kernel-packages team mailing list archive

[Rafael David Tinoco <tinhocas@xxxxxxxxx>]

Dave,

This message is being given to let you know that your BIOS
(EFI/firmware/..) is "asking" the OS to NOT USE x2apic (and this happens
on HP Proliant Servers). This is because, before Gen7, Proliant servers
did not support X2APIC (a new Programmable Interrupt Controller) and had
to operate into "XAPIC"/"APIC" compatible mode (even if their CPU
supported X2APIC).

For Proliant Servers >= Gen8 you can say to Linux to "ignore" this
request from firmware. To do that you change

GRUB_CMDLINE_LINUX_DEFAULT="..." to
GRUB_CMDLINE_LINUX_DEFAULT="... intremap=no_x2apic_optout"

inside /etc/default/grub and run "update-grub" command (rebooting your
server later on).

This is because Gen8 are X2APIC capable but the firmware still asks OS
not to enable it (as I was told by HP).

If you use HP Proliant Servers < Gen8 you have to use:

"nox2apic intermap=off"

For not having problems regarding IRQ handling, deactivating x2apic.

Note that if you are using HP Proliant Servers you have to be aware of
the following bug also:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1318551

adding "intel_idle.max_cstate=0" to the cmdline also.

-- 
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https://bugs.launchpad.net/bugs/1398497

Title:
  HP Proliant Serverrs - DL360 and DL380 Gen8 - Precise Kernel Panic -
  General Protection Fault and X2APIC/XAPIC boot parameters

Status in linux package in Ubuntu:
  In Progress
Status in linux source package in Precise:
  In Progress

Bug description:
  It was brought to my attention the following situation:

  """
  We massively upgraded our Ubuntu 12.04 servers (most of them are HP
  DL360p Gen8 or DL380 Gen8) to 3.2.0-67 kernel And in the last 2-3
  days we already had to reboot 5 of them because they completely hang

  Some of them had the following messages under syslog :
  kernel: [384707.675479] general protection fault: 0000 [#5666] SMP

  others had :
  kernel: [950725.612724] BUG: unable to handle kernel paging request

  All of them have this also :
  your BIOS is broken and requested that x2apic be disabled
  """

  Comments bellow

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