# Kernel 3.0 and Xen [new features]

## pablolibo

Hello everybody,

I am currently having a problem with gentoo-sources 3.0 , I am not found the new features on the combatibilidad between xen and kernel 3.0 . Does anyone know how enable DOM0 (xen) in new kernel 3.0?

Any idea?

Thanks in advances

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## fbcyborg

Hi!

As far as I know you can do as usual. Enable the following:

```
Processor type and features  --->

   [*] Paravirtualized guest support  --->

      [*]   Xen guest support
```

then:

```
Device Drivers  --->

   Xen driver support  --->

      [*] Xen memory balloon driver (NEW)

      [*]   Scrub pages before returning them to system (NEW)

      <*> Xen /dev/xen/evtchn device (NEW)

      [*] Backend driver support (NEW)

      <*> Xen filesystem (NEW)

      [*]   Create compatibility mount point /proc/xen (NEW)

      [*] Create xen entries under /sys/hypervisor (NEW)

      <M> userspace grant access device driver (NEW)

      <M> User-space grant reference allocator driver (NEW)

      <M> xen platform pci device driver (NEW)

   [*] Network device support  --->

      < >   Xen network device frontend driver

      <*>   Xen backend network device
```

Try and let me know please.

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## fbcyborg

Also the following is necessary:

```
Device Drivers  --->

   [*] Block devices  --->

      <*>   Xen virtual block device support

      <*>   Xen block-device backend driver

Networking support  --->

   Networking options  --->

      <M> 802.1d Ethernet Bridging
```

I tried to start a VM and I had no one problem with this configuration.

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## maurs

 *fbcyborg wrote:*   

> Also the following is necessary:
> 
> ```
> Device Drivers  --->
> 
> ...

 

thank you for posting this kernel configuration

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## themightychris

What changes are necessary for compiling a domU kernel? I haven't been able to disable the dom0 or privileged domain config flags or find any up to date documentation online. 

I tried using menuconfig to disable the backend drivers but my domU boot hangs at "XENBUS: Waiting for devices to initialise"

here's the relevant bits of my .config:

```
linux-3.0.6-gentoo-domU # grep XEN .config

CONFIG_XEN=y

CONFIG_XEN_DOM0=y

CONFIG_XEN_PRIVILEGED_GUEST=y

CONFIG_XEN_PVHVM=y

CONFIG_XEN_MAX_DOMAIN_MEMORY=128

CONFIG_XEN_SAVE_RESTORE=y

# CONFIG_XEN_DEBUG_FS is not set

# CONFIG_XEN_DEBUG is not set

CONFIG_PCI_XEN=y

CONFIG_XEN_PCIDEV_FRONTEND=y

CONFIG_XEN_BLKDEV_FRONTEND=y

# CONFIG_NETXEN_NIC is not set

CONFIG_XEN_NETDEV_FRONTEND=y

CONFIG_INPUT_XEN_KBDDEV_FRONTEND=y

CONFIG_HVC_XEN=y

# CONFIG_XEN_WDT is not set

CONFIG_XEN_FBDEV_FRONTEND=y

CONFIG_XEN_BALLOON=y

CONFIG_XEN_SCRUB_PAGES=y

CONFIG_XEN_DEV_EVTCHN=y

# CONFIG_XEN_BACKEND is not set

CONFIG_XENFS=y

CONFIG_XEN_COMPAT_XENFS=y

CONFIG_XEN_SYS_HYPERVISOR=y

CONFIG_XEN_XENBUS_FRONTEND=y

CONFIG_XEN_GNTDEV=m

CONFIG_XEN_GRANT_DEV_ALLOC=m

CONFIG_XEN_PLATFORM_PCI=m

CONFIG_SWIOTLB_XEN=y
```

Am I missing something?

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## fbcyborg

 *themightychris wrote:*   

> Am I missing something?

 

No, I don't think so. 

This is mine, and it works:

```
CONFIG_XEN=y

CONFIG_XEN_DOM0=y

CONFIG_XEN_PRIVILEGED_GUEST=y

CONFIG_XEN_PVHVM=y

CONFIG_XEN_MAX_DOMAIN_MEMORY=128

CONFIG_XEN_SAVE_RESTORE=y

# CONFIG_XEN_DEBUG_FS is not set

# CONFIG_XEN_DEBUG is not set

CONFIG_PCI_XEN=y

CONFIG_XEN_PCIDEV_FRONTEND=y

CONFIG_XEN_BLKDEV_FRONTEND=y

# CONFIG_NETXEN_NIC is not set

CONFIG_XEN_NETDEV_FRONTEND=y

CONFIG_INPUT_XEN_KBDDEV_FRONTEND=y

CONFIG_HVC_XEN=y

# CONFIG_XEN_WDT is not set

CONFIG_XEN_FBDEV_FRONTEND=y

CONFIG_XEN_BALLOON=y

CONFIG_XEN_SCRUB_PAGES=y

# CONFIG_XEN_DEV_EVTCHN is not set

# CONFIG_XEN_BACKEND is not set

# CONFIG_XENFS is not set

# CONFIG_XEN_SYS_HYPERVISOR is not set

CONFIG_XEN_XENBUS_FRONTEND=y

# CONFIG_XEN_GNTDEV is not set

CONFIG_XEN_GRANT_DEV_ALLOC=m

CONFIG_XEN_PLATFORM_PCI=m

CONFIG_SWIOTLB_XEN=y
```

Yours looks very similar to mine.

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## richard.scott

Do you have to change or add anything to grub to get the hypervisor/dom0 features?

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## fbcyborg

Yes, you may look for an example here.

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## richard.scott

thanks, I'll take a look.

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