KVM/nVMX: Use kvm_vcpu_map for accessing the enlightened VMCS

Use kvm_vcpu_map for accessing the enlightened VMCS since using
kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
a "struct page".
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/nested.c

@@ -193,10 +193,8 @@ static inline void nested_release_evmcs(struct kvm_vcpu *vcpu)
 	if (!vmx->nested.hv_evmcs)
 		return;
 
-	kunmap(vmx->nested.hv_evmcs_page);
-	kvm_release_page_dirty(vmx->nested.hv_evmcs_page);
+	kvm_vcpu_unmap(vcpu, &vmx->nested.hv_evmcs_map, true);
 	vmx->nested.hv_evmcs_vmptr = -1ull;
-	vmx->nested.hv_evmcs_page = NULL;
 	vmx->nested.hv_evmcs = NULL;
 }
 
@@ -1786,13 +1784,11 @@ static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu,
 
 		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)))
+		if (kvm_vcpu_map(vcpu, gpa_to_gfn(assist_page.current_nested_vmcs),
+				 &vmx->nested.hv_evmcs_map))
 			return 0;
 
-		vmx->nested.hv_evmcs = kmap(vmx->nested.hv_evmcs_page);
+		vmx->nested.hv_evmcs = vmx->nested.hv_evmcs_map.hva;
 
 		/*
 		 * Currently, KVM only supports eVMCS version 1
@@ -4350,7 +4346,7 @@ static int handle_vmclear(struct kvm_vcpu *vcpu)
 		return nested_vmx_failValid(vcpu,
 			VMXERR_VMCLEAR_VMXON_POINTER);
 
-	if (vmx->nested.hv_evmcs_page) {
+	if (vmx->nested.hv_evmcs_map.hva) {
 		if (vmptr == vmx->nested.hv_evmcs_vmptr)
 			nested_release_evmcs(vcpu);
 	} else {

arch/x86/kvm/vmx/vmx.h

@@ -172,7 +172,7 @@ struct nested_vmx {
 	} smm;
 
 	gpa_t hv_evmcs_vmptr;
-	struct page *hv_evmcs_page;
+	struct kvm_host_map hv_evmcs_map;
 	struct hv_enlightened_vmcs *hv_evmcs;
 };