>>> On 19.04.17 at 15:58, <andrew.coop...@citrix.com> wrote: > On 19/04/17 14:50, Yu Zhang wrote: >> >> >> On 4/19/2017 9:34 PM, Jan Beulich wrote: >>>>>> On 19.04.17 at 13:44, <yu.c.zh...@linux.intel.com> wrote: >>>> On 4/19/2017 7:19 PM, Jan Beulich wrote: >>>>>>>> On 19.04.17 at 11:48, <yu.c.zh...@linux.intel.com> wrote: >>>>>> Does hypervisor need to differentiate dom0 kernel and its >>>>>> user space? >>>>> If we want to para-virtualize the feature, then yes. Otherwise >>>>> we can't assume the guest kernel would deal with user mode faults, >>>>> so we'd have to. Arguably there could be a non-default mode in >>>>> which we don't (forcing such applications to get a signal or crash). >>>> For UMIP is to be para-virtualized, is it OK to give dom0 kernel the >>>> physical value >>>> if instructions are triggered in the kernel? >>> Why would you want to special case Dom0 here? I don't see >>> anything wrong with giving Dom0 the real values, but since you'll >>> have to not give DomU-s the real values, you'd then add more >>> code to treat Dom0 specially. Simply give everyone fake values. >> >> Oh. So in such case should return 0 to the dom0 kernel I guess? >> >> Here come a dumb question: does other pv domain also run in ring 3 in >> vmx root mode, >> or simply in vmx non-root ring 0? :) > > PV guests execute exclusively in non-root mode.
In root mode, you mean. Jan > 32bit PV guest kernels execute in ring 1. > 64bit PV guest kernels execute in ring 3. > > ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
