1 Reply Latest reply on May 17, 2017 4:46 PM by Intel Corporation

    No x2apic on Westmere/Tylersburg


      I have a Westmere/Tylersburg system (CPU: 2 x X5672, Chipset: Intel 5520 Tylersburg) - sitting on a Supermicro X8DTN+-F

      I believe I should have a x2APIC


      lspci says


      00:13.0 PIC: Intel Corporation 7500/5520/5500/X58 I/O Hub I/OxAPIC Interrupt Controller (rev 22) (prog-if 20 [IO(X)-APIC])


      Both x2apic as well as IRQ rerouting are enabled in my kernel, but unfortunately no x2apic flag is visible in /proc/cpuinfo


      Now I read, that the Tylersburg chipset has trouble with IRQ rerouting, which seems a prerequisite for x2APIC operation.

      (see: [vfio-users] Intel x2APIC and APIC Virtualization (APICv or vAPIC) ), so I wanted to ask if that's a hardware-given

      blocker or if this is again something that could be circumvented by some BIOS settings?


      The machine in question has 144GB RAM and I intend to have a quite extensive set of VMs running on it, so I'd naturally

      like to make use of x2apic as it gives me quite some difference in VM responsiveness on other machines with x2apic enabled.