--- wikisrc/ports/xen/howto.mdwn 2016/12/20 19:59:38 1.132 +++ wikisrc/ports/xen/howto.mdwn 2016/12/20 20:59:49 1.133 @@ -81,6 +81,11 @@ of Xen version and NetBSD version. This which version to choose. Versions not in pkgsrc and older unsupported versions of NetBSD are intentionally ignored. +The term "amd64" is used to refer to both the NetBSD port and to the +hardware architecture on which it runs. (Such hardware is made by +both Intel and AMD, and in 2016 a normal PC has this CPU +architecture.) + Xen --- @@ -89,38 +94,39 @@ xenkernel and xentools. We will refer o but note that both packages must be installed together and must have matching versions. -xenkernel3 provides Xen 3.1. It is no longer maintained by Xen, and the last applied security patch was in -2011. Thus, it should not be used. It supports PCI passthrough, -which is why people use it anyway. Xen 3.1 supports i386, both PAE and -non-PAE. +xenkernel3 provides Xen 3.1. It is no longer maintained by Xen, and +the last applied security patch was in 2011. Thus, it should not be +used. It supports PCI passthrough, which is why people use it anyway. +Xen 3.1 runs on i386 (both non-PAE and PAE) and amd64 hardware. xenkernel33 provides Xen 3.3. It is no longer maintained by Xen, and the last applied security patch was in 2012. Thus, it should not be -used. Xen 3.3 supports i386, but only in PAE mode. There are no good +used. Xen 3.3 runs on i386 PAE and amd64 hardware. There are no good reasons to run this version. xenkernel41 provides Xen 4.1. It is no longer maintained by Xen, but -as of 2016-12 received backported security patches. Xen 4.1 supports -i386, but only in PAE mode. There are no good reasons to run this +as of 2016-12 received backported security patches. Xen 4.1 runs on +i386 PAE and amd64 hardware. There are no good reasons to run this version. xenkernel42 provides Xen 4.2. It is no longer maintained by Xen, but -as of 2016-12 received backported security patches. Xen 4.2 supports -i386, but only in PAE mode. The only reason to run this is if you -need to use xm instead of xl, or if you need to run an i386 dom0 -(because your hardware is i386 only). +as of 2016-12 received backported security patches. Xen 4.2 runs on +i386 PAE and amd64 hardware. The only reason to run this is if you +need to use xm instead of xl, or if you need to run on hardware that +supports i386 but not amd64. (This might also be useful if you need +an i386 dom0, if it turns out that an amd64 Xen kernel and an i386 +dom0 is problematic.) xenkernel45 provides Xen 4.5. As of 2016-12, security patches were -released by Xen and applied to pkgsrc. Xen 4.5 requires using a dom0 -running NetBSD's amd64 port (Intel or AMD hardware is fine), but domUs -can be amd64 or i386 PAE. While slightly old, n4.5 has been tested and -run by others, so it is the conservative choice. +released by Xen and applied to pkgsrc. Xen 4.5 runs on amd64 hardware +only. While slightly old, 4.5 has been tested and run by others, so +it is the conservative choice. xenkernel46 provides Xen 4.6. It is new to pkgsrc as of 2016-05. As of 2016-12, security patches were released by Xen and applied to -pkgsrc. Xen 4.6 similarly requires a NetBSD/amd64 dom0, but domUs can -be amd64 or i386 PAE. For new installations, 4.6 is probably the -appropriate choice and it will likely soon be the standard approach. +pkgsrc. Xen 4.6 runs on amd64 hardware only For new installations, +4.6 is probably the appropriate choice and it will likely soon be the +standard approach. Xen 4.7 (released 2016-06) and 4.8 (released 2016-12) are not yet in pkgsrc. @@ -178,30 +184,32 @@ when using a dom0 as a normal computer.) Architecture ------------ -Xen itself can run on i386 (Xen < 3.1) or amd64 machines (all Xen +Xen itself can run on i386 (Xen < 4.2) or amd64 hardware (all Xen versions). (Practically, almost any computer where one would want to run Xen today supports amd64.) -Xen, the dom0 kernel, and each domU kernel can be either i386 or -amd64. When building a xenkernel package, one obtains i386 on an i386 -host, and amd64 on an amd64 host. If the Xen kernel is i386, then the -dom0 kernel and all domU kernels must be i386. With an amd64 Xen -kernel, an amd64 dom0 kernel is known to work, and an i386PAE dom0 -kernel should in theory work. An amd64 Xen/dom0 is known to support -both i386PAE and amd64 domUs. - -i386 dom0 and domU kernels must be PAE (except for Xen 3.1); these are -built by default. (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.) - -Because of the above, the standard approach is to use amd64 for the -dom0. - -Xen 4.2 is the last version to support i386 as a host. TODO: Clarify -if this is about the CPU, the Xen kernel, or the dom0 kernel having to -be amd64. - +Xen, the dom0 system, and each domU system can be either i386 or +amd64. When building a xenkernel package, one obtains an i386 Xen +kernel on an i386 host, and anamd64 Xen kernel on an amd64 host. If +the Xen kernel is i386, then the dom0 kernel and all domU kernels must +be i386. With an amd64 Xen kernel, an amd64 dom0 kernel is known to +work, and an i386 dom0 kernel should in theory work. An amd64 +Xen/dom0 is known to support both i386 and amd64 domUs. + +i386 dom0 and domU kernels must be PAE (except for an i386 Xen 3.1 +kernel, where one can use non-PAE for dom0 and all domUs); PAE +versions are included in the NetBSD default build. (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.) + +Because of the above, the standard approach is to use NetBSD/amd64 for +the dom0 and therefore an amd64 Xen kernel, and to use PAE kernels for +i386 domUs. + +Note that to use an i386 dom0 with Xen 4.5 or higher, one must build +an amd64 Xen kernel and install that on the system. One must also use +a PAE i386 kernel. There is no good reason to undertake these +contortions; you should use a NetBSD/amd64 dom0 system. Stability ---------