Improve arch-specific separation in API code.
diff --git a/src/api.c b/src/api.c
new file mode 100644
index 0000000..a105f6d
--- /dev/null
+++ b/src/api.c
@@ -0,0 +1,72 @@
+#include "api.h"
+
+#include "arch_api.h"
+#include "vm.h"
+
+struct vm secondary_vm[MAX_VMS];
+uint32_t secondary_vm_count;
+struct vm primary_vm;
+
+/**
+ * Returns the number of VMs configured to run.
+ */
+int32_t api_vm_get_count(void)
+{
+ return secondary_vm_count;
+}
+
+/**
+ * Returns the number of vcpus configured in the given VM.
+ */
+int32_t api_vcpu_get_count(uint32_t vm_idx)
+{
+ if (vm_idx >= secondary_vm_count)
+ return -1;
+
+ return secondary_vm[vm_idx].vcpu_count;
+}
+
+/**
+ * Runs the given vcpu of the given vm.
+ */
+int32_t api_vcpu_run(uint32_t vm_idx, uint32_t vcpu_idx, struct vcpu **next)
+{
+ struct vm *vm = secondary_vm + vm_idx;
+ struct vcpu *vcpu;
+
+ /* Only the primary VM can switch vcpus. */
+ if (cpu()->current->vm != &primary_vm)
+ return HF_VCPU_WAIT_FOR_INTERRUPT;
+
+ if (vm_idx >= secondary_vm_count)
+ return HF_VCPU_WAIT_FOR_INTERRUPT;
+
+ vcpu = vm->vcpus + vcpu_idx;
+ if (vcpu_idx >= vm->vcpu_count || !vcpu->is_on)
+ return HF_VCPU_WAIT_FOR_INTERRUPT;
+
+ arch_set_vm_mm(&vm->page_table);
+ *next = vcpu;
+
+ return HF_VCPU_YIELD;
+}
+
+/**
+ * Puts current vcpu in wait for interrupt mode, and returns to the primary
+ * vm.
+ */
+struct vcpu *api_wait_for_interrupt(void)
+{
+ struct vcpu *vcpu = &primary_vm.vcpus[cpu_index(cpu())];
+
+ /* Switch back to primary VM. */
+ arch_set_vm_mm(&primary_vm.page_table);
+
+ /*
+ * Inidicate to primary VM that this vcpu blocked waiting for an
+ * interrupt.
+ */
+ arch_regs_set_retval(&vcpu->regs, HF_VCPU_WAIT_FOR_INTERRUPT);
+
+ return vcpu;
+}