KVM virtualization with Qemu
Orion Electric Age
  2018-12-16 15:34:14 2018-12-16 15:34    

Qemu Threads

  • main thread: main_loop()/vl.c, main_loop_wait()/main-loop.c
    • Waits for file descriptors to become readable or writable. File descriptors play a critical role because files, sockets, pipes, and various other resources are all file descriptors. File descriptors can be added using qemu_set_fd_handler().
    • Runs expired timers. Timers can be added using qemu_mod_timer().
    • Runs bottom-halves (BHs), which are like timers that expire immediately. BHs are used to avoid reentrancy and overflowing the call stack. BHs can be added using qemu_bh_schedule().
  • io thread: iothread_run()
  • vcpu thread: qemu_kvm_cpu_thread_fn()

KVM and Qemu Interaction Diagram

  • KVM and Qemu Interaction Diagram
    KVM and Qemu interaction diagram

GuestOS, KVM and Qemu Iteraction Diagram: virtio-net

  • GuestOS, KVM and Qemu Iteraction Diagram: virtio-net
    GuestOS, KVM and Qemu Iteraction Diagram: virtio-net

Reference