PE-T620/RHEL6x: Your BIOS has requested that x2apic be disabled.

Giulio giulioo at gmail.com
Mon Jul 9 09:46:26 CDT 2012


PE-T620 (E5-2620, 64GB RAM)
BIOS: 1.2.6, Linux CENTOS 6.x 2.6.32-220.23.1.el6.x86_64 

On boot I get the message you find at the end of this email; the system
appears to work normally.

If I boot with 'intremap=no_x2apic_optout', as dmesg message suggests, then
the message goes away.

I'd like to know what Dell recommends:
1) Just ignore the message, do not use intremap boot option
	or
2) Use 'intremap=no_x2apic_optout' boot option

Thanks

===== dmesg with standard boot options:
...
HPET id 0 under DRHD base 0xdf900000
------------[ cut here ]------------
WARNING: at drivers/pci/intr_remapping.c:715
enable_intr_remapping+0x73/0x2af()
(Not tainted)
Hardware name: PowerEdge T620
Your BIOS has requested that x2apic be disabled.
This will leave your machine vulnerable to irq-injection attacks.
Use 'intremap=no_x2apic_optout' to override BIOS request.
Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.32-220.23.1.el6.x86_64 #1
Call Trace:
 [<ffffffff81069c97>] ? warn_slowpath_common+0x87/0xc0
 [<ffffffff81069d86>] ? warn_slowpath_fmt+0x46/0x50
 [<ffffffff81c50529>] ? enable_intr_remapping+0x73/0x2af
 [<ffffffff81c30279>] ? enable_IR+0x54/0x6e
 [<ffffffff81c30353>] ? enable_IR_x2apic+0xc0/0x221
 [<ffffffff81c2e1ba>] ? native_smp_prepare_cpus+0x143/0x389
 [<ffffffff81c1f740>] ? kernel_init+0x112/0x2fe
 [<ffffffff8100c14a>] ? child_rip+0xa/0x20
 [<ffffffff81c1f62e>] ? kernel_init+0x0/0x2fe
 [<ffffffff8100c140>] ? child_rip+0x0/0x20
---[ end trace a7919e7f17c0a725 ]---
Enabled IRQ remapping in xapic mode
x2apic not enabled, IRQ remapping is in xapic mode
Setting APIC routing to physical flat
  alloc irq_desc for 88 on node 0
  alloc kstat_irqs on node 0
  alloc irq_desc for 89 on node 0
  alloc kstat_irqs on node 0
...
=====


===== dmesg with intremap=no_x2apic_optout
...
HPET id 0 under DRHD base 0xdf900000
Enabled IRQ remapping in x2apic mode
Enabling x2apic
Enabled x2apic
Setting APIC routing to cluster x2apic
  alloc irq_desc for 88 on node 0
  alloc kstat_irqs on node 0
  alloc irq_desc for 89 on node 0
  alloc kstat_irqs on node 0
...
=====



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