--- wikisrc/ports/xen/howto.mdwn 2014/12/24 14:35:23 1.28 +++ wikisrc/ports/xen/howto.mdwn 2014/12/24 15:17:25 1.29 @@ -27,11 +27,12 @@ code for Xen and need not be aware that Attempts to access hardware registers are trapped and emulated. This style is less efficient but can run unmodified guests. -Generally any amd64 machine will work with Xen and PV guests. For -HVM guests, the VT or VMX cpu feature (Intel) or SVM/HVM/VT (amd64) -is needed; "cpuctl identify 0" will show this. Xen 4.2 is the last -version for support for using i386 as a host. TODO: Clean up and -check the above features. +Generally any amd64 machine will work with Xen and PV guests. In +theory i386 computers without amd64 support can be used for Xen <= +4.2, but we have no recent reports of this working (this is a hint). +For HVM guests, the VT or VMX cpu feature (Intel) or SVM/HVM/VT +(amd64) is needed; "cpuctl identify 0" will show this. TODO: Clean up +and check the above features. At boot, the dom0 kernel is loaded as a module with Xen as the kernel. The dom0 can start one or more domUs. (Booting is explained in detail @@ -89,7 +90,7 @@ matching versions. xenkernel3 and xenkernel33 provide Xen 3.1 and 3.3. These no longer receive security patches and should not be used. Xen 3.1 supports PCI -passthrough. +passthrough. Xen 3.1 supports non-PAE on i386. xenkernel41 provides Xen 4.1. This is no longer maintained by Xen, but as of 2014-12 receives backported security patches. It is a @@ -117,7 +118,9 @@ NetBSD The netbsd-5, netbsd-6, netbsd-7, and -current branches are all reasonable choices, with more or less the same considerations for non-Xen use. Therefore, netbsd-6 is recommended as the stable version -of the most recent release. +of the most recent release for production use. For those wanting to +learn Xen or without production stability concerns, netbsd-7 is likely +most appropriate. As of NetBSD 6, a NetBSD domU will support multiple vcpus. There is no SMP support for NetBSD as dom0. (The dom0 itself doesn't really @@ -127,13 +130,20 @@ a normal computer.) Architecture ------------ -Xen is basically amd64 only at this point. One can either run i386 -domains or amd64 domains. If running i386, PAE versions are required, -for both dom0 and domU. These versions are built by default in NetBSD -releases. While i386 dom0 works fine, amd64 is recommended as more -normal. (Note that emacs (at least) fails if run on i386 with PAE when -built without, and vice versa, presumably due to bugs in the undump -code.) +Xen itself can run on i386 or amd64 machines. (Practically, almost +any computer where one would want to run Xen supports amd64.) If +using an i386 NetBSD kernel for the dom0, PAE is required (PAE +versions are built by default). While i386 dom0 works fine, amd64 is +recommended as more normal. + +Xen 4.2 is the last version to support i386 as a host. TODO: Clarify +if this is about the CPU having to be amd64, or about the dom0 kernel +having to be amd64. + +One can then run i386 domUs and amd64 domUs, in any combination. If +running an i386 NetBSD kernel as a domU, the PAE version is required. +(Note that emacs (at least) fails if run on i386 with PAE when built +without, and vice versa, presumably due to bugs in the undump code.) Recommendation -------------- @@ -503,7 +513,7 @@ working vif-bridge is also provided with #!/bin/sh #============================================================================ - # $NetBSD: howto.mdwn,v 1.27 2014/12/24 08:32:49 jnemeth Exp $ + # $NetBSD: howto.mdwn,v 1.28 2014/12/24 14:35:23 gdt Exp $ # # /usr/pkg/etc/xen/vif-bridge #