xen: disable ACPI NUMA for PV guests

Xen does not currently expose PV-NUMA information to PV
guests. Therefore disable NUMA for the time being to prevent the
kernel picking up on an host-level NUMA information which it might
come across in the firmware.

[ Added comment - Jeremy ]

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 44dcad43989d..ed47d12fdecb 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1174,6 +1174,15 @@ asmlinkage void __init xen_start_kernel(void)
 
         xen_smp_init();
 
+#ifdef CONFIG_ACPI_NUMA
+        /*
+         * The pages we from Xen are not related to machine pages, so
+         * any NUMA information the kernel tries to get from ACPI will
+         * be meaningless.  Prevent it from trying.
+         */
+        acpi_numa = -1;
+#endif
+
         pgd = (pgd_t *)xen_start_info->pt_base;
 
         if (!xen_initial_domain())