ppc/pnv: use class attribute to limit SMT threads for different machines

Use a class attribute to specify the number of SMT threads per core
permitted for different machines, 8 for powernv8 and 4 for powernv9/10.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 91ff1be21f..a84e0e0e30 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -899,6 +899,7 @@ static void pnv_init(MachineState *machine)
     PnvMachineState *pnv = PNV_MACHINE(machine);
     MachineClass *mc = MACHINE_GET_CLASS(machine);
     PnvMachineClass *pmc = PNV_MACHINE_GET_CLASS(machine);
+    int max_smt_threads = pmc->max_smt_threads;
     char *fw_filename;
     long fw_size;
     uint64_t chip_ram_start = 0;
@@ -997,17 +998,19 @@ static void pnv_init(MachineState *machine)
     pnv->num_chips =
         machine->smp.max_cpus / (machine->smp.cores * machine->smp.threads);
 
-    if (machine->smp.threads > 8) {
-        error_report("Cannot support more than 8 threads/core "
-                     "on a powernv machine");
+    if (machine->smp.threads > max_smt_threads) {
+        error_report("Cannot support more than %d threads/core "
+                     "on %s machine", max_smt_threads, mc->desc);
         exit(1);
     }
+
     if (!is_power_of_2(machine->smp.threads)) {
         error_report("Cannot support %d threads/core on a powernv"
                      "machine because it must be a power of 2",
                      machine->smp.threads);
         exit(1);
     }
+
     /*
      * TODO: should we decide on how many chips we can create based
      * on #cores and Venice vs. Murano vs. Naples chip type etc...,
@@ -2490,6 +2493,7 @@ static void pnv_machine_power8_class_init(ObjectClass *oc, void *data)
 
     pmc->compat = compat;
     pmc->compat_size = sizeof(compat);
+    pmc->max_smt_threads = 8;
 
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_PNV_PHB);
 }
@@ -2514,6 +2518,7 @@ static void pnv_machine_power9_class_init(ObjectClass *oc, void *data)
 
     pmc->compat = compat;
     pmc->compat_size = sizeof(compat);
+    pmc->max_smt_threads = 4;
     pmc->dt_power_mgt = pnv_dt_power_mgt;
 
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_PNV_PHB);
@@ -2538,6 +2543,7 @@ static void pnv_machine_p10_common_class_init(ObjectClass *oc, void *data)
 
     pmc->compat = compat;
     pmc->compat_size = sizeof(compat);
+    pmc->max_smt_threads = 4;
     pmc->dt_power_mgt = pnv_dt_power_mgt;
 
     xfc->match_nvt = pnv10_xive_match_nvt;