[feat] support shm simplex inter-VM communication channel

[hky1999]

A simple simplex share memory based Inter-VM communication channel based on the publisher-subscriber model

• An IVCChannel is uniquely indexed by the publisher VM ID and key

• features

  • Each VM can register multiple IVC publisher channels
  • Each publisher channel can be subscribed by multiple subscribers
  • Subscribers need to use the publisher VM id and key to subscribe to the channel

• demos

  • Linux publisher
    • Currently, when you install axvisor.ko in Linux, it will register a publish channel by default (with its VM id + 0xdeadbeef as key).
    • refer to the axivc_publish.c for how to publish msg to channel from Linux.
  • Linux subscriber
    • Currently, axvisor.ko WILL NOT subscribe to any channel, in fact, it is done by a ioctl syscall from user process.
    • refer to the axivc_subscribe.c for how to subcribe to a channel with the given publisher id and channel key.
  • ArceOS publisher
    • refer to the demo app ivc_tester

• 🚧Work in progress

  • aarch64 only
  • When the publisher unpublishes a IVCChannel, it DOES NOT check if there is still any subscriber consuming it (It may cause a EPT Page fault).

See test-axvisor-ivc for details, it provides a example about ArceOS publishing msgs to IVCChannel, and a client process from Linux subscribing to it.

[hky1999]

• [feat] add EmuDeviceTIVCChannel axdevice_crates#35
• [feat] introcude EmulatedDeviceType with IVCChannel axvmconfig#2
• [feat] introcude IVC channel range allocator axdevice#9
• [fix] bug in read_from_guest_of axvm#21