KVM: TDX: Implement hook to get max mapping level of private pages

JIRA: https://issues.redhat.com/browse/RHEL-15711
Upstream status: https://git.kernel.org/pub/scm/virt/kvm/kvm.git

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.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Co-developed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241112073816.22256-1-yan.y.zhao@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 0036b87)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: bonzini

arch/x86/kvm/vmx/main.c

@@ -174,6 +174,14 @@ 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_DISABLE)|			\
 	 BIT(APICV_INHIBIT_REASON_ABSENT) |			\
@@ -330,6 +338,8 @@ 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 = {

arch/x86/kvm/vmx/tdx.c

@@ -1636,6 +1636,11 @@ 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;
+}
+
 static int tdx_online_cpu(unsigned int cpu)
 {
 	unsigned long flags;

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_flush_tlb_all(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) {}
@@ -184,6 +185,7 @@ 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_flush_tlb_all(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 */