On 4/19/2017 10:09 PM, Andrew Cooper wrote:
On 19/04/17 15:07, Jan Beulich wrote:
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.
I do.  (oops.  Sorry.)

Thanks a lot, Andrew & Jan.
And back to the schedule of this feature, are you working on it? Or any specific plan?
Is there anything we can do here in Intel?




32bit PV guest kernels execute in ring 1.
64bit PV guest kernels execute in ring 3.


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