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 ?

score 1 · Answer 1 · answered Jul 07 '22 at 10:56

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.

answered Jul 07 '22 at 10:56

Peter Maydell

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does virtio-serial devices bypass MMIO for write operations? – Animesh Kumar Sinha Jul 20 '22 at 11:12
It cannot do so entirely, but it is designed to minimise the number of MMIO device writes the guest has to do. Most data communication happens via an in-guest-memory ring buffer structure that is updated by both the guest and the emulated-device side. – Peter Maydell Jul 20 '22 at 12:27
can ivshmem be used for sending data from Guest to Host while ensuring performance ? – Animesh Kumar Sinha Jul 22 '22 at 05:53

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

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