Re: [PATCH] intel_irq_remapping: Clean up x2apic optout securitywarning mess

From: Don Zickus
Date: Mon Feb 04 2013 - 13:20:33 EST


On Fri, Feb 01, 2013 at 02:57:43PM -0800, Andy Lutomirski wrote:
> Current kernels print this on my Dell server:
>
> ------------[ cut here ]------------
> WARNING: at drivers/iommu/intel_irq_remapping.c:542
> intel_enable_irq_remapping+0x7b/0x27e()
> Hardware name: PowerEdge R620
> Your BIOS is broken and requested that x2apic be disabled
> This will leave your machine vulnerable to irq-injection attacks
> Use 'intremap=no_x2apic_optout' to override BIOS request
> [...]
> Enabled IRQ remapping in xapic mode
> x2apic not enabled, IRQ remapping is in xapic mode
>
> This is inconsistent with itself -- interrupt remapping is *on*.
>
> Fix the mess by making the warnings say what they mean and my making
> sure that compatibility format interrupts (the dangerous ones) are
> disabled if x2apic is present regardless of BIOS settings.

Yeah, this fixes the problem on our end too. Thank Andy!

Cheers,
Don
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