[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH V2] xen: vmx: Use an INT 2 call to process real NMI's instead of self_nmi() in VMEXIT handler
At 17:03 +0000 on 15 Nov (1352998993), Mats Petersson wrote: > >On an AMD CPU we _don't_ have dedicated stacks for NMI or MCE when we're > >running a HVM guest, so the stack issue doesn't apply (but nested NMIs > >are still bad). > > > >On an Intel CPU, we _do_ use dedicated stacks for NMI and MCE in HVM > >guests. We don't really have to but it saves time in the context switch > >not to update the IDT. Using do_nmi() here means that the first NMI is > >handled on the normal stack instead. It's also consistent with the way > >we call do_machine_check() for the MCE case. But it needs an explicit > >IRET after the call to do_nmi() to make sure that NMIs get re-enabled. > > Both AMD and Intel has an identical setup with regard to stacks and > general "what happens when we taken one of these interrupts". My reading of svm_ctxt_switch_{to,from} makes me disagree with this. AFAICT, on SVM we're not using dedicated stacks at all. > The issues with regards to nesting of NMI and MCE is completely > different from the "how do we issue an NMI from the HVM handling code > when the guest got interrupted by NMI". Yes. As I said, we should take the fix to the VMX NMI handling now, and sort out the nesting separately. Tim. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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