# xen dom0 kernel [SOLVED]

## umka69

Hi. I have small problem with kernel. I emerged xen and xen-tools than I tried to add xen to my kernel. But... I have this...

```

# cat /usr/src/linux-3.8.13-gentoo/.config | grep XEN

NOTHING!!!

```

How to fix it? Why is it going on?Last edited by umka69 on Sat Aug 17, 2013 5:03 pm; edited 2 times in total

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## TomWij

How did you add xen to the kernel?

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## umka69

I am going to do it, but there aren't any xen options in kernel sources. How can I get gentoo-sources with xen?

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## TomWij

You need to search for XEN with the / key and then see what it depends on, probably one of its dependencies hasn't been enabled.

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## umka69

Can you explain about /? How can I search for dependences? I don't understand.

If it matters... I already add use flag xen and update my system.

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## TomWij

 *umka69 wrote:*   

> Can you explain about /? How can I search for dependences? I don't understand.

 

If you press that key in the menuconfig, it will allow you type XEN and then you can hit enter and see search results (scroll with the page down key). Then for the XEN config variables you will see information about what it depends on. So, let's say it lists that it wants A && B && !C || D && !F then that means that it will become available if you have 1) A enabled, B enabled and C disabled or when you have 2) D enabled and F disabled. So, then you could for example pick option 2 and then you need to go ensure that D is enabled and F is disabled in your kernel; after that, you will be able to enable the option.

So, for XEN on x86 on amd64 you will find that it needs PARAVIRT && (X86_64 || (X86_32 && X86_PAE && !X86_VISWS)) && X86_TSC. Thus, as a start enable PARAVIRT and X86_TSC, then only if you plan to run a 32-bit kernel you will also need to ensure that X86_PAE is enabled and X86_VISWS is disabled.

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## umka69

Ok. I acted this way. / shows, for example, this:

```

  │ Symbol: XEN_COMPAT_XENFS [=n]                                                                                      

  │ Type  : boolean                                                                                                                   

  │ Prompt: Create compatibility mount point /proc/xen                                                                 

  │   Defined at drivers/xen/Kconfig:99                                                                                

  │   Depends on: XEN [=n] && XENFS [=n]                                                                              

  │   Location:                                                                                                        

  │ (1) -> Device Drivers                                                                                          

  │       -> Xen driver support                                                                                       

  │         -> Xen filesystem (XENFS [=n]

```

But there isn't any Xen driver support in Device Drivers...   :Shocked: 

This is the problem.

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## TomWij

Because of

 *Quote:*   

> Depends on: XEN [=n] && XENFS [=n]

 

so you need to enable XEN and XENFS first before you can enable XEN_COMPAT_XENFS.

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## umka69

How can I do this? Can I just add [code below] to .config or is it located in menuconfig? 

```
 /usr/src/linux/.config

...

CONFIG_XEN=y

CONFIG_XENFS=y

...

```

Last edited by umka69 on Sat Aug 17, 2013 4:46 pm; edited 1 time in total

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## TomWij

 *umka69 wrote:*   

> How can I do this?

 

As explained above.

 *umka69 wrote:*   

> Can I just add these to .config or is it located in menuconfig?

 

The .config explicitly states not to change it, they are located in the menuconfig.

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## umka69

Thank you a lot!  I've got it!  :Very Happy: 

My mistake was not enough knowledges about menuconfig.  :Smile: 

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