id = 2860
title = "ps2 keyboard not work after boot and use libspice to connect it"
state = "opened"
created_at = "2025-03-13T11:30:45.533Z"
closed_at = "n/a"
labels = ["spice"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/2860"
host-os = "centos8"
host-arch = "x86"
qemu-version = "n/a"
guest-os = "windows"
guest-arch = "x86"
description = """When I start almost 10 qemu virtual machines, there will always be one or two that have the ps2 keyboard not work well after booted.But I use mstsc to connect to the desktop, the keyboard works fine. But when reboot or migrate it well recovery."""
reproduce = """1.Asynchronously start 40 qemu virtual machines, each with 4 cores and 4 threads

2.there will always be one or two that have the ps2 keyboard not work well.

4.And when i gdb debug it, i found i hang at the func "prepare_mmio_access"

5.reboot or migrate it well recovery"""
additional = """the gdb debug as fllow:

gdb attach $pid 

gdb>b kbd_push_key      //spice input

gdb>b kbd_read_data

gdb>b ps2_keyboard_event

gdb>c

After continue, the code run on ps2_keyboard_event,but no work to "kbd_read_data".This Proves that the keyboard input has been added to the queue, but has not been read from the queue.

gdb> thread 4   //switch to thread "CPU 0/KVM"

gdb> bt

![image](/uploads/82527d2b382cacd2d4e40793d78d3e59/image.png)

I guess there is no event to notify the device to read after writing to the queue, or is it deadlocked? I'm not sure"""