Re: [Lguest] lguest: unhandled trap

From: H. Peter Anvin
Date: Mon Oct 20 2008 - 15:06:06 EST

Ian Campbell wrote:

Wasn't there some concern about BIOSes which don't correctly reserve
their DMI tables? Or don't even have e820 maps? H. Peter once said:

It's pretty standard for 0xf0000...0x100000 to be marked RESERVED in
E820 on real hardware (including the system I'm typing on right now.)
It is so marked to indicate that hardware cannot be mapped into that
space. However, you can't rely on this fact -- heck, you can't rely on
E820 even existing on a real machine. I have specimens of real-life
machines that go both ways.

Not only that, but the ACPI spec states explicitly that the ISA magic areas should be handled without relying on E820.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at