spapr: nested: keep nested-hv related code restricted to its API.

spapr_exit_nested and spapr_get_pate_nested_hv contains code which
is specific to nested-hv API. Isolating code flows based on API
helps extending it to be used with different API as well.

Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

hw/ppc/spapr.c

@@ -1421,7 +1421,11 @@ static bool spapr_get_pate(PPCVirtualHypervisor *vhyp, PowerPCCPU *cpu,
         entry->dw1 = spapr->patb_entry;
         return true;
     } else {
-        return spapr_get_pate_nested_hv(spapr, cpu, lpid, entry);
+        assert(spapr_nested_api(spapr));
+        if (spapr_nested_api(spapr) == NESTED_API_KVM_HV) {
+            return spapr_get_pate_nested_hv(spapr, cpu, lpid, entry);
+        }
+        return false;
     }
 }
 

hw/ppc/spapr_nested.c

@@ -11,11 +11,19 @@
 void spapr_nested_reset(SpaprMachineState *spapr)
 {
     if (spapr_get_cap(spapr, SPAPR_CAP_NESTED_KVM_HV)) {
+        spapr->nested.api = NESTED_API_KVM_HV;
         spapr_unregister_nested_hv();
         spapr_register_nested_hv();
+    } else {
+        spapr->nested.api = 0;
     }
 }
 
+uint8_t spapr_nested_api(SpaprMachineState *spapr)
+{
+    return spapr->nested.api;
+}
+
 #ifdef CONFIG_TCG
 
 bool spapr_get_pate_nested_hv(SpaprMachineState *spapr, PowerPCCPU *cpu,
@@ -310,7 +318,7 @@ static target_ulong h_enter_nested(PowerPCCPU *cpu,
     return env->gpr[3];
 }
 
-void spapr_exit_nested(PowerPCCPU *cpu, int excp)
+static void spapr_exit_nested_hv(PowerPCCPU *cpu, int excp)
 {
     CPUPPCState *env = &cpu->env;
     SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
@@ -322,8 +330,6 @@ void spapr_exit_nested(PowerPCCPU *cpu, int excp)
     struct kvmppc_pt_regs *regs;
     hwaddr len;
 
-    assert(spapr_cpu->in_nested);
-
     nested_save_state(&l2_state, cpu);
     hsrr0 = env->spr[SPR_HSRR0];
     hsrr1 = env->spr[SPR_HSRR1];
@@ -413,6 +419,19 @@ void spapr_exit_nested(PowerPCCPU *cpu, int excp)
     address_space_unmap(CPU(cpu)->as, regs, len, len, true);
 }
 
+void spapr_exit_nested(PowerPCCPU *cpu, int excp)
+{
+    SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
+    SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
+
+    assert(spapr_cpu->in_nested);
+    if (spapr_nested_api(spapr) == NESTED_API_KVM_HV) {
+        spapr_exit_nested_hv(cpu, excp);
+    } else {
+        g_assert_not_reached();
+    }
+}
+
 void spapr_register_nested_hv(void)
 {
     spapr_register_hypercall(KVMPPC_H_SET_PARTITION_TABLE, h_set_ptbl);

include/hw/ppc/spapr_nested.h

@@ -5,6 +5,8 @@
 
 typedef struct SpaprMachineStateNested {
     uint64_t ptcr;
+    uint8_t api;
+#define NESTED_API_KVM_HV  1
 } SpaprMachineStateNested;
 
 /*
@@ -103,4 +105,5 @@ void spapr_exit_nested(PowerPCCPU *cpu, int excp);
 typedef struct SpaprMachineState SpaprMachineState;
 bool spapr_get_pate_nested_hv(SpaprMachineState *spapr, PowerPCCPU *cpu,
                               target_ulong lpid, ppc_v3_pate_t *entry);
+uint8_t spapr_nested_api(SpaprMachineState *spapr);
 #endif /* HW_SPAPR_NESTED_H */