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Keir Fraser
a2b4af7d77
- Have the buid system generate a file which exports the install paths for the hotplug scripts and stubdom / stubdom-dm - Move file generation code from tools/python/Makefile into a gmake macro in Config.mk to avoid maintenance of three duplicates each with its own tweaks and bugs - Export gmake variables into ioemu as shell variables for upcoming ioemu patches - Do above as a gmake macro to avoid maintenance of several duplicates - Adjust hotplug scripts to find the right xen binaries from the install directory - Adjust stubdom-dm to use the install directories Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
IOEMU stubdom
=============
This boosts HVM performance by putting ioemu in its own lightweight domain.
General Configuration
=====================
Due to a race between the creation of the IOEMU stubdomain itself and allocation
of video memory for the HVM domain, you need to avoid the need for ballooning,
by using the hypervisor dom0_mem= option for instance.
There is a sample configuration set in xmexample.hvm-stubdom
In your HVM config "hvmconfig" use /usr/lib/xen/bin/stubdom-dm as dm script:
device_model = '/usr/lib/xen/bin/stubdom-dm'
To run
======
mkdir -p /exports/usr/share/xen/qemu
ln -s /usr/share/xen/qemu/keymaps /exports/usr/share/xen/qemu
mkdir -p /exports/var/lib
ln -s /var/lib/xen /exports/var/lib
/usr/sbin/fs-backend &
xm create hvmconfig
PV-GRUB
=======
This replaces pygrub to boot domU images safely: it runs the regular grub
inside the created domain itself and uses regular domU facilities to read the
disk / fetch files from network etc. ; it eventually loads the PV kernel and
chain-boots it.
Configuration
=============
In your PV config,
- use /usr/lib/xen/boot/pv-grub.gz as kernel:
kernel = "/usr/lib/xen/boot/pv-grub.gz"
- set the path to menu.lst, as seen from the domU, in extra:
extra = "(hd0,0)/boot/grub/menu.lst"
you can also use a tftp path (dhcp will be automatically performed):
extra = "(nd)/somepath/menu.lst"
or you can set it in option 150 of your dhcp server and leave extra empty
Limitations
===========
- You can not boot a 64bit kernel with a 32bit-compiled PV-GRUB and vice-versa.
To cross-compile a 32bit PV-GRUB,
export XEN_TARGET_ARCH=x86_32
- bootsplash is supported, but the ioemu backend does not yet support restart
for use by the booted kernel.
Your own stubdom
================
By running
cd stubdom/
make c-stubdom
or
cd stubdom/
make caml-stubdom
you can compile examples of C or caml stub domain kernels. You can use these
and the relevant Makefile rules as basis to build your own stub domain kernel.
Available libraries are libc, libxc, libxs, zlib and libpci.