+/*
+ * This is an equivalent of the nested hypervisor executing the vmptrld
+ * instruction.
+ */
+static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ struct hv_vp_assist_page assist_page;
+
+ if (likely(!vmx->nested.enlightened_vmcs_enabled))
+ return 1;
+
+ if (unlikely(!kvm_hv_get_assist_page(vcpu, &assist_page)))
+ return 1;
+
+ if (unlikely(!assist_page.enlighten_vmentry))
+ return 1;
+
+ if (unlikely(assist_page.current_nested_vmcs !=
+ vmx->nested.hv_evmcs_vmptr)) {
+
+ if (!vmx->nested.hv_evmcs)
+ vmx->nested.current_vmptr = -1ull;
+
+ nested_release_evmcs(vcpu);
+
+ vmx->nested.hv_evmcs_page = kvm_vcpu_gpa_to_page(
+ vcpu, assist_page.current_nested_vmcs);
+
+ if (unlikely(is_error_page(vmx->nested.hv_evmcs_page)))
+ return 0;
+
+ vmx->nested.hv_evmcs = kmap(vmx->nested.hv_evmcs_page);
+
+ if (vmx->nested.hv_evmcs->revision_id != VMCS12_REVISION) {
+ nested_release_evmcs(vcpu);
+ return 0;
+ }
+
+ vmx->nested.dirty_vmcs12 = true;
+ /*
+ * As we keep L2 state for one guest only 'hv_clean_fields' mask
+ * can't be used when we switch between them. Reset it here for
+ * simplicity.
+ */
+ vmx->nested.hv_evmcs->hv_clean_fields &=
+ ~HV_VMX_ENLIGHTENED_CLEAN_FIELD_ALL;
+ vmx->nested.hv_evmcs_vmptr = assist_page.current_nested_vmcs;
+
+ /*
+ * Unlike normal vmcs12, enlightened vmcs12 is not fully
+ * reloaded from guest's memory (read only fields, fields not
+ * present in struct hv_enlightened_vmcs, ...). Make sure there
+ * are no leftovers.
+ */
+ memset(vmx->nested.cached_vmcs12, 0,
+ sizeof(*vmx->nested.cached_vmcs12));
+
+ }
+ return 1;
+}
+