[ovirt-users] experimenting with host device passthrough in ovirt 3.6

[Jason Keltz]

Hi.

I'd like to experiment with host device passthrough in ovirt 3.6.
I have a temperature sensor that connects up to a serial port.
I've plugged the device into one of my virt hosts, and through 
/dev/ttyS1, I can read it.

# dmesg | grep ttyS1
[    1.140221] 00:04: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A

ls -l /sys/class/tty/ttyS1/device/driver reveals:

> total 0
> drwxr-xr-x. 2 root root    0 Nov  7 19:01 .
> drwxr-xr-x. 7 root root    0 Nov  7 19:01 ..
> lrwxrwxrwx. 1 root root    0 Nov  9 11:32 00:04 -> 
> ../../../../devices/pnp0/00:04
> lrwxrwxrwx. 1 root root    0 Nov  9 11:32 00:05 -> 
> ../../../../devices/pnp0/00:05
> --w-------. 1 root root 4096 Nov  9 11:32 bind
> --w-------. 1 root root 4096 Nov  7 19:01 uevent
> --w-------. 1 root root 4096 Nov  9 11:32 unbind

> # ls -al /sys/devices/pnp0/00\:04/
> total 0
> drwxr-xr-x.  4 root root    0 Nov  7 19:01 .
> drwxr-xr-x. 17 root root    0 Nov  7 19:01 ..
> lrwxrwxrwx.  1 root root    0 Nov  7 19:01 driver -> 
> ../../../bus/pnp/drivers/serial
> lrwxrwxrwx.  1 root root    0 Nov  9 11:34 firmware_node -> 
> ../../LNXSYSTM:00/device:00/PNP0A08:00/device:18/PNP0501:00
> -r--r--r--.  1 root root 4096 Nov  9 11:32 id
> -r--r--r--.  1 root root 4096 Nov  9 11:34 options
> drwxr-xr-x.  2 root root    0 Nov  7 19:01 power
> -rw-r--r--.  1 root root 4096 Nov  9 11:32 resources
> lrwxrwxrwx.  1 root root    0 Nov  7 19:01 subsystem -> ../../../bus/pnp
> drwxr-xr-x.  3 root root    0 Nov  7 19:01 tty
> -rw-r--r--.  1 root root 4096 Nov  7 19:01 uevent

I don't necessarily see this device listed in the host passtshrough.
In addition, since I'm able to connect to the serial device right now on 
the host, this would mean that I need to "blacklist" that device from 
the host so that when it boots, it doesn't load the driver?

Thanks for any help..

Jason.


-- 
Jason Keltz
Manager of Development
Department of Electrical Engineering and Computer Science
York University, Toronto, Canada
Tel: 416-736-2100 x. 33570
Fax: 416-736-5872