target/ppc: Allow cpu compatiblity checks based on type, not instance

ppc_check_compat() is used in a number of places to check if a cpu object
supports a certain compatiblity mode, subject to various constraints.

It takes a PowerPCCPU *, however it really only depends on the cpu's class.
We have upcoming cases where it would be useful to make compatibility
checks before we fully instantiate the cpu objects.

ppc_type_check_compat() will now make an equivalent check, but based on a
CPU's QOM typename instead of an instantiated CPU object.

We make use of the new interface in several places in spapr, where we're
essentially making a global check, rather than one specific to a particular
cpu.  This avoids some ugly uses of first_cpu to grab a "representative"
instance.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>

2 files changed, 25 insertions, 6 deletions

diff --git a/target/ppc/compat.c b/target/ppc/compat.c
index 807c906f68..7de4bf3122 100644
--- a/target/ppc/compat.c
+++ b/target/ppc/compat.c
@@ -105,17 +105,13 @@ static const CompatInfo *compat_by_pvr(uint32_t pvr)
     return NULL;
 }
 
-bool ppc_check_compat(PowerPCCPU *cpu, uint32_t compat_pvr,
-                      uint32_t min_compat_pvr, uint32_t max_compat_pvr)
+static bool pcc_compat(PowerPCCPUClass *pcc, uint32_t compat_pvr,
+                       uint32_t min_compat_pvr, uint32_t max_compat_pvr)
 {
-    PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
     const CompatInfo *compat = compat_by_pvr(compat_pvr);
     const CompatInfo *min = compat_by_pvr(min_compat_pvr);
     const CompatInfo *max = compat_by_pvr(max_compat_pvr);
 
-#if !defined(CONFIG_USER_ONLY)
-    g_assert(cpu->vhyp);
-#endif
     g_assert(!min_compat_pvr || min);
     g_assert(!max_compat_pvr || max);
 
@@ -134,6 +130,25 @@ bool ppc_check_compat(PowerPCCPU *cpu, uint32_t compat_pvr,
     return true;
 }
 
+bool ppc_check_compat(PowerPCCPU *cpu, uint32_t compat_pvr,
+                      uint32_t min_compat_pvr, uint32_t max_compat_pvr)
+{
+    PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
+
+#if !defined(CONFIG_USER_ONLY)
+    g_assert(cpu->vhyp);
+#endif
+
+    return pcc_compat(pcc, compat_pvr, min_compat_pvr, max_compat_pvr);
+}
+
+bool ppc_type_check_compat(const char *cputype, uint32_t compat_pvr,
+                           uint32_t min_compat_pvr, uint32_t max_compat_pvr)
+{
+    PowerPCCPUClass *pcc = POWERPC_CPU_CLASS(object_class_by_name(cputype));
+    return pcc_compat(pcc, compat_pvr, min_compat_pvr, max_compat_pvr);
+}
+
 void ppc_set_compat(PowerPCCPU *cpu, uint32_t compat_pvr, Error **errp)
 {
     const CompatInfo *compat = compat_by_pvr(compat_pvr);
diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 874da6efbc..c7f3fb6b73 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -1369,7 +1369,11 @@ static inline int cpu_mmu_index (CPUPPCState *env, bool ifetch)
 #if defined(TARGET_PPC64)
 bool ppc_check_compat(PowerPCCPU *cpu, uint32_t compat_pvr,
                       uint32_t min_compat_pvr, uint32_t max_compat_pvr);
+bool ppc_type_check_compat(const char *cputype, uint32_t compat_pvr,
+                           uint32_t min_compat_pvr, uint32_t max_compat_pvr);
+
 void ppc_set_compat(PowerPCCPU *cpu, uint32_t compat_pvr, Error **errp);
+
 #if !defined(CONFIG_USER_ONLY)
 void ppc_set_compat_all(uint32_t compat_pvr, Error **errp);
 #endif