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

[Hans Rakers <hans@xxxxxxxx>]

Nothing, as i already stated. I'm pretty sure Dom0 doesn't load anything 
serial-ish, and i've blacklisted the 8250/8250_pnp/serial_core modules 
on Dom0.
Grub.conf entry of Dom0 looks like this:

title CentOS (2.6.18-53.1.4.el5xen)
        root (hd0,0)
        kernel /xen.gz-2.6.18-53.1.4.el5 console=vga
        module /vmlinuz-2.6.18-53.1.4.el5xen 
root=/dev/VolGroup00/LogVol01 ro xencons=off
        module /initrd-2.6.18-53.1.4.el5xen.img


Kind regards,

Hans


Sadique Puthen wrote:
> What is the output of "dmesg | grep ttyS" in dom0?
>
> --Sadique
>
>
> Hans Rakers wrote:
> > Hello xen-users,
> >
> > Last days i've been pulling my hair on getting ttyS0 (COM1) to work in 
> > a HVM DomU. I want to use it for an external faxmodem for use with 
> > Hylafax. I've Googled myself crazy and have seen just about every page 
> > on this subject :)
> > My system is CentOS 5.1 with xen-3.0.3-41.el5. I've added xencons=off 
> > to grub.conf of DomU and i've added the following to 
> > /etc/modprobe.d/blacklist:
> > blacklist 8250
> > blacklist 8250_pnp
> > blacklist serial_core
> >
> > I can confirm that Dom0 does not claim the serial ports (no mention of 
> > it during boot, no modules loaded, xencons off)
> > My DomU also runs CentOS 5.1. I've added the following to its vm config:
> >
> > irq = [3, 4]
> > ioports = ["3f8-3ff", "2f8-2ff"]
> >
> > Syslog of the DomU mentions the loading of the 8250 module, but no 
> > resulting ports:
> > Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled
> >
> > /proc/ioports of the DomU also doesn't mention the mapped ioports:
> >
> > [...snip snip...]
> > 01f0-01f7 : ide0
> > 03c0-03df : vga+
> > 03f2-03f5 : floppy
> > 03f6-03f6 : ide0
> > 03f7-03f7 : floppy DIR
> > 0cf8-0cff : PCI conf1
> > [...snip snip...]
> >
> > Is this at all possible, or am i overlooking something stupid? Do 
> > 'ioports' and 'irq' work with fully virtualized VM's? I've read 
> > something earlier on this list at 
> > http://lists.xensource.com/archives/html/xen-users/2007-08/msg00838.html 
> > which states that it is impossible for HVMs to have direct access to 
> > hardware, which is why i ask, before spending another day on this :)
> > Thanks in advance,
> >
> > Hans Rakers
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
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