Messages in this thread | | | Date | Wed, 19 Dec 2012 08:10:21 -0800 | From | "H. Peter Anvin" <> | Subject | Re: Why Linux kernel forced to enter X2APIC mode( just because of booting cpu has supported x2apic) without depending on BIOS' setting in MSR->x2apic enablement bit ? |
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On 12/18/2012 09:49 AM, Yinghai Lu wrote: > > So you need to make cpuid show does not support x2apic --- check with > intel they have way to do that. >
No, but there is a flag in ACPI that "this BIOS is broken with x2APIC". Setting that flag as opposed to fixing the bugs, though is very much not recommended, however; the lack of interrupt routing means there are ways for a rogue device to compromise the security provided by VT-d, see:
http://www.invisiblethingslab.com/resources/2011/Software%20Attacks%20on%20Intel%20VT-d.pdf
-hpa
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