Zachary Amsden wrote: > Jeremy Fitzhardinge wrote: >> The XEN config option enables the Xen paravirt_ops interface, which is >> installed when the kernel finds itself running under Xen. (By some >> as-yet fully defined mechanism, implemented in a future patch.) >> >> Xen is no longer a sub-architecture, so the X86_XEN subarch config >> option has gone. >> >> The disabled config options are: >> - PREEMPT: Xen doesn't support it >> - HZ: set to 100Hz for now, to cut down on VCPU context switch rate. >> This will be adapted to use tickless later. >> - kexec: not yet supported >> >> Signed-off-by: Jeremy Fitzhardinge <jeremy at xensource.com> >> Signed-off-by: Ian Pratt <ian.pratt at xensource.com> >> Signed-off-by: Christian Limpach <Christian.Limpach at cl.cam.ac.uk> >> Signed-off-by: Chris Wright <chrisw at sous-sol.org> >> > > We do support different HZ values, although 100HZ is actually > preferable for us, so I don't object to that. Ditto for kvm. > PREEMPT is supported by us, but not as tested as I would like, so I > also don't object to dropping it for generic paravirt guests - Rusty - > Avi any objections to dropping preempt in terms of lguest/KVM > paravirtualization? I don't have any objections myself, but Ingo (who has done the bulk of the kvm paravirt work; cc'ed) uses PREEMPT_RT, so he will certainly object. > > Paravirt-ops definitely needs a hook for kexec, although we should not > disable kexec for the natively booted paravirt-ops. Eric - is there a > way to disable it at runtime? kvm paravirt should work correctly with kexec. > > We do support the doublefault task gate, and it would be good to keep > it, but I can't complain so much if it is gone from generic paravirt > kernels for now, because it is non-essential, and generally fatal > anyway. We do need it for native boots of paravirt-ops kernels, > however, so turning off the config option still needs to be revisited. kvm doesn't support task gates (a task switch will immediately kill the guest). -- error compiling committee.c: too many arguments to function
