Moin *, this is about combining SKAS & XEN without having any clue. If you are only interested in the details, go here:
<http://nils.toedtmann.net/stuff/xen-skas.txt> It does not really work, but almost. Maybe it's only a small last step to produce a functional SKAS-on-XEN-patch. Maybe someone could complete it? ###### I run several UMLs, and know i started playing with XEN. What is needed for testing and migration is a linux kernel which can act as a UML host (SKAS & sysemu patch) _and_ as a XEN host (XEN patch, configured for a "XEN domain 0"). So I patched a linuxtree with both and tried to understand why it would not work. Spending some time on the trial-and- error-method i came to the hypothesis (as i have NO F*CKING CLUE WHAT THE HELL I'M DOING HERE, i should say: wild guess) that i had to re-apply the SKAS-patches for arch/i386/* and include/asm-i386/* to arch/xen/i386/* and include/asm-xen/\ /asm-i386/*, too. Surprisingly that worked - more or less: The patches apply (with offsets, but no rejects), the host- kernel (XEN domain 0) builds, boots and runs. On that host- kernel, most applications run fine (firefox and some gnome- applets got unstable, but that seems to happen without SKAS, too). Indeed: now i can boot the same system image as a UML guest or as a XEN guest ("unprivileged domains"), and UML recog- nizes SKAS, /proc/mm & sysemu! Unfortunately, within my FC3 UMLs some binaries now crash :-( While sysV startup (including network, cron, syslog, sshd), bash, find, host, ping, ... all work fine, others like /bin/rpm or /bin/ls segfault. /usr/bin/vim also segfaults, but when it runs within strace, it works (WTF?). I could not produce such segfaults within a debian (woody) UML, yet. Example segfault (FC3, /bin/ls): <http://nils.toedtmann.net/stuff/ls-strace.txt> All segfaults i looked at end with set_thread_area(...) = -1 ENOSYS (Function not implemented) modify_ldt(...) = 0 --- SIGSEGV (Segmentation fault) @ 0 (0) --- The "set_thread_area(...) = -1 ENOSYS" is normal (or?), since there are no TLS libs any more, so it comes down to "modify_ldt". Maybe it's not coincidence that one of the kernel files i patched was arch/xen/i386/kernel/ldt.c ...? (ooops, yet another wild guess) When the host runs a non-SKAS XEN kernel, the segfaults in- side the UMLs disappear (but performance disappears, too). So it seems that this task cannot be accomplished without some knowledge ... anybody? /nils. ps: Booting a FC3 image as UML ... $ /home/uml/boot/linux-2.6.9-bb4-terminal-cleanup-nils9 umid=FC3test mem=128M \ con=null con0=null,fd:1 con1=fd:0,fd:1 eth0=tuntap,tap0,FE:FD:00:DE:AD:09 \ ubda=/home/uml/ubd/FC3-rootfs.ext3 ubdb=/home/uml/ubd/swap ... translates to this config file /etc/xen/FC3test.xm kernel = "/boot/vmlinuz-2.6.10-xen-2.0.4-domU-nils.2" name = "FC3test" memory = 128 nics = 1 vif = [ 'mac=FE:FD:00:DE:AD:09, bridge=xen-br0' ] disk = [ 'file:/home/uml/ubd/FC3-rootfs.ext3,hda1,w', 'file:/home/uml/ubd/swap,hda2,w' ] root = "/dev/hda1 ro" ... and this XEN domain startup command: # xm create -c FC3test.xm You only have to switch the guest's fstab from ubd* to hd*. -- there is no sig. ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
