Possible ways to communicate between Guest to Host OS using Qemu?

Question

What other possible ways exists to send data from Guest OS to Host Machines ?

I have tried in Qemu:

(1)using vhost-vsock, but it lags in performance.

(2)MMIO callbacks, but it also lags in performance.

Is there any other mechanism by which we can send data from Guest to Host using Qemu ?

Answer 1

You could also try:

• TCP socket (via QEMU's emulated networking)
• sending via emulated serial port

though these are more "straightforward, easy to do without changing QEMU at all" rather than the necessarily most performant ways.

Broadly for performance you want something where the guest doesn't have to make a lot of MMIO register accesses to transfer a block of data, so anything virtio-based is probably worth looking at -- there are virtio-serial devices, for instance.