Without it Linux is not able to parse the x2APIC ACPI MADT entries crafted by Xen when booted in PVH mode, following log is from one of the dom0pvh jobs:
ACPI: x2apic entry ignored ACPI: x2apic entry ignored ACPI: x2apic entry ignored ACPI: x2apic entry ignored IOAPIC[0]: apic_id 0, version 17, address 0xfec00000, GSI 0-23 IOAPIC[1]: apic_id 1, version 17, address 0xfec20000, GSI 24-55 ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl) ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 low level) Using ACPI (MADT) for SMP configuration information smpboot: Boot CPU (id 0) not listed by BIOS smpboot: Allowing 1 CPUs, 0 hotplug CPUs Note that PVH mode only creates x2APIC entries for simplicity, and because x2APIC mode is always provided to PVH guests. Not adding x2APIC support forces Linux to boot in UP mode, since x2APIC entries contain the information of additional processors available on the system. Signed-off-by: Roger Pau Monné <roger....@citrix.com> --- ts-kernel-build | 3 +++ 1 file changed, 3 insertions(+) diff --git a/ts-kernel-build b/ts-kernel-build index 89cdafcb..6c8f1d6a 100755 --- a/ts-kernel-build +++ b/ts-kernel-build @@ -622,6 +622,9 @@ esac # Disable components that don't build setopt CONFIG_TEGRA_HOST1X n +# Enable x2APIC support for PVH mode +setopt CONFIG_X86_X2APIC y + exit 0 END } -- 2.26.0
