[Qemu-devel] [RFC PATCH] target-ppc: Register CPU class per family only when needed

[Alexey Kardashevskiy <aik@ozlabs.ru>]

At the moment when running in KVM mode, QEMU registers "host" class to
match the current CPU PVR value. It also registers another CPU class
with a CPU family name os if we run QEMU on POWER7 machine, "host" and
"POWER7" classes are created, this way we can always use "-cpu POWER7"
on the actual POWER7 machine.

The existing code uses DeviceClass::desc field of the CPU class as
a source for the class name; it was pointed out that it is wrong to use
user-visible string as a type name.

This adds a common CPU class name into PowerPCCPUClass struct.
This makes registration of a CPU named after the family conditional -
PowerPCCPUClass::common_cpu_name has to be non-zero. Only POWER7/POWER8
families have this field initialized by now.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 target-ppc/cpu-qom.h        |  1 +
 target-ppc/kvm.c            | 11 ++++++-----
 target-ppc/translate_init.c |  2 ++
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/target-ppc/cpu-qom.h b/target-ppc/cpu-qom.h
index 6967a80..4b471d7 100644
--- a/target-ppc/cpu-qom.h
+++ b/target-ppc/cpu-qom.h
@@ -55,6 +55,7 @@ typedef struct PowerPCCPUClass {
     DeviceRealize parent_realize;
     void (*parent_reset)(CPUState *cpu);
 
+    const char *common_cpu_name;
     uint32_t pvr;
     bool (*pvr_match)(struct PowerPCCPUClass *pcc, uint32_t pvr);
     uint64_t pcr_mask;
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index b479471..3f2df65 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -2221,7 +2221,6 @@ static int kvm_ppc_register_host_cpu_type(void)
     };
     uint32_t host_pvr = mfpvr();
     PowerPCCPUClass *pvr_pcc;
-    DeviceClass *dc;
 
     pvr_pcc = ppc_cpu_class_by_pvr(host_pvr);
     if (pvr_pcc == NULL) {
@@ -2235,10 +2234,12 @@ static int kvm_ppc_register_host_cpu_type(void)
 
     /* Register generic family CPU class for a family */
     pvr_pcc = ppc_cpu_get_family_class(pvr_pcc);
-    dc = DEVICE_CLASS(pvr_pcc);
-    type_info.parent = object_class_get_name(OBJECT_CLASS(pvr_pcc));
-    type_info.name = g_strdup_printf("%s-"TYPE_POWERPC_CPU, dc->desc);
-    type_register(&type_info);
+    if (pvr_pcc->common_cpu_name) {
+        type_info.parent = object_class_get_name(OBJECT_CLASS(pvr_pcc));
+        type_info.name = g_strdup_printf("%s-"TYPE_POWERPC_CPU,
+                                         pvr_pcc->common_cpu_name);
+        type_register(&type_info);
+    }
 
     return 0;
 }
diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
index df1a62c..3d0be66 100644
--- a/target-ppc/translate_init.c
+++ b/target-ppc/translate_init.c
@@ -8117,6 +8117,7 @@ POWERPC_FAMILY(POWER7)(ObjectClass *oc, void *data)
     dc->fw_name = "PowerPC,POWER7";
     dc->desc = "POWER7";
     dc->props = powerpc_servercpu_properties;
+    pcc->common_cpu_name = "POWER7";
     pcc->pvr_match = ppc_pvr_match_power7;
     pcc->pcr_mask = PCR_COMPAT_2_05 | PCR_COMPAT_2_06;
     pcc->init_proc = init_proc_POWER7;
@@ -8193,6 +8194,7 @@ POWERPC_FAMILY(POWER8)(ObjectClass *oc, void *data)
     dc->fw_name = "PowerPC,POWER8";
     dc->desc = "POWER8";
     dc->props = powerpc_servercpu_properties;
+    pcc->common_cpu_name = "POWER8";
     pcc->pvr_match = ppc_pvr_match_power8;
     pcc->pcr_mask = PCR_COMPAT_2_05 | PCR_COMPAT_2_06;
     pcc->init_proc = init_proc_POWER8;
-- 
2.0.0