Re: [PATCH] x86: kvm: reset the bootstrap processor when it gets an INIT

Gleb Natapov
2013-03-11T14:12:52Z

On Mon, Mar 11, 2013 at 03:10:45PM +0100, Jan Kiszka wrote:
> On 2013-03-11 15:09, Gleb Natapov wrote:
> > On Mon, Mar 11, 2013 at 03:06:18PM +0100, Jan Kiszka wrote:
> >> On 2013-03-11 15:05, Gleb Natapov wrote:
> >>> On Mon, Mar 11, 2013 at 03:01:40PM +0100, Jan Kiszka wrote:
> >>>>> We are not moving away from mp_state, we are moving away from using
> >>>>> mp_state for signaling because with nested virt INIT does not always
> >>>>> change mp_state, not only that it can change mp_state long after signal
> >>>>> is received after vmx off is done.
> >>>>
> >>>> Right.
> >>>>
> >>>> BTW, for that to happen, we will also need to influence the INIT level.
> >>>> Unless I misread the spec, INIT is blocked while in root mode, and if
> >>>> you deassert INIT before leaving root (vmxoff, vmenter), nothing
> >>>> actually happens. So what matters is the INIT signal level at the exit
> >>>> of root mode.
> >>>>
> >>> You are talking about INIT# signal received via CPU pin, right? I think
> >>> INIT send by IPI cannot go away.
> >>
> >> Why shouldn't it? Besides edge, there is also level-triggered INIT.
> >>
> > OK, so level-triggered INIT can be de-asserted what about edge triggered
> > one? :)
>
> It should be lost while in root mode.
>
Ah, that's great. Removes some potential complications.

--
Gleb.