Magenheimer, Dan (HP Labs Fort Collins)
2006-Feb-17 23:26 UTC
RE: [Xen-devel] Re: user/hypervisor address space solution
> But while we''re on the subject, I recall hearing that IA64 > has an issue > with TLB faults when accessing domain virtual addresses. Could you > elaborate on that? I guess you''re using a software-controlled TLB, and > when a fault occurs you need to call up to Linux to handle it?This is a theoretical problem that is believed to be a possible issue. Yes, if a user access is made that is not in the TLB, a trap occurs and it is at least conceivable that Xen will be unable to resolve it and the trap would be reflected to the guest. This would necessitate a restart of the hypercall and, if a hypercall requires two user accesses to different pages (perhaps maliciously), it seems possible that thrashing could occur. This deserves some detailed study but there have been much bigger fish to fry :-) Dan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel