[Xen-devel] Re: [Xen-users] External modem in domU

[John S Little <JSLittl@xxxxxxxxxxxxx>]

Ryan <hap9@xxxxxxxxxxxxxx> wrote on 02/21/2006 03:59:31 PM:

> On Tue, 2006-02-21 at 14:32 -0500, John S Little wrote:
> > Ryan <hap9@xxxxxxxxxxxxxx> wrote on 02/21/2006 02:23:39 PM:
> > 
> > > On Mon, 2006-02-20 at 14:23 -0500, John S Little wrote:
> > > > Hi all
> > > > 
> > > > Is it possible to use an external modem in a domU?  I read several 

> > posts, 
> > > > most notably the one below,  but didn't see anything recently.  If 

> > it's 
> > > > possible is the an example config somewhere?
> > > > 
> > > > 
> > 
http://lists.xensource.com/archives/html/xen-users/2005-08/msg00602.html1
> > > > 
> > > > 
> > > > Regards,
> > > > 
> > > > John Little
> > > > Hendricks Regional Health IS Department
> > > > 317-718-4752
> > > > jslittl@xxxxxxxxxxxxx
> > > > http://www.hendrickshospital.org
> > > > 
> > > 
> > > John,
> > > 
> > > If your serial ports are on a separate PCI card, you could use the
> > > functionality in Xen 2.0.x or in the xen-unstable tree to put that 
PCI
> > > card in your domU. There's some documentation for this in the Xen 
user
> > > manual now. This would probably be the easiest solution.
> > > 
> > > If you have built-in serial ports... it will probably be harder. 
You'll
> > > need to manually specify to Xen which i/o ports and which IRQ to 
give to
> > > the domU. Xen 3.0.1 and later (maybe 3.0.0, I'd have to double-check
> > > when the functionality was introduced) have support for sharing i/o
> > > ports and interrupts, however there is no xend component for setting 
up
> > > the interrupt sharing (see tools/python/xen/xend/server/iopif.py for 
the
> > > i/o ports part). If you're interested in experimenting and building 
your
> > > own tools, I have some experimental code for adding the interrupt
> > > configuration support to xend that I may be able to post on the 
list.
> > > 
> > > Ryan
> > > 
> > 
> > Hello Ryan,
> > 
> > I am using 3.0.1 on an x86_64 sun box.   The serial ports are built 
in. I 
> > would be interested in having a try at your experimental code for 
this. 
> > Thinking about the pci part of that though would it be just as easy to 
get 
> > an internal non-winmodem (if such exists-it's been a long time since 
if 
> > messed with a modem)?
> > 
> > Regards,
> > 
> > John Little
> > 
> 
> Yes, an internal modem would work with the PCI deriver domain support
> (even a "winmodem" might work if it had the appropriate drivers for your
> OS - some drivers exist for winmodems under linux). Look in the Xen user
> manual for the section on "Driver Domain Configuration" for help with
> the PCI setup. The code for this is not in 3.0.1, you'd need to get the
> latest from xen-unstable to make this work.
> 
> The attached patch (which should apply to xen-unstable and 3.0.1) adds
> support for configuring interrupts in xend (and fixes what looks like a
> minor bug in xend's support for i/o ports). With this patch, add
> something like the following to your domU config file to get the serial
> port in domU:
> 
> irq = [4]
> ioports = ['3f8-3ff']
> 
> You'll also need to compile in the serial port drivers in your domU
> (under "Device Drivers" -> "Character Devices"). These may be disabled
> by an option under the "XEN" menu so check there first.
> 
> Let me know how this patch works for you.
> 
> I'm curious, are others interested in driver domains for legacy devices
> (like serial ports, ps/2 ports, ISA cards)? What other kinds of
> devices/buses need to be supported with driver domains?
> 
> Ryan
> [attachment "irqif.patch" deleted by John S Little/Hendricks] 

Ryan,

Just to make sure I do this right.  I have two paths that show the 
iopif.py file.  Should I apply the patch in both places or just the 
tools/python/xen/xend/server/iopif.py and recompile the kernel?

The paths that I show are:
/root/xen-3.0.1/tools/python/build/lib.linux-x86_64-2.3/xen/xend/server/iopif.py
/root/xen-3.0.1/tools/python/xen/xend/server/iopif.py

Or do I put it in the patches/folder and recompile?

BTW serial ports are enabled in the kernel as a module.  They  are also 
enabled in Xen via XEN_PHYSDEV_ACCESS which is automatic when  [*] 
Privileged Guest (domain 0) is selected.  (At least that's the way I 
understand it).  Serial port irq sharing is not enabled.  Do I need to 
enable that?

Thanks,
John

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