[Qemu-devel] [PATCH v4 03/20] ppc/pnv: add a core mask to PnvChip

["Cédric Le Goater" <clg@kaod.org>]

This will be used to build real HW ids for the cores and enforce some
limits on the available cores per chip.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
---

 Changes since v3 :

 - reworked pnv_chip_core_sanitize() to return errors and to check the
   maximum of cores against the instance cores_mask
  
 Changes since v2 :

 - added POWER9 support
 - removed cores_max 
 - introduces a pnv_chip_core_sanitize() helper to check the core
   ids_mask and the maximum number of cores

 hw/ppc/pnv.c         | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 include/hw/ppc/pnv.h |  4 +++
 2 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 08f72dbdca97..fc930be94f53 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -227,11 +227,44 @@ static void ppc_powernv_init(MachineState *machine)
         snprintf(chip_name, sizeof(chip_name), "chip[%d]", CHIP_HWID(i));
         object_property_add_child(OBJECT(pnv), chip_name, chip, &error_fatal);
         object_property_set_int(chip, CHIP_HWID(i), "chip-id", &error_fatal);
+        object_property_set_int(chip, smp_cores, "nr-cores", &error_fatal);
+        /*
+         * We could customize cores_mask for the chip here. May be
+         * using a powernv machine property, like 'num-chips'. Let the
+         * chip choose the default for now.
+         */
+        object_property_set_int(chip, 0x0, "cores-mask", &error_fatal);
         object_property_set_bool(chip, true, "realized", &error_fatal);
     }
     g_free(chip_typename);
 }
 
+/* Allowed core identifiers on a POWER8 Processor Chip :
+ *
+ * <EX0 reserved>
+ *  EX1  - Venice only
+ *  EX2  - Venice only
+ *  EX3  - Venice only
+ *  EX4
+ *  EX5
+ *  EX6
+ * <EX7,8 reserved> <reserved>
+ *  EX9  - Venice only
+ *  EX10 - Venice only
+ *  EX11 - Venice only
+ *  EX12
+ *  EX13
+ *  EX14
+ * <EX15 reserved>
+ */
+#define POWER8E_CORE_MASK  (0x7070ull)
+#define POWER8_CORE_MASK   (0x7e7eull)
+
+/*
+ * POWER9 has 24 cores, ids starting at 0x20
+ */
+#define POWER9_CORE_MASK   (0xffffff00000000ull)
+
 static void pnv_chip_power8e_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
@@ -240,6 +273,7 @@ static void pnv_chip_power8e_class_init(ObjectClass *klass, void *data)
     k->cpu_model = "POWER8E";
     k->chip_type = PNV_CHIP_POWER8E;
     k->chip_cfam_id = 0x221ef04980000000ull;  /* P8 Murano DD2.1 */
+    k->cores_mask = POWER8E_CORE_MASK;
     dc->desc = "PowerNV Chip POWER8E";
 }
 
@@ -258,6 +292,7 @@ static void pnv_chip_power8_class_init(ObjectClass *klass, void *data)
     k->cpu_model = "POWER8";
     k->chip_type = PNV_CHIP_POWER8;
     k->chip_cfam_id = 0x220ea04980000000ull; /* P8 Venice DD2.0 */
+    k->cores_mask = POWER8_CORE_MASK;
     dc->desc = "PowerNV Chip POWER8";
 }
 
@@ -276,6 +311,7 @@ static void pnv_chip_power8nvl_class_init(ObjectClass *klass, void *data)
     k->cpu_model = "POWER8NVL";
     k->chip_type = PNV_CHIP_POWER8NVL;
     k->chip_cfam_id = 0x120d304980000000ull;  /* P8 Naples DD1.0 */
+    k->cores_mask = POWER8_CORE_MASK;
     dc->desc = "PowerNV Chip POWER8NVL";
 }
 
@@ -294,6 +330,7 @@ static void pnv_chip_power9_class_init(ObjectClass *klass, void *data)
     k->cpu_model = "POWER9";
     k->chip_type = PNV_CHIP_POWER9;
     k->chip_cfam_id = 0x100d104980000000ull; /* P9 Nimbus DD1.0 */
+    k->cores_mask = POWER9_CORE_MASK;
     dc->desc = "PowerNV Chip POWER9";
 }
 
@@ -304,13 +341,52 @@ static const TypeInfo pnv_chip_power9_info = {
     .class_init    = pnv_chip_power9_class_init,
 };
 
+static void pnv_chip_core_sanitize(PnvChip *chip, Error **errp)
+{
+    PnvChipClass *pcc = PNV_CHIP_GET_CLASS(chip);
+    int cores_max;
+
+    /*
+     * No custom mask for this chip, let's use the default one from *
+     * the chip class
+     */
+    if (!chip->cores_mask) {
+        chip->cores_mask = pcc->cores_mask;
+    }
+
+    /* filter alien core ids ! some are reserved */
+    if ((chip->cores_mask & pcc->cores_mask) != chip->cores_mask) {
+        error_setg(errp, "warning: invalid core mask for chip !");
+        return;
+    }
+    chip->cores_mask &= pcc->cores_mask;
+
+    /* now that we have a sane layout, let check the number of cores */
+    cores_max = hweight_long(chip->cores_mask);
+    if (chip->nr_cores > cores_max) {
+        error_setg(errp, "warning: too many cores for chip ! Limit is %d",
+                   cores_max);
+        return;
+    }
+}
+
 static void pnv_chip_realize(DeviceState *dev, Error **errp)
 {
-    /* left purposely empty */
+    PnvChip *chip = PNV_CHIP(dev);
+    Error *error = NULL;
+
+    /* Early checks on the core settings */
+    pnv_chip_core_sanitize(chip, &error);
+    if (error) {
+        error_propagate(errp, error);
+        return;
+    }
 }
 
 static Property pnv_chip_properties[] = {
     DEFINE_PROP_UINT32("chip-id", PnvChip, chip_id, 0),
+    DEFINE_PROP_UINT32("nr-cores", PnvChip, nr_cores, 1),
+    DEFINE_PROP_UINT64("cores-mask", PnvChip, cores_mask, 0x0),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/ppc/pnv.h b/include/hw/ppc/pnv.h
index da543ed81636..2c225c928974 100644
--- a/include/hw/ppc/pnv.h
+++ b/include/hw/ppc/pnv.h
@@ -42,6 +42,9 @@ typedef struct PnvChip {
 
     /*< public >*/
     uint32_t     chip_id;
+
+    uint32_t  nr_cores;
+    uint64_t  cores_mask;
 } PnvChip;
 
 typedef struct PnvChipClass {
@@ -52,6 +55,7 @@ typedef struct PnvChipClass {
     const char *cpu_model;
     PnvChipType  chip_type;
     uint64_t     chip_cfam_id;
+    uint64_t     cores_mask;
 } PnvChipClass;
 
 #define TYPE_PNV_CHIP_POWER8E TYPE_PNV_CHIP "-POWER8E"
-- 
2.7.4