Re: [Xen-users] PV Drivers in Linux HVM DomU?

["Emre Erenoglu" <erenoglu@xxxxxxxxx>]

I think I'm starting to get it. I have to do both steps. Now I'm trying to download the sources for Xen and XenLinux from my Ubuntu repositories.

However, I can't understand the difference between "Xen Sources" and "XenLinux Sources" mentioned in the README. What are they?

Xen Sources = Hypervisor source code?
XenLinux sources = xen dom0 kernel?

Can anybody comment?

Emre

On Nov 26, 2007 6:48 PM, Emre Erenoglu < erenoglu@xxxxxxxxx> wrote:

Hi Again,

I'm now running my domU as a HVM domU. I also downloaded the source of "unmodified drivers" from the xensource 3.1 repository.

However, I can't compile it, do you have an idea why? I'm attaching the output below (note that kernel itself compiles just fine). Some of t

voyager linux-2.6 # pwd
/d/xen/xen-3.1-testing.hg/unmodified_drivers/linux-2.6

voyager linux-2.6 # cat README
To build:

1. ./mkbuildtree
   NB. You can override paths to Xen sources and XenLinux sources via
       the XEN and XL environment variable.

2. make -C /path/to/kernel/source M=$PWD modules
   NB. The kernel sources here are your native kernel build tree, not
       the XenLinux sources referred to in step 1.

You get four modules, xen-platform-pci.ko, xenbus.ko, xen-vbd.ko, and
xen-vnif.ko.  Load xen-platform-pci first, then xenbus, and then
whichever of xen-vbd and xen-vnif you happen to need.

voyager linux-2.6 # make -C /usr/src/linux-2.6.18.8-86/ M=$PWD modules
make: `/usr/src/linux-2.6.18.8-86' entering directory
make[2]: *** Hedef `/d/xen/xen-3.1-testing.hg/unmodified_drivers/linux-2.6/balloon/balloon.o'  no rule to compile balloon.o, `/d/xen/xen-3.1-testing.hg/unmodified_drivers/linux-2.6/balloon/xen-balloon.o' is needed. stop.
make[1]: *** [/d/xen/xen-3.1-testing.hg/unmodified_drivers/linux-2.6/balloon] Error 2
make: *** [_module_/d/xen/xen- 3.1-testing.hg/unmodified_drivers/linux-2.6] Error 2
make: `/usr/src/linux-2.6.18.8-86' leaving directory
voyager linux-2.6 #

I translated some of the error messages from Turkish to English but I guess you'll get the point. What am I doing wrong? Should I first run the 1st step or not? As I'm in a HVM DomU, I don't see a reason to run the first step. If so, which sources shall I use for Xen, the sources in my dom0?

Didn't get it fully I guess...

Thanks a lot,

Emre

On Nov 22, 2007 3:35 PM, Pasi Kärkkäinen < pasik@xxxxxx> wrote:

On Thu, Nov 22, 2007 at 01:47:06PM +0100, Emre Erenoglu wrote:
> Hi,
>
> Is it possible to use HVM (full virtualization) for Linux guests but use PV
> drivers instead inside the DomU for extra performance?
>

Yes.

> What shall I do to be able to do it? Where can I download these drivers for
> several standard kernels? (HVM domU = standard distribution kernel,
> not-xen-aware)
>

You can download xen source tree and compile "unmodified drivers" from
there, or you can use the ones distributed with your distribution, if
available.

> Or, does the recent introduction of VMI into the linux kernel make this
> automatic for us? i.e. if I use any recent kernel, such as Ubuntu's
> 2.6.22-14-generic, will paravirtualized disk/network drivers be
> automatically activated?
>

VMI is VMware's interface to run paravirtual Linux on VMware. It doesn't
work or help at all with Xen.

If you're running paravirtual linux on xen, you already have paravirtualized
("full speed") drivers in use.

If you're using HVM domU on Xen, then you need to install Xen PV drivers on
domU.

-- Pasi

--

Emre Erenoglu
erenoglu@xxxxxxxxx

-- 
Emre Erenoglu
erenoglu@xxxxxxxxx
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