On 26/12/2013 21:43, Samuel Thibault wrote: > Hello, > > Andrew Cooper, le Thu 26 Dec 2013 22:17:38 +0100, a écrit : >> I believe can make a topology-xen.c without too much trouble. It likely >> wants to checked before an os-specific hook (Xen dom0's come in at least >> Linux, FreeBSD, NetBSD flavours which have mainstream support) >> Are there any hints/suggestion/information about how to go about >> integrating this? > Yes, you can probably play with plugin priorities for that. See for > instance what happens with the pci plugins.
Are there any hints on exactly what I have to tweak to get topology-xen.c picked up properly? I pesuaded ./configure to put it in static-components.h but not to actually attempt to build topology-xen.c. (I shall continue hacking in the meantime) > >> What is the policy with regards to linking against >> new libraries by default (or perhaps by an --enable-xen configure >> option)? > By default we usually link against anything which is there, so linking > against libxenctrl is fine. > > IIRC hypercalls through libxenctrl are reserved to root? We'd like to > let normal users be able to get the topology... Under linux, hypercalls are restricted to users who can open /dev/xen/privcmd, and issue ioctl()s. At the moment, this is certainly restricted to root users only. This is because toolstacks (who are currently the only non-debug users of hypercalls in dom0 I am aware of) really do have to be root to function correctly. Having said that, there is an argument to be made for a relaxation of the requirements for read-only hypercalls. Either way, that would be a change of the privcmd driver. hwloc would work fine either way, as libxenctrl does its checking based on whether it can open /dev/xen/privcmd, rather than whether it is root or not. ~Andrew
