Re: [PATCH 15/21] KVM: TDX: Implement hook to get max mapping level of private pages

[Paolo Bonzini]

On 9/4/24 05:07, Rick Edgecombe wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> Implement hook private_max_mapping_level for TDX to let TDP MMU core get
> max mapping level of private pages.
>
> The value is hard coded to 4K for no huge page support for now.
>
> Co-developed-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
> Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
> ---
> TDX MMU part 2 v1:
>   - Split from the big patch "KVM: TDX: TDP MMU TDX support".
>   - Fix missing tdx_gmem_private_max_mapping_level() implementation for
>     !CONFIG_INTEL_TDX_HOST
>
> v19:
>   - Use gmem_max_level callback, delete tdp_max_page_level.
> ---
>   arch/x86/kvm/vmx/main.c    | 10 ++++++++++
>   arch/x86/kvm/vmx/tdx.c     |  5 +++++
>   arch/x86/kvm/vmx/x86_ops.h |  2 ++
>   3 files changed, 17 insertions(+)
>
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index bf6fd5cca1d6..5d43b44e2467 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -184,6 +184,14 @@ static int vt_vcpu_mem_enc_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
>   	return tdx_vcpu_ioctl(vcpu, argp);
>   }
>   
> +static int vt_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn)
> +{
> +	if (is_td(kvm))
> +		return tdx_gmem_private_max_mapping_level(kvm, pfn);
> +
> +	return 0;
> +}
> +
>   #define VMX_REQUIRED_APICV_INHIBITS				\
>   	(BIT(APICV_INHIBIT_REASON_DISABLED) |			\
>   	 BIT(APICV_INHIBIT_REASON_ABSENT) |			\
> @@ -337,6 +345,8 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
>   
>   	.mem_enc_ioctl = vt_mem_enc_ioctl,
>   	.vcpu_mem_enc_ioctl = vt_vcpu_mem_enc_ioctl,
> +
> +	.private_max_mapping_level = vt_gmem_private_max_mapping_level
>   };
>   
>   struct kvm_x86_init_ops vt_init_ops __initdata = {
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index b8cd5a629a80..59b627b45475 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -1582,6 +1582,11 @@ int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
>   	return ret;
>   }
>   
> +int tdx_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn)
> +{
> +	return PG_LEVEL_4K;
> +}
> +
>   #define KVM_SUPPORTED_TD_ATTRS (TDX_TD_ATTR_SEPT_VE_DISABLE)
>   
>   static int __init setup_kvm_tdx_caps(void)
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index d1db807b793a..66829413797d 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -142,6 +142,7 @@ int tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
>   
>   void tdx_flush_tlb_current(struct kvm_vcpu *vcpu);
>   void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level);
> +int tdx_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn);
>   #else
>   static inline int tdx_vm_init(struct kvm *kvm) { return -EOPNOTSUPP; }
>   static inline void tdx_mmu_release_hkid(struct kvm *kvm) {}
> @@ -185,6 +186,7 @@ static inline int tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
>   
>   static inline void tdx_flush_tlb_current(struct kvm_vcpu *vcpu) {}
>   static inline void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level) {}
> +static inline int tdx_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn) { return 0; }
>   #endif
>   
>   #endif /* __KVM_X86_VMX_X86_OPS_H */

Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>