sandbox: vm: add page splitting, merging, and allocation

sandbox/base/memory_test.c

@@ -174,6 +174,24 @@ int memory_test(void)
 	printf("all pages:\n");
 	print_all_pages();
 
+	vm_page_t *pg = vm_page_alloc(VM_PAGE_128K, 0);
+	printf("allocated 128K at 0x%lx\n", vm_page_get_paddr(pg));
+
+	vm_page_t *a, *b;
+	if (vm_page_split(pg, &a, &b) == 0) {
+		printf("split page into two 64K pages at 0x%lx and 0x%lx:\n", vm_page_get_paddr(a), vm_page_get_paddr(b));
+
+		assert(a->p_flags & VM_PAGE_HEAD);
+		assert(b->p_flags & VM_PAGE_HEAD);
+
+		size_t nr_frames = vm_page_order_to_pages(VM_PAGE_128K);
+		for (size_t i = 0; i < nr_frames; i++) {
+			printf("  0x%lx: order:%u, flags:0x%x\n", vm_page_get_paddr(a + i), a[i].p_order, a[i].p_flags);
+			assert(a[i].p_flags & VM_PAGE_HUGE);
+			assert((a[i].p_flags & VM_PAGE_RESERVED) == 0);
+		}
+	}
+
 	munmap(system_memory, MB_TO_BYTES(MEMORY_SIZE_MB));
 	return 0;
 }