1 files changed, 50 insertions, 0 deletions
diff --git a/src/vmm.cc b/src/vmm.cc
index 346e6ab..483f02f 100644
--- a/src/vmm.cc
+++ b/src/vmm.cc
@@ -1,3 +1,4 @@
+#include "vmm.h"
 #include <stdlib.h>
 
 typedef void (*constructor)();
@@ -47,3 +48,52 @@ void dump_address() {
          " end: ", uhex{reinterpret_cast<uint32_t>(&end_bss)}, '\n');
 }
 }  // extern "C"
+
+/* boot.S page directory and kernel page table */
+extern uint32_t kernel_pagedir;
+extern uint32_t kernel_ptable0;
+
+constexpr uint32_t to_vma(uint32_t page_dir_address) {
+  page_dir_address &= 0xfffff000;
+  page_dir_address += 0xc0000000;
+  page_dir_address -= 0x00400000;
+  return page_dir_address;
+}
+
+vmm::vmm(uint32_t* addr) : directory{(addr == nullptr) ? &kernel_pagedir : addr} {
+  printk("page directory is at ", uhex{reinterpret_cast<uint32_t>(directory)}, '\n');
+  printk("page table 768       ", uhex{reinterpret_cast<uint32_t>(directory[768])}, '\n');
+  printk("page table 768 vma   ", uhex{to_vma(reinterpret_cast<uint32_t>(directory[768]))}, '\n');
+  printk("kernel_ptable0 is at ", uhex{reinterpret_cast<uint32_t>(&kernel_ptable0)}, '\n');
+
+  uint32_t* page = reinterpret_cast<uint32_t*>(&kernel_ptable0);
+  for (size_t i = 0; i < 32; ++i) {
+    printk(uhex{page[i] & 0xfffff000}, ' ');
+    if (i % 4 == 3) printk('\n');
+  }
+}
+
+uint32_t vmm::map(uint32_t phys_addr, uint32_t dest) {
+  const auto phys_offset = phys_addr % 4096;
+  const auto phys_page = phys_addr - phys_offset;
+
+  const auto table = table_id(dest);
+  const auto page = page_id(dest - table * 4 * 1024 * 1024);
+
+  printk("phys_addr page: ", uhex{phys_page}, '\n');
+  printk("        offset: ", uhex{phys_offset}, '\n');
+  printk("         table: ", table, '\n');
+  printk("          page: ", page, '\n');
+
+  if (directory[table] == 0) return 0;
+
+  uint32_t* page_table = reinterpret_cast<uint32_t*>(to_vma(reinterpret_cast<uint32_t>(directory[table])));
+  if (page_table[page] != 0) return 0;
+  page_table[page] = phys_page | 0x003;
+
+  uint32_t cr0;
+  asm volatile("mov %%cr0, %0" : "=r"(cr0));
+  asm volatile("mov %0, %%cr0" : : "r"(cr0));
+
+  return table * 4 * 1024 * 1024 + page * 4 * 1024 + phys_offset;
+}