Re: [Xen-users] LPT configuration for the DomU

[sergey kostanbaev <sergey.kostanbaev@xxxxxxxxx>]

Thanks for the response.

On Wed, Aug 12, 2009 at 3:36 PM, James Harper <james.harper@xxxxxxxxxxxxxxxx> wrote:

> Hello everybody!
>
> Do you know how to pass physical LPT port to the DomU?
>
> I found some information about ioports=[''] but it seems it works only
if the
> port range is the same on the host and VM. My motheboard hasn't any
LPT so I
> use PCI board. Using such board lead to different IO range.
>
> 05:01.0 Communication controller: NetMos Technology PCI 9855 Multi-I/O
> Controller (rev 01)
>     Subsystem: LSI Logic / Symbios Logic Device 0014
>     Flags: medium devsel, IRQ 22
>     I/O ports at ec00 [size=8]
>     I/O ports at e880 [size=8]
>     I/O ports at e800 [size=8]
>     I/O ports at e480 [size=8]
>     I/O ports at e400 [size=8]
>     I/O ports at e080 [size=16]
>
> Does anybody know how to tell Xen using e080 host io for the 03bc vm
io

I guess you can't just pass the whole pci device through as you only
want a single port right?

Yep, the single port

The problem is that the i/o ports are only supposed to be touched by the
driver attached to the device, which isn't going to work (and indeed the
ports could be remapped etc as other devices are added and removed).

Can you use a USB to LPT adapter and just pass through the usb device
and make the DomU HVM?

Unfortunately, it's a problem because the software I'm using (an IC programmator) uses plain IO access via directio on windows host. So it won't work

Failing that, you should still be able to just pass through the i/o
ports 1:1 and tell the guest operating system (Linux?) to probe an lpt
port at the specified address (modinfo parport_pc to find the
parameters), which should work assuming the I/O ports are actually
compatible, although is certainly not recommended for reasons already
discussed.

I tried to configure LPT port on windows but it refuses to accept non-standard IO range (only 278, etc are acceptable). I'm digging the problem but without success

James

Some time ago I used vmware and there was a LPT emulaton via /dev/parport. To the guest it was like plain LPT and vmware used /dev/parport to communicate. 
Maybe Is there something like this? Communication via LPT is very simpe.
Can qemu help somehow to emulate guest LPT from the host?

I've been using Xen for few years and I don't want to switch to another software becasue of the problem.



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