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Andy Lutomirski authored
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. With this patch applied, the output is: Your BIOS is broken and requested that x2apic be disabled. This will slightly decrease performance. 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 should make us as or more secure than we are now and replace a rather scary warning with a much less scary warning on silly but functional systems. Signed-off-by:
Andy Lutomirski <luto@amacapital.net> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Alex Williamson <alex.williamson@redhat.com> Link: http://lkml.kernel.org/r/2011b943a886fd7c46079eb10bc24fc130587503.1359759303.git.luto@amacapital.netSigned-off-by:
Ingo Molnar <mingo@kernel.org>
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