Subject: Xen/amd64 status [Re: CVS commit: [bouyer-xenamd64] src/sys/arch]
To: Adam Hamsik <>
From: Manuel Bouyer <>
List: port-xen
Date: 10/22/2007 00:11:08
On Sun, Oct 21, 2007 at 06:42:56PM +0200, Adam Hamsik wrote:
> [...]
> >The xenamd64 kernel is now good enough to complete a sysinst  
> >install from
> >xennet to xbd.
> >
> Good work, Manuel I'm going to test this kernel.

thanks ! :)

> Can you upload kernel image somewhere ?

OK, I'll also take the opportunity to post a status update.

With the code currently in-tree, the system is stable enough to
install from sysinst over the network to a xbd, but it occasinally
panics on a make -j4 dependall kernel build: it gets a page fault trying to
read a PTE entry (although with the last code, I got only one panic for
a full kernel build) So there's still some bug/race condition in the pmap code.
There's also a few things that don't work as it should:
- 'systat vm' complains about "The alternate system clock has died". I don't
  remember what this means exactly, but I suspect it could be because the
  symbol table is not loaded. This may be fixed with a newer Xen, or
  using the xentools from the NetBSD package (I'm currently using a
  fedora 7 as dom0).
- all CPU time is accounted to system or interrupt, there's no user time
  accounted. Probably missing assembly stubs at some places.
- It would be nice if someone could test it on a box with more than
  4GB ram :)
- I'm not sure there's no delayed/missed interrupts. Also linux has code to
  detect interrupt reentrancy and clean up the stack if this happens,
  to avoid stack overflow. We should probably try to do something similar.

Short term, the branch should be updated to a HEAD, new that the yamt-x86pmap
branch has been merged. after that, and once the domU bugs are tested,
the branch can be merged to HEAD, and I'll start working on dom0

Kernels from current sources are available from
Note that if you use netbsd-INSTALL_XEN3_DOMU.gz to install a domU, you'll
have to create the xbd devices yourself as there's no xen devices in
the amd64 MAKEDEV yet (exept the one in the ramdisk in this kernel).
To build from sources, checkout a full current source tree, and run
cvs update -dPA -r bouyer-xenamd64
in src/sys

Manuel Bouyer <>
     NetBSD: 26 ans d'experience feront toujours la difference