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Re: [Xen-users] Serial port access in HVM (fully virtualized) DomU

I'm having a similar problem with opensuse 10.2 and Xen 3.0.3.  I cannot get
Xen to release ttyS0 to Dom0, even with xencons=off or xencons=tty.  There
is no ttyS0 in dmesg and I get an invalid port message if I try to run
minicom on it.  However, if I reboot without the Xen kernel the port works
fine (shows up in dmesg and works in minicom).

Any ideas on how to troubleshoot this?



Trolle Selander wrote:
> This is a HVM DomU, so you need to use an emulated serial port backed by
> the
> physical port. There is no support for assigning physical serial port
> resources to "give" the serial port directly to the HVM DomU.
> Theoretically,
> this should be fairly easily doable even on IOMMU-less systems, but as far
> as I know. there's no code to do this yet for HVMs. Serial ports on a
> separate PCI card should be possible to using the PCI passthrough feature
> in
> recent versions of xen.
> However, the emulated device may work fine for you, with much less hassle.
> Just make sure that your serial ports _are_ available to Dom0 (that is,
> remove the blacklist entries), and then add serial=/dev/ttyS0 to your HVM
> domain config. There are some caveats with serial emulation currently -
> I'm
> working on improving this particular code right now, so if you run into
> any
> strangeness, I'll probably know what's going on and be able to help. :)

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