[0/3] x86: enable x2APIC mode regardless of interrupt remapping support

Message

Roger Pau Monne Nov. 21, 2019, 3:54 p.m. UTC

Hello,

The following series aims to allow enabling x2APIC mode without
interrupt remapping support. The main usage of this would be in
virtualized environments, that usually provide x2APIC support but not
interrupt remapping.

See the last patch for some performance numbers of using x2APIC over
xAPIC when running Xen in pvshim mode.

Thanks, Roger.

Roger Pau Monne (3):
  x86/ioapic: only use dest32 with x2apic and interrupt remapping
    enabled
  x86/smp: check APIC ID on AP bringup
  x86/apic: allow enabling x2APIC mode regardless of interrupt remapping

 xen/arch/x86/apic.c    | 94 +++++++++++++++++++++---------------------
 xen/arch/x86/io_apic.c | 12 +++---
 xen/arch/x86/smpboot.c |  7 ++++
 3 files changed, 59 insertions(+), 54 deletions(-)