Support receiving signals when connecting to RDMA

[YWHyuk]

This patch make signal works during the connection of RDMA.
It is implemented by moving "start_io_router" forward.

"start_io_router" function does

• make RDMA connection
• make io_router thread (It is just loop of receiving IO event)

Those are quite position independent. So moving it forward will not make problems

Anyway, we can terminate the qemu by SIGINT(Ctrl+ c)🙌!
Thank you!

[ememos]

I tested the revised version you suggested.
As a result of the test, an abnormal symptom of frequent soft lockup occurred.
When I revert to the original version, the soft lockup phenomenon disappears.
In my test, I made a total of 20 vCPUs on two nodes, and I booted guest os.
I tested memcpy benchmark.

The following is a screenshot of guest booting.

[YWHyuk]

@ememos

I tested the revised version you suggested.
As a result of the test, an abnormal symptom of frequent soft lockup occurred.
When I revert to the original version, the soft lockup phenomenon disappears.
In my test, I made a total of 20 vCPUs on two nodes, and I booted guest os.
I tested memcpy benchmark.

Hmm.... It is strange😭. I tested it just a minute ago. But it works well.. My result is this.

• Left top terminal: Guest OS's top
• Left bottom terminal: memcpy benchmark on the Guest OS(By ssh)
• Right terminal: the other node log

My environment is 8 vCPUS. At the upper left terminal, I can see that all vCPU is utilized..

I don't know what's the reason for soft-lockup.