[Qemu-devel] Multiple Port Support for virtio-console

[Amit Shah]

Hello all,

Here is a new iteration of the patch series that implements a
transport for guest and host communications.

I've tested for compatibility (old qemu & new kernel, new qemu & old
kernel, new qemu & new kernel) and it all works fine*. Migration works
with the patch Juan just posted.

There are a few items on my todo list but this works well.

New since last send:
- migrate per-port buffers that are queued up
- in-qemu api for open/close/read/write of ports.
  - the read() is a callback that's invoked when complete data
    corresponding to one write() request on the guest is available.
- removed comments from virtio_console.c that are no longer relevant.
- address review comments by Juan

TODO:
- Convert all config writes to little endian in qemu / convert from
  little endian to host endian in guest
- Address a few FIXMEs spread in the code
- Introduce a watermark to stop a rogue host process flooding guest
  with data

Conditions:
* Heavy IO on an hvc port and a non-hvc port causes memory corruption
  each time, same place. It could be realted to locking but I doubt
  that. This still has to be sorted out

Please review.
        Amit