KVM: selftests: Refactor nested_map() to specify target level

Refactor nested_map() to specify that it explicityl wants 4K mappings
(the existing behavior) and push the implementation down into
__nested_map(), which can be used in subsequent commits to create huge
page mappings.

No function change intended.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220520233249.3776001-5-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/lib/x86_64/vmx.c

@@ -486,6 +486,7 @@ void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
  *   nested_paddr - Nested guest physical address to map
  *   paddr - VM Physical Address
  *   size - The size of the range to map
+ *   level - The level at which to map the range
  *
  * Output Args: None
  *
@@ -494,22 +495,29 @@ void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
  * Within the VM given by vm, creates a nested guest translation for the
  * page range starting at nested_paddr to the page range starting at paddr.
  */
-void nested_map(struct vmx_pages *vmx, struct kvm_vm *vm,
-		uint64_t nested_paddr, uint64_t paddr, uint64_t size)
+void __nested_map(struct vmx_pages *vmx, struct kvm_vm *vm,
+		  uint64_t nested_paddr, uint64_t paddr, uint64_t size,
+		  int level)
 {
-	size_t page_size = vm->page_size;
+	size_t page_size = PG_LEVEL_SIZE(level);
 	size_t npages = size / page_size;
 
 	TEST_ASSERT(nested_paddr + size > nested_paddr, "Vaddr overflow");
 	TEST_ASSERT(paddr + size > paddr, "Paddr overflow");
 
 	while (npages--) {
-		nested_pg_map(vmx, vm, nested_paddr, paddr);
+		__nested_pg_map(vmx, vm, nested_paddr, paddr, level);
 		nested_paddr += page_size;
 		paddr += page_size;
 	}
 }
 
+void nested_map(struct vmx_pages *vmx, struct kvm_vm *vm,
+		uint64_t nested_paddr, uint64_t paddr, uint64_t size)
+{
+	__nested_map(vmx, vm, nested_paddr, paddr, size, PG_LEVEL_4K);
+}
+
 /* Prepare an identity extended page table that maps all the
  * physical pages in VM.
  */