[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] about fully UMIP support in Xen
On 19/04/17 15:07, Jan Beulich wrote: >>>> On 19.04.17 at 15:58, <andrew.cooper3@xxxxxxxxxx> 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.zhang@xxxxxxxxxxxxxxx> wrote: >>>>> On 4/19/2017 7:19 PM, Jan Beulich wrote: >>>>>>>>> On 19.04.17 at 11:48, <yu.c.zhang@xxxxxxxxxxxxxxx> 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. I do. (oops. Sorry.) ~Andrew > > Jan > >> 32bit PV guest kernels execute in ring 1. >> 64bit PV guest kernels execute in ring 3. >> >> ~Andrew > > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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