Initial commit.
diff --git a/src/cpu.c b/src/cpu.c
new file mode 100644
index 0000000..85646c6
--- /dev/null
+++ b/src/cpu.c
@@ -0,0 +1,161 @@
+#include "cpu.h"
+
+#include "arch_cpu.h"
+#include "dlog.h"
+#include "std.h"
+#include "timer.h"
+#include "vm.h"
+
+struct new_old_vcpu {
+ struct vcpu *new;
+ struct vcpu *old;
+};
+
+void cpu_init(struct cpu *c)
+{
+ /* TODO: Assumes that c is zeroed out already. */
+ sl_init(&c->lock);
+ list_init(&c->ready_queue);
+ c->irq_disable_count = 1;
+}
+
+void cpu_irq_enable(struct cpu *c)
+{
+ c->irq_disable_count--;
+ if (!c->irq_disable_count)
+ arch_irq_enable();
+}
+
+void cpu_irq_disable(struct cpu *c)
+{
+ if (!c->irq_disable_count)
+ arch_irq_disable();
+ c->irq_disable_count++;
+}
+
+void cpu_on(struct cpu *c)
+{
+ sl_lock(&c->lock);
+ if (!c->cpu_on_count) {
+ /* The CPU is currently off, we need to turn it on. */
+ arch_cpu_on(c->id, c);
+ }
+ c->cpu_on_count++;
+ sl_unlock(&c->lock);
+}
+
+/*
+ * This must be called only from the same CPU.
+ */
+void cpu_off(struct cpu *c)
+{
+ bool on;
+
+ sl_lock(&c->lock);
+ c->cpu_on_count--;
+ on = c->cpu_on_count > 0;
+ sl_unlock(&c->lock);
+
+ if (!on)
+ arch_cpu_off();
+}
+
+void vcpu_ready(struct vcpu *v)
+{
+ struct cpu *c = v->cpu;
+
+ sl_lock(&c->lock);
+ if (!v->is_runnable) {
+ v->is_runnable = true;
+ list_append(&c->ready_queue, &v->links);
+ /* TODO: Send IPI to cpu if needed. */
+ }
+ sl_unlock(&c->lock);
+}
+
+void vcpu_unready(struct vcpu *v)
+{
+ struct cpu *c = v->cpu;
+
+ sl_lock(&c->lock);
+ if (v->is_runnable) {
+ v->is_runnable = false;
+ list_remove(&v->links);
+ }
+ sl_unlock(&c->lock);
+}
+
+#if 0
+static bool cpu_schedule_next(void *ctx)
+{
+ /* Indicate that a new vcpu should be chosen. */
+ return true;
+}
+#endif
+
+struct new_old_vcpu cpu_next_vcpu(void)
+{
+ struct cpu *c = cpu();
+ struct new_old_vcpu ret;
+ struct vcpu *next;
+ bool switch_mm;
+
+ /* TODO: Check if too soon. */
+
+ sl_lock(&c->lock);
+
+ ret.old = c->current;
+ if (list_empty(&c->ready_queue)) {
+ bool first = true;
+ c->current = NULL;
+ do {
+ sl_unlock(&c->lock);
+ /* TODO: Implement this. Enable irqs. */
+ if (first) {
+ dlog("CPU%d waiting for work...\n", c->id);
+ first = false;
+ }
+ sl_lock(&c->lock);
+ } while (list_empty(&c->ready_queue));
+ dlog("CPU%d found work!\n", c->id);
+ }
+
+ next = LIST_ELEM(c->ready_queue.next, struct vcpu, links);
+ if (next->links.next != &c->ready_queue) {
+ /* Move new vcpu to the end of ready queue. */
+ list_remove(&next->links);
+ list_append(&c->ready_queue, &next->links);
+ }
+
+ c->current = next;
+
+ if (next->interrupt) {
+ arch_regs_set_irq(&next->regs);
+ next->interrupt = false;
+ } else {
+ arch_regs_clear_irq(&next->regs);
+ }
+
+ switch_mm = !ret.old || ret.old->vm != next->vm;
+
+ sl_unlock(&c->lock);
+
+ ret.new = next;
+
+ if (switch_mm)
+ arch_set_vm_mm(&next->vm->page_table);
+
+ /* TODO: Only set this when there is a next thing to run. */
+ /* Set timer again. */
+ //timer_set(5 * 1000000, cpu_schedule_next, NULL);
+
+ return ret;
+}
+
+void vcpu_init(struct vcpu *vcpu, struct cpu *cpu, struct vm *vm)
+{
+ memset(vcpu, 0, sizeof(*vcpu));
+ vcpu->cpu = cpu;
+ vcpu->vm = vm;
+ /* TODO: Initialize vmid register. */
+}