>>> Nick Piggin <[EMAIL PROTECTED]> 25.01.08 09:38 >>> >On Friday 25 January 2008 19:15, Jan Beulich wrote: >> Actually, another thought: permitting (and handling) spurious faults for >> kernel mappings conflicts with NMI handling, i.e. great care would be >> needed to ensure the NMI path cannot touch any such mapping. So >> even the present Xen/Linux Dom0 implementation may have some >> (perhaps unlikely) problems here, and it would get worse if we added >> e.g. a virtual watchdog NMI (something I am considering, which would >> then extend the problem to DomU-s). > >Can you explain how they conflict?
In the same way as vmalloc faults do (which is why vmalloc_sync_all() got introduced): a page fault nested inside an NMI will, by virtue of executing IRET, prematurely tell the processor that NMI handling is done (and specifically unmask further NMIs). Jan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
