Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 21 May 2014 08:21:08 -0700 | Subject | Re: [RFC] x86_64: A real proposal for iret-less return to kernel |
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On May 21, 2014 2:46 AM, "Borislav Petkov" <bp@alien8.de> wrote: > > On Tue, May 20, 2014 at 07:39:31PM -0700, Andy Lutomirski wrote: > > So the issue here is that we can have an NMI followed immediately by > > an MCE. > > That part might need clarification for me: #MC is higher prio interrupt > than NMI so a machine check exception can interrupt the NMI handler at > any point.
Except that NMI can interrupt #MC at any point as well, I think.
> > But you're talking only about the small window when nmi_mce_nest_count > hasn't been incremented yet, right? I.e., this: > > "The result is that the only interrupt that can happen with > `nmi_mce_nest_count == 0` in NMI context is an MCE at the beginning or > end of the NMI handler." > > Correct?
Exactly.
> > -- > Regards/Gruss, > Boris. > > Sent from a fat crate under my desk. Formatting is fine. > --
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