spapr: move FORM1 verifications to post CAS

FORM2 NUMA affinity is prepared to deal with empty (memory/cpu less)
NUMA nodes. This is used by the DAX KMEM driver to locate a PAPR SCM
device that has a different latency than the original NUMA node from the
regular memory. FORM2 is also able  to deal with asymmetric NUMA
distances gracefully, something that our FORM1 implementation doesn't
do.

Move these FORM1 verifications to a new function and wait until after
CAS, when we're sure that we're sticking with FORM1, to enforce them.

Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20210920174947.556324-6-danielhb413@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 47 insertions, 6 deletions

diff --git a/hw/ppc/spapr_numa.c b/hw/ppc/spapr_numa.c
index dce9ce987a..6718c0fdd1 100644
--- a/hw/ppc/spapr_numa.c
+++ b/hw/ppc/spapr_numa.c
@@ -193,6 +193,48 @@ static void spapr_numa_define_FORM1_domains(SpaprMachineState *spapr)
 
 }
 
+static void spapr_numa_FORM1_affinity_check(MachineState *machine)
+{
+    int i;
+
+    /*
+     * Check we don't have a memory-less/cpu-less NUMA node
+     * Firmware relies on the existing memory/cpu topology to provide the
+     * NUMA topology to the kernel.
+     * And the linux kernel needs to know the NUMA topology at start
+     * to be able to hotplug CPUs later.
+     */
+    if (machine->numa_state->num_nodes) {
+        for (i = 0; i < machine->numa_state->num_nodes; ++i) {
+            /* check for memory-less node */
+            if (machine->numa_state->nodes[i].node_mem == 0) {
+                CPUState *cs;
+                int found = 0;
+                /* check for cpu-less node */
+                CPU_FOREACH(cs) {
+                    PowerPCCPU *cpu = POWERPC_CPU(cs);
+                    if (cpu->node_id == i) {
+                        found = 1;
+                        break;
+                    }
+                }
+                /* memory-less and cpu-less node */
+                if (!found) {
+                    error_report(
+"Memory-less/cpu-less nodes are not supported with FORM1 NUMA (node %d)", i);
+                    exit(EXIT_FAILURE);
+                }
+            }
+        }
+    }
+
+    if (!spapr_numa_is_symmetrical(machine)) {
+        error_report(
+"Asymmetrical NUMA topologies aren't supported in the pSeries machine using FORM1 NUMA");
+        exit(EXIT_FAILURE);
+    }
+}
+
 /*
  * Set NUMA machine state data based on FORM1 affinity semantics.
  */
@@ -250,12 +292,6 @@ static void spapr_numa_FORM1_affinity_init(SpaprMachineState *spapr,
         return;
     }
 
-    if (!spapr_numa_is_symmetrical(machine)) {
-        error_report("Asymmetrical NUMA topologies aren't supported "
-                     "in the pSeries machine");
-        exit(EXIT_FAILURE);
-    }
-
     spapr_numa_define_FORM1_domains(spapr);
 }
 
@@ -265,6 +301,11 @@ void spapr_numa_associativity_init(SpaprMachineState *spapr,
     spapr_numa_FORM1_affinity_init(spapr, machine);
 }
 
+void spapr_numa_associativity_check(SpaprMachineState *spapr)
+{
+    spapr_numa_FORM1_affinity_check(MACHINE(spapr));
+}
+
 void spapr_numa_write_associativity_dt(SpaprMachineState *spapr, void *fdt,
                                        int offset, int nodeid)
 {