# Xen paravirtualisation guest support

## Kugar

Hello, 

I am trying to configure kernel for a gentoo guest in XEN environment. The problem is : my XEN Dom0 machine only supports 32 bits and I am unable to get the Xen guest support in kernel.

When I disable 64bits support, I looses the specific Xen guest support and I don't find any solution to get the option back.

How can I get this option back ?

Informations : I am trying this on a fresh gentoo install, the kernel is 3.10.32-gentoo and the Dom0 is an ubuntu server.

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## Atom2

If you don't use X86_64 but rather X86_32 you also have to enable the Intel Physical Address Extensions (X86_PAE) for the processor to be able to run as a guest under XEN. You can find the required option under 

```
Processor type and features

   High Memory Support

      64GB
```

If 64GB (and not '4GB' or 'off') is selected you should be able to to also enable Xen guest support.

Atom2

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## Kugar

That's what I have already read in this forum but I have tried to activate these option and I still can't see Xen guest support  :Sad: 

```
(chroot) dom0 kernels # grep X86_32 kernel-config-x86-3.10.32-gentoo

CONFIG_X86_32=y

CONFIG_X86_32_SMP=y

CONFIG_X86_32_LAZY_GS=y

# CONFIG_X86_32_IRIS is not set

(chroot) dom0 kernels # grep PAE kernel-config-x86-3.10.32-gentoo

CONFIG_X86_PAE=y

(chroot) dom0 kernels # grep XEN kernel-config-x86-3.10.32-gentoo

# CONFIG_XEN_PRIVILEGED_GUEST is not set

CONFIG_NETXEN_NIC=m
```

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## Atom2

 *Kugar wrote:*   

> 
> 
> ```
> (chroot) dom0 kernels # grep XEN kernel-config-x86-3.10.32-gentoo
> 
> ...

 

You are mixing two different things here: CONFIG_XEN_PRIVILEGED_GUEST is only required for your dom0 (that's the privileged guest) - and that's obviously already provided for by your Ubuntu system. If I understand you correctly, you only want to run gentoo as a domU, so there's no need for that option.

However, if your output of grep for XEN is complete, then there's still a lot missing. First of all you need to enable the option CONFIG_XEN and that should provide you with a number of other XEN related options to choose from.

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## Kugar

EDIT : Ok, I have found my mistake, the processor family was not good, I selected an other family and now I have Xen kernel options ands everything works fine !

First, thank you for trying to help me.

I know about CONFIG_XEN_PRIVILEGED_GUEST, my command was just to show that I don't have any other XEN option in my config file. The problem is that I never get the CONFIG_XEN option available ...

I've already configured that but in a hosted server that is 64bits compatible and I had no problem running gentoo DomU on Debian Dom0 for example.

You can find there : http://kugar.free.fr/gentoo/ a sreenshot of my kernel config in linux guest support menu and my kernel config file if you want to see it.

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## jlpoole

 *Kugar wrote:*   

> 
> 
> You can find there : http://kugar.free.fr/gentoo/ a sreenshot of my kernel config in linux guest support menu and my kernel config file if you want to see it.

 

The link above no longer resolves; do you have an alternative link or location?

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## Kugar

The problem is solved, I finally found the right options combination to be able to set guest options.

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