arch/x86/kvm/mmu/tdp_mmu.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index fdcff390ebc2..6c3ce4121a46 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -27,6 +27,13 @@ int kvm_mmu_init_tdp_mmu(struct kvm *kvm)
> if (kvm->arch.vm_type == KVM_X86_TDX_VM && !enable_mmio_caching)
> return -EOPNOTSUPP;
>
> + /*
> + * Because only the TDP MMU supports TDX, require the TDP MMU for guest
> + * TDs.
> + */
> + if (kvm->arch.vm_type == KVM_X86_TDX_VM && !tdp_enabled)
> + return -EOPNOTSUPP;
> +
> if (!tdp_enabled || !READ_ONCE(tdp_mmu_enabled))
> return 0;
>