Xen FAQ Booting: Difference between revisions

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== I have problems getting Xen or dom0 kernel to boot, how can I set up a serial console to log and troubleshoot the boot process? ==
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See the [[XenSerialConsole]] wiki page.
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== I am booting my new EFI-based system. I se "Loading ramdisk..." and then it stops ==
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Go into your BIOS and enable Legacy Booting (non-EFI). If it still doesn't work, upgrade the BIOS to its latest version.
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{{Needs_Refactor|This document may benefit being merged with relevant questions from [[XenFAQ2]] and other larger documents in [[:Category:FAQ]].}}
== Where do I find more Booting FAQs? ==

= Booting Xen =
See [[Xen_Common_Problems#Booting]]
== I get an error from Xen... (console output starting "(XEN)") ==

<pre><nowiki>
(XEN) Initial guest OS requires too much space
(XEN) (8MB is greater than 0MB limit)
</nowiki></pre>

Check that you are correctly specifying the <code><nowiki>dom0_mem</nowiki></code> command line option for starting Xen. Note that: <code><nowiki>dom0_mem=512M</nowiki></code> should work in recent versions while older versions such as 2.0.5 require the memory specification to be in kilobytes, e.g. <code><nowiki>dom0_mem=524288</nowiki></code>.

(Note: you need to leave some memory for Xen, so the above assumes you have more than 512M total in the system; if you still have problems, reduce the amount further).

== How do I hide a pci device from dom0? ==
In Xen 2.x, you can add the <code><nowiki>physdev_dom0_hide</nowiki></code> parameter (see [[XenBooting]] for more parameters) to hide one or more pci devices to Dom0, so you can affect them to domU.

Pci slots MUST be formatted like this:

* '''(nn:nn.n)'''
so

* <code><nowiki>(03:06.1)</nowiki></code> is correct
* <code><nowiki>(03:6.1)</nowiki></code> is NOT correct
You can get the pci bus address on a Linux system by using the lspci command (only the last bits are relevant):


<pre><nowiki>
lspci | grep Ethernet
0000:02:03.0 Ethernet controller: Intel Corp. 82546EB Gigabit Ethernet Controller (Copper) (rev 01)
0000:02:03.1 Ethernet controller: Intel Corp. 82546EB Gigabit Ethernet Controller (Copper) (rev 01)
</nowiki></pre>

Then:

* to hide the second network interface from dom0, you can then append <code><nowiki>physdev_dom0_hide=(02:03.1)</nowiki></code> to your <code><nowiki>kernel /boot/xen-2.0.gz</nowiki></code>.
* to hide multiple pci devices, simply concatenate all the pci slots address like this: <code><nowiki>physdev_dom0_hide=(02:03.0)(02:03.1)</nowiki></code>
If everything went ok, you should see the following lines after a reboot:


<pre><nowiki>
(XEN) Hiding PCI device 02:03.0 from DOM0
(XEN) Hiding PCI device 02:03.1 from DOM0
</nowiki></pre>

== Error about root device still mounted when it's not mounted, zombie domU that can't be killed, domU hangs under heavy I/O (e.g disk) access ==
This is an unresolved problem with Xen 3.0.

You may try to [http://lists.xensource.com/archives/html/xen-users/2006-03/msg00651.html pass nousb to dom0 kernel command line], or [http://lists.xensource.com/archives/html/xen-devel/2005-07/msg00436.html pass ignorebiostables], or try to [http://lists.xensource.com/archives/html/xen-devel/2005-07/msg00468.html disable software IRQ affinity for 1850/2850 systems].

* [http://lists.xensource.com/archives/html/xen-users/2006-02/msg00851.html Discussion in xen-users mailing list]


[[Category:Xen]]
[[Category:Xen]]

Latest revision as of 01:20, 8 October 2014

I have problems getting Xen or dom0 kernel to boot, how can I set up a serial console to log and troubleshoot the boot process?

See the XenSerialConsole wiki page.

I am booting my new EFI-based system. I se "Loading ramdisk..." and then it stops

Go into your BIOS and enable Legacy Booting (non-EFI). If it still doesn't work, upgrade the BIOS to its latest version.

Where do I find more Booting FAQs?

See Xen_Common_Problems#Booting