On 2013-03-11 15:23, Paolo Bonzini wrote: > Il 11/03/2013 15:05, Gleb Natapov ha scritto: >> 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. > > Neither can go away. For INIT sent by IPI, 10.4.7 says: > > Only the Pentium and P6 family processors support the INIT-deassert IPI. > An INIT-disassert IPI has no affect on the state of the APIC, other than > to reload the arbitration ID register with the value in the APIC ID > register. > > 18.27.1 also says that "In the local APIC, NMI and INIT (except for INIT > deassert) are always treated as edge triggered interrupts". > > > For INIT#, the ICH9 chipset says that "INIT# is driven low for 16 PCI > clocks" when a soft reset is requested. So we can guess that INIT# is > also edge-triggered. Ah, ok. So, virtually, INIT stays asserted until it can be delivered in form of a reset or a vmexit. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
