Re: Nested SVM and migration

Avi Kivity
2010-02-22T16:59:33Z

On 02/22/2010 06:56 PM, Zachary Amsden wrote:
>
>> In the SVM case this still leaves the problem that the MSR bitmap must
>> be read again from guests memory on unfreeze but that is not a real
>> problem.
>
> This is easily solved by shadowing the MSR bitmap. Too bad we have to
> do it, but at least the state isn't hidden in a non-extractable field
> inside the processor.
>

We could write-protect the bitmaps and shadow them lazily when changed
(which should be never; also improves vmentry time). Write protecting
is bad since it breaks up large pages, but is necessary for exposing npt
to the guest, which is needed for reasonable performance, so we may as
well do it.

--
error compiling committee.c: too many arguments to function