[Qemu-devel] Multi Thread interrupt issue in Qemu system with KVM enabled

[chetandeep singh]

Hi All,

 I have been running Qemu for a while on simpler processes and really
appreciate all work that goes into this and would really appreciate your
help for an issue that I am facing.

I am using Qemu for some SDK Development/testing. SDK is a multi threaded
process where one thread is waiting for an interrupts from driver while
others are doing SDK execution.

I am using Ubuntu as Guest OS.

At one point in SDK execution, the main executing threads going in sleep
mode with FUTEX as times wait of 2 minutes wall clock time as one of the
conditions, other being arrival of interrupt from driver being looked out
by thread 2.

In this system, first suspicion was interrupt was not coming, while after
debug, it seems that interrupt is reaching the drivers. but due to main
thread 1 not yielding control to the thread 2, it goes undetected. As a
further proof, if I attach the GDB to the running SDK process and deattach
the GDB without any debug , SDK starts to execute further with arrival of
the Interrupt. Attaching the SDK seems to give time to threads.

would really appreciate any feedback on problem on what I can change in
setup to resolve this.

Qemu Version 2.0.2
Qemu-KVM Version : 0.12.1.2
I see kvm enabled in "info kvm" in qemu control window.
I am passing -cpu host -smp 4 to the Qemu x86 executable while running
ubuntu.

Thanks in advance.

Regards
Chetan