Re: Using signals to communicate two Qemu processes

[Dor Laor <dlaor@redhat.com>]

Passera, Pablo R wrote:
> Hi all,
>         I am trying to communicate two VMs using a virtio driver. Once a data is moved to the driver I want to notify the other Qemu process that there is new data available in the buffer. I was thinking about using linux signals to synchronize both processes but when I register my SIGUSR1 handler in Qemu I am seeing an strange behavior. After starting the VM and Linux gets loaded, Qemu is receiving SIGUSR2 at a regular time period. Looking a little bit at the code I realize that signals are being used for other purposes in Qemu, however, SIGUSR1 is not used. Is it possible to use signals to synchronize these processes or should I think about using a different mechanism?
>
>   
SIGUSR2 is used as aio completion signal. You can use SIGUSR1 but you 
need to know what you're doing (some threads block signals).
Better fit would be a pipe.

The vcpu
> Thanks,
>
> Pablo Pássera
> Intel - Software Innovation Pathfinding Group
> Cordoba - Argentina
> Phone: +54 351 526 5611
>
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