powerpc/smp: Disable MC domain for shared processor

JIRA: https://issues.redhat.com/browse/RHEL-118964

commit 0e1c198
Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Date:   Thu Dec 14 23:37:12 2023 +0530

    powerpc/smp: Disable MC domain for shared processor

    Like L2-cache info, coregroup information which is used to determine MC
    sched domains is only present on dedicated LPARs. i.e PowerVM doesn't
    export coregroup information for shared processor LPARs. Hence disable
    creating MC domains on shared LPAR Systems.

    Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    Link: https://msgid.link/20231214180720.310852-3-srikar@linux.vnet.ibm.com

Signed-off-by: Phil Auld <pauld@redhat.com>

Author: auldp

arch/powerpc/kernel/smp.c

@@ -1068,6 +1068,10 @@ static struct cpumask *cpu_coregroup_mask(int cpu)
 
 static bool has_coregroup_support(void)
 {
+	/* Coregroup identification not available on shared systems */
+	if (is_shared_processor())
+		return 0;
+
 	return coregroup_enabled;
 }