Re: Blank screen while booting xen

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Mon, Jan 11, 2016 at 11:15:43PM +0530, Harmandeep Kaur wrote:
> On Mon, Jan 11, 2016 at 11:00 PM, Konrad Rzeszutek Wilk
> <konrad.wilk@oracle.com> wrote:
> > On Mon, Jan 11, 2016 at 10:56:07PM +0530, Harmandeep Kaur wrote:
> >> On Mon, Jan 11, 2016 at 8:23 PM, Konrad Rzeszutek Wilk
> >> <konrad.wilk@oracle.com> wrote:
> >> > On Mon, Jan 11, 2016 at 12:57:27AM +0530, Harmandeep Kaur wrote:
> >> >> Hi,
> >> >>
> >> >> I tried to modify and compile some of Xen 4.7's code
> >> >> (cloned from git clone git://xenbits.xen.org/xen.git)
> >> >> and even with a very minor change (patch included at last)
> >> >> my xen failed to boot. It stucks at black blank screen after
> >> >> showing some xen logs.
> >> >
> >> > What is on your Linux command line? Do you have 'console=hvc0' ?
> >> my /etc/defaults/grub   http://paste2.org/BkOOOskh
> >> my /boot/grub/grub.cfg http://paste2.org/Ks49MZEh
> >> >
> >> >>
> >> >> By adding "vga=text-80x80,keep" to the grub before booting
> >> >> xen., infinite loop of text
> >> >> "(XEN) traps.c:3290: GPF (0000): ffff82d0801af4d5 -> ffff82d080240e5a"
> >> >> appears.
> >> >>
> >> >> I tried to compile and boot xen reverting the change, but
> >> >> same issue still exists.
> >> >>
> >> >> Also I tried to setup serial console but my output is garbled.
> >> >> More info on it here,
> >> >> http://lists.xenproject.org/archives/html/xen-devel/2015-12/msg02045.html
> >> >>
> >> >> I tried different software (cu, gtkterm), different baud rates,
> >> >> different serial-USB cable and stopping modemmanager,
> >> >> but no luck.
> >> >
> >> > How did you set the baudrate? I usually do 'screen /dev/ttyUSB0 115200 cs8'
> >> > ?
> >>
> >> I also tried the same with screen just without the cs8 keyword.
> >>
> >> >>
> >> >> I am using i3-6100 processor, if that info is needed.I will
> >> >> appreciate any help.
> >> >
> >> > dmesg | grep tty
> >>
> >> $ dmesg | grep tty
> >> [       0.000000] console [tty0] enabled
> >> [       4.537790] systemd[1]: Created slice system-getty.slice.
> >> [11542.458553] usb 1-4: pl2303 converter now attache
> >
> >
> > This is on your box with the USB dongle. I meant the other one.
> >
> here it is
> $ dmesg | grep tty
> [    0.000000] console [tty0] enabled
> [    0.786850] 00:04: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200)
> is a 16550A
> 
> > Maybe we should step back a bit. On the machine on which you
> > want to install Xen - does it work if you install say
> > Fedora Core 23 and after installing, you do 'yum install xen' ?
> > Can you boot with that? Then at least we will know whether an
> > packaged version of Xen works on your machine.
> 
> Yes, it works. I tried that with xen 4.5 on Ubuntu 15.10.
> Also, even my compiled version(4.7) used to run before
> my modification.

OK, so I would suggest you try again with the serial console but
using the non-modified hypervisor version. See if you can get the serial to work.

I would suggest you use screen as the other (cu, minicons) - I had issues
with them with USB devices. While screen also allows you to log them.

And do please check that you have 'console=com1 com1=115200,8n1 loglvl=all' on
your Xen command line. And on Linux 'console=hvc0'.

Once you have the serial working with the un-modified version I would
try the modified and see where it gets stuck.