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Re: [Xen-users] How to Export COM port to guest domain

To: <xen-users@xxxxxxxxxxxxxxxxxxx>, "Jefferson E. Noxon" <jeff@xxxxxxxxxxxxxx>
Subject: Re: [Xen-users] How to Export COM port to guest domain
From: "Nick Couchman" <Nick.Couchman@xxxxxxxxx>
Date: Thu, 15 May 2008 14:53:13 -0600
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I don't think it's quite this hard.  For a Linux domU, here are the lines I add to export the com port to my domU:

irq=[ 4 ]

ioports=[ "3f8-3ff" ]

For the Windows HVM domU end of things, it's been a while since I did it, but I'm pretty sure just adding the following got me the necessary access to the com port:


My servers don't support VT-d and I'm not running Xen 3.2.  As far as USB devices go, I'm not sure, but my example domU files have things like "usbdevice='xxx'" - I'm not sure what types of USB devices you can push through, maybe just the default mouse and tablet support.


>>> On Thu, May 15, 2008 at 12:59 PM, "Jefferson E. Noxon" <jeff@xxxxxxxxxxxxxx> wrote:

I've run into the same problem, except that I need to provide serial
ports to a fully virtualized Windows guest.

This is my understanding:

You need Xen 3.2+, VT-d capable hardware, and PCI passthrough, and
probably a PCI-e serial adapter or a PCI-e USB adapter with a USB to
Serial dongle.  VT-d won't let you pass through a legacy (non-Express)
PCI device without passing all of your other legacy PCI devices behind
the same bridge.

It's a shame that it isn't possible to pass USB or Serial devices
without VT-d.

I plan to get a PCI-e USB controller and a VT-d capable motherboard soon.

I hope someone proves me wrong!

Johnson, Tony M wrote:
> Greetings,
> Using Xen 3.1 and Fedora 7, is it possible to export the serial
> interface such that I can access
> external devices on COM1 or COM2?
> I am uncertain if PCI pass-thru is needed or if there's nothing to
> configure for this to work in
> a fully virtualized Linux guest.
> Any help would be greatly appreciated.
> Regards,
> Tony Johnson
> ------------------------------------------------------------------------
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users

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