Re: EFI mixed mode + perf = rampant triple faults

From: Andy Lutomirski
Date: Wed Jan 14 2015 - 13:38:52 EST


On Wed, Jan 14, 2015 at 10:35 AM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Wed, Jan 14, 2015 at 10:27:47AM -0800, Andy Lutomirski wrote:
>> How are you manually triggering an MCE? I've been playing with some
>> MCE stuff recently, but the only reasonably reliable way I know of to
>> trigger an MCE is using WHEA, and I don't have a box with WHEA, and I
>> assume your ASUS T100 doesn't either.
>
> asm volatile("int $18");

That's not a real MCE, though -- it happens synchronously instead of
at MCE priority with all the associated messiness. Or is the idea to
just stick that in after switching to the 32-bit mode being tested?

--Andy

>
>> Tianocore makes assumptions about the kernel's GDT layout? Yuck.
>
> Yuck indeed.
>
> --
> Regards/Gruss,
> Boris.
>
> Sent from a fat crate under my desk. Formatting is fine.
> --



--
Andy Lutomirski
AMA Capital Management, LLC
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