vmmcache: initial implementation

kernel-src/arch/x86-64/main.c

@@ -37,6 +37,7 @@
 #include <kernel/mouse.h>
 #include <kernel/tty.h>
 #include <kernel/pty.h>
+#include <kernel/vmmcache.h>
 
 static cpu_t bsp_cpu;
 
@@ -64,6 +65,9 @@ void kernel_entry() {
 	arch_apic_timerinit();
 	sched_init();
 	arch_smp_wakeup();
+
+	vmmcache_init();
+
 	vfs_init();
 	tmpfs_init();
 	devfs_init();

kernel-src/arch/x86-64/mmu.c

@@ -175,6 +175,13 @@ bool arch_mmu_iswritable(pagetableptr_t table, void *vaddr) {
 	return entry == NULL ? false : *entry & ARCH_MMU_FLAGS_WRITE;
 }
 
+#define ARCH_MMU_FLAGS_DIRTY (1 << 6)
+
+bool arch_mmu_isdirty(pagetableptr_t table, void *vaddr) {
+	uint64_t *entry = get_page(table, vaddr);
+	return entry == NULL ? false : *entry & ARCH_MMU_FLAGS_DIRTY;
+}
+
 void arch_mmu_switch(pagetableptr_t table) {
 	asm volatile("mov %%rax, %%cr3" : : "a"(table));
 }