Both systemsim and my powerpc server boots with MSR_HV=1, i.e, hypervisor state. Is there away to fix that ? writing to the MSR cannot work according the documentation ( and reality ).
On Sat, Oct 6, 2018 at 3:27 PM Segher Boessenkool <seg...@kernel.crashing.org> wrote: > > On Sat, Oct 06, 2018 at 12:19:45PM +0300, Raz wrote: > > Hey > > How does HVSC works ? > > I looked in the code and LoPAR documentation. It looks like there is > > vector called > > system_call_pSeries ( at 0xc00 ) that is supposed to be called when we > > invoke HVSC from kernel > > mode. > > Now, I wrote a NULL call HSVC and patched the exceptions-64s.S to > > return RFID immediately. > > This does not work. > > Would you be so kind to explain how HVSC works ? > > thank you > > If your kernel is not running in hypervisor mode, sc 1 does not call the > kernel (but the hypervisor, instead). If your kernel _is_ running in > hypervisor mode, sc 1 does the same as sc 0, a normal system call. > > I don't know which it is for you; you didn't say. > > I have no idea what "a NULL call HSVC" means. If you make exception c00 > return immediately (as you suggest) then you have made all system calls > non-functional, which indeed is unlikely to work as you want. > > > Segher