sandbox: vm: organise pages into zoned blocks

sandbox/vm/vm_page.c

@@ -1,7 +1,87 @@
+#include <socks/types.h>
+#include <socks/memblock.h>
 #include <socks/vm.h>
 #include <string.h>
+#include <stdio.h>
 
-void vm_page_init(vm_page_t *pg)
+/* array of pages, one for each physical page frame present in RAM */
+static vm_page_t *page_array = NULL;
+
+/* number of pages stored in page_array */
+static size_t page_array_count = 0;
+
+/* Pre-calculated page order -> size conversion table */
+static size_t page_order_bytes[] = {
+	[VM_PAGE_4K]   = 0x1000,
+	[VM_PAGE_8K]   = 0x2000,
+	[VM_PAGE_16K]  = 0x4000,
+	[VM_PAGE_32K]  = 0x8000,
+	[VM_PAGE_64K]  = 0x10000,
+	[VM_PAGE_128K] = 0x20000,
+	[VM_PAGE_256K] = 0x40000,
+	[VM_PAGE_512K] = 0x80000,
+	[VM_PAGE_1M]   = 0x100000,
+	[VM_PAGE_2M]   = 0x200000,
+	[VM_PAGE_4M]   = 0x400000,
+	[VM_PAGE_8M]   = 0x800000,
+	[VM_PAGE_16M]  = 0x1000000,
+	[VM_PAGE_32M]  = 0x2000000,
+	[VM_PAGE_64M]  = 0x4000000,
+	[VM_PAGE_128M] = 0x8000000,
+	[VM_PAGE_256M] = 0x10000000,
+	[VM_PAGE_512M] = 0x20000000,
+	[VM_PAGE_1G]   = 0x40000000,
+};
+
+void vm_page_init_array()
 {
-	memset(pg, 0x0, sizeof *pg);
+	size_t pmem_size = 0;
+
+	memblock_iter_t it;
+	for_each_mem_range (&it, 0x0, UINTPTR_MAX) {
+		if (pmem_size < it.it_limit + 1) {
+			pmem_size = it.it_limit + 1;
+		}
+	}
+
+	size_t nr_pages = pmem_size / VM_PAGE_SIZE;
+	if (pmem_size % VM_PAGE_SIZE) {
+		nr_pages++;
+	}
+
+	page_array = memblock_alloc(sizeof(vm_page_t) * nr_pages);
+	page_array_count = nr_pages;
+	printf("page_array covers 0x%zx bytes, %zu page frames\n", pmem_size, pmem_size / VM_PAGE_SIZE);
+	printf("page_array is %zu bytes long\n", sizeof(vm_page_t) * nr_pages);
+
+	for (size_t i = 0; i < nr_pages; i++) {
+		memset(&page_array[i], 0x0, sizeof page_array[i]);
+	}
+
+	size_t nr_reserved = 0;
+	for_each_reserved_mem_range(&it, 0x0, UINTPTR_MAX) {
+		for (uintptr_t i = it.it_base; i < it.it_limit; i += VM_PAGE_SIZE) {
+			size_t pfn = i / VM_PAGE_SIZE;
+
+			page_array[pfn].p_flags |= VM_PAGE_RESERVED;
+			nr_reserved++;
+		}
+	}
+
+	printf("%zu reserved page frames\n", nr_reserved);
+}
+
+vm_page_t *vm_page_get(phys_addr_t addr)
+{
+	size_t pfn = addr / VM_PAGE_SIZE;
+	return pfn < page_array_count ? &page_array[pfn] : NULL;
+}
+
+size_t vm_page_order_to_bytes(vm_page_order_t order)
+{
+	if (order < 0 || order > VM_PAGE_MAX_ORDER) {
+		return 0;
+	}
+
+	return page_order_bytes[order];
 }