greetings !!

i am using the the scheduler to implement some virtualisation stuff.
i would really appreciate some help regarding the following stuff i need to get done.

from the scheduler i need to do an upcall to a user level task . Can i use an ipc for this ?

from the user task ( the receiver of the above upcall from kernel  ) , i need to ( directly if possible ) switch to another task .
how do i do this ?

thanks !! any pointers would be really appreciated.
ej