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    SubjectRe: [PATCH] x86: kvm: reset the bootstrap processor when it gets an INIT
    On 2013-03-11 15:12, Gleb Natapov wrote:
    > 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.

    Again, that's my interpretation. I didn't check this against real HW
    yet. It just makes most sense, given what I read.

    Jan

    --
    Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
    Corporate Competence Center Embedded Linux


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