On Tuesday 23 September 2008 16:47:54 Jan Kiszka wrote: > Yang, Sheng wrote: > > On Monday 22 September 2008 19:00:38 Avi Kivity wrote: > >> Jan Kiszka wrote: > >>>> Maybe the answer is to generate the local nmi via an IPI-to-self > >>>> command to the local apic. > >>> > >>> Going this way leaves me with a few questions: Will it be OK for the > >>> related mainainers to export the required service? > >> > >> If we can make a case for it (I think we can), then I don't see why not. > >> > >> Sheng, can you confirm that 'int 2' is problematic, and that > >> nmi-via-lapic is the best workaround? > > > > Just back from vacation... :) > > > > Jan said is true, "int 2" itself won't block subsequent NMIs. But I think > > it's too obviously as a hardware issue when using with NMI exiting=1 in > > vmx nonroot mode, so I have checked it with my colleague, finally found > > these in SDM 3B 23-2: > > > > The following bullets detail when architectural state is and is not > > updated in response to VM exits: > > • If an event causes a VM exit *directly*, it does not update > > architectural state as it would have if it had it not caused the VM exit: > > [...] > > — *An NMI causes subsequent NMIs to be blocked*, but only after the VM > > exit completes. > > > > So we needn't worry about that, and this shouldn't cause any trouble > > AFAIK... > > Fine, problems--. :) > > > Jan, seems we need to do more investigating on the issues you met... > > Sorry, which one do you mean now?
You said "Only true until you have multiple unsynchronized NMI sources, e.g. inter-CPU NMIs of kgdb + a watchdog. I just stumbled over several bugs in kvm's and my own NMI code that were triggered by such a scenario (sigh...)." ? If it's not related to this one. That's fine. :) -- regards Yang, Sheng > > Jan > > -- > Siemens AG, Corporate Technology, CT SE 2 > Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
