--- wikisrc/ports/xen/howto.mdwn 2014/12/31 00:33:48 1.69 +++ wikisrc/ports/xen/howto.mdwn 2015/01/17 01:32:12 1.75 @@ -274,23 +274,15 @@ For debugging, one may copy xen-debug.gz to DIAGNOSTIC and DEBUG in NetBSD. xen-debug.gz is basically only useful with a serial console. Then, place a NetBSD XEN3_DOM0 kernel in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz -of a NetBSD build. Both xen and NetBSD may be left compressed. (If -using i386, use releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.) - -With Xen as the kernel, you must provide a dom0 NetBSD kernel to be -used as a module; place this in /. Suitable kernels are provided in -releasedir/binary/kernel: - - i386 XEN3_DOM0 - i386 XEN3PAE_DOM0 - amd64 XEN3_DOM0 - -The first one is only for use with Xen 3.1 and i386-mode Xen (and you -should not do this). Current Xen always uses PAE on i386, but you -should generally use amd64 for the dom0. In a dom0 kernel, kernfs is -mandatory for xend to comunicate with the kernel, so ensure that /kern -is in fstab. TODO: Say this is default, or file a PR and give a -reference. +of a NetBSD build. If using i386, use +releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz. (If using Xen +3.1 and i386, you may use XEN3_DOM0 with the non-PAE Xen. But you +should not use Xen 3.1.) Both xen and the NetBSD kernel may be (and +typically are) left compressed. + +In a dom0 kernel, kernfs is mandatory for xend to comunicate with the +kernel, so ensure that /kern is in fstab. TODO: Say this is default, +or file a PR and give a reference. Because you already installed NetBSD, you have a working boot setup with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the @@ -302,8 +294,8 @@ See boot.cfg(5) for an example. The bas menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M which specifies that the dom0 should have 256M, leaving the rest to be -allocated for domUs. In an attempt to add performance, one can also -add +allocated for domUs. To use In an attempt to add performance, one can +also add dom0_max_vcpus=1 dom0_vcpus_pin @@ -875,13 +867,14 @@ NetBSD as a domU in a VPS The bulk of the HOWTO is about using NetBSD as a dom0 on your own hardware. This section explains how to deal with Xen in a domU as a virtual private server where you do not control or have access to the -dom0. +dom0. This is not intended to be an exhaustive list of VPS providers; +only a few are mentioned that specifically support NetBSD. VPS operators provide varying degrees of access and mechanisms for configuration. The big issue is usually how one controls which kernel is booted, because the kernel is nominally in the dom0 filesystem (to -which VPS users do not normally have acesss). - +which VPS users do not normally have acesss). A second issue is how +to install NetBSD. A VPS user may want to compile a kernel for security updates, to run npf, run IPsec, or any other reason why someone would want to change their kernel. @@ -892,6 +885,10 @@ or to select from a prepopulated list. kernel from the domU filesystem. This is closer to a regular physical computer, where someone who controls a machine can replace the kernel. +A second issue is multiple CPUs. With NetBSD 6, domUs support +multiple vcpus, and it is typical for VPS providers to enable multiple +CPUs for NetBSD domUs. + pygrub ------- @@ -907,15 +904,24 @@ pvgrub is a version of grub that uses PV calls. It is booted from the dom0 as the domU kernel, and then reads /grub/menu.lst and loads a kernel from the domU filesystem. -[prgmr.com](http://prgmr.com/) uses this approach to let users choose -their own operating system and kernel. See then [prgmr.com NetBSD -HOWTO](http://wiki.prgmr.com/mediawiki/index.php/NetBSD_as_a_DomU). - -Because [grub's FFS code](http://xenbits.xensource.com/hg/xen-unstable.hg/file/bca284f67702/tools/libfsimage/ufs/fsys_ufs.c) -appears not to support all aspects of modern FFS, -typically one has an ext2 or FAT partition for the kernel, so that -grub can understand it, which leads to /netbsd not being the actual -kernel. One must remember to update the special boot partiion. +[Panix](http://www.panix.com/) lets users use pvgrub. Panix reports +that pvgrub works with FFsv2 with 16K/2K and 32K/4K block/frag sizes +(and hence with defaults from "newfs -O 2"). See [Panix's pvgrub +page](http://www.panix.com/v-colo/grub.html), which describes only +Linux but should be updated to cover NetBSD :-). + +[prgmr.com](http://prgmr.com/) also lets users with pvgrub to boot +their own kernel. See then [prgmr.com NetBSD +HOWTO](http://wiki.prgmr.com/mediawiki/index.php/NetBSD_as_a_DomU) +(which is in need of updating). + +It appears that [grub's FFS +code](http://xenbits.xensource.com/hg/xen-unstable.hg/file/bca284f67702/tools/libfsimage/ufs/fsys_ufs.c) +does not support all aspects of modern FFS, but there are also reports +that FFSv2 works fine. At prgmr, typically one has an ext2 or FAT +partition for the kernel with the intent that grub can understand it, +which leads to /netbsd not being the actual kernel. One must remember +to update the special boot partiion. Amazon ------ @@ -939,10 +945,11 @@ TODO items for improving NetBSD/xen * Get PCI passthrough working on Xen 4.2 (or 4.4). * Get pvgrub into pkgsrc, either via xentools or separately. * grub - * Add support to pkgsrc grub2 for UFS2 and arbitrary + * Check/add support to pkgsrc grub2 for UFS2 and arbitrary fragsize/blocksize (UFS2 support may be present; the point is to make it so that with any UFS1/UFS2 filesystem setup that works with NetBSD grub will also work). + See [pkg/40258](http://gnats.netbsd.org/40258). * Push patches upstream. * Get UFS2 patches into pvgrub. * Add support for PV ops to a version of /boot, and make it usable as