target/ppc/spapr_caps: Add new tristate cap safe_bounds_check

Add new tristate cap cap-sbbc to represent the speculation barrier
bounds checking capability.
Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>

hw/ppc/spapr.c

@@ -1792,6 +1792,7 @@ static const VMStateDescription vmstate_spapr = {
         &vmstate_spapr_cap_vsx,
         &vmstate_spapr_cap_dfp,
         &vmstate_spapr_cap_cfpc,
+        &vmstate_spapr_cap_sbbc,
         NULL
     }
 };
@@ -3883,6 +3884,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     smc->default_caps.caps[SPAPR_CAP_VSX] = SPAPR_CAP_ON;
     smc->default_caps.caps[SPAPR_CAP_DFP] = SPAPR_CAP_ON;
     smc->default_caps.caps[SPAPR_CAP_CFPC] = SPAPR_CAP_BROKEN;
+    smc->default_caps.caps[SPAPR_CAP_SBBC] = SPAPR_CAP_BROKEN;
     spapr_caps_add_properties(smc, &error_abort);
 }
 

hw/ppc/spapr_caps.c

@@ -191,6 +191,17 @@ static void cap_safe_cache_apply(sPAPRMachineState *spapr, uint8_t val,
     }
 }
 
+static void cap_safe_bounds_check_apply(sPAPRMachineState *spapr, uint8_t val,
+                                        Error **errp)
+{
+    if (tcg_enabled() && val) {
+        /* TODO - for now only allow broken for TCG */
+        error_setg(errp, "Requested safe bounds check capability level not supported by tcg, try a different value for cap-sbbc");
+    } else if (kvm_enabled() && (val > kvmppc_get_cap_safe_bounds_check())) {
+        error_setg(errp, "Requested safe bounds check capability level not supported by kvm, try a different value for cap-sbbc");
+    }
+}
+
 #define VALUE_DESC_TRISTATE     " (broken, workaround, fixed)"
 
 sPAPRCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
@@ -230,6 +241,15 @@ sPAPRCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
         .type = "string",
         .apply = cap_safe_cache_apply,
     },
+    [SPAPR_CAP_SBBC] = {
+        .name = "sbbc",
+        .description = "Speculation Barrier Bounds Checking" VALUE_DESC_TRISTATE,
+        .index = SPAPR_CAP_SBBC,
+        .get = spapr_cap_get_tristate,
+        .set = spapr_cap_set_tristate,
+        .type = "string",
+        .apply = cap_safe_bounds_check_apply,
+    },
 };
 
 static sPAPRCapabilities default_caps_with_cpu(sPAPRMachineState *spapr,
@@ -336,6 +356,7 @@ SPAPR_CAP_MIG_STATE(htm, HTM);
 SPAPR_CAP_MIG_STATE(vsx, VSX);
 SPAPR_CAP_MIG_STATE(dfp, DFP);
 SPAPR_CAP_MIG_STATE(cfpc, CFPC);
+SPAPR_CAP_MIG_STATE(sbbc, SBBC);
 
 void spapr_caps_reset(sPAPRMachineState *spapr)
 {

include/hw/ppc/spapr.h

@@ -62,8 +62,10 @@ typedef enum {
 #define SPAPR_CAP_DFP                   0x02
 /* Cache Flush on Privilege Change */
 #define SPAPR_CAP_CFPC                  0x03
+/* Speculation Barrier Bounds Checking */
+#define SPAPR_CAP_SBBC                  0x04
 /* Num Caps */
-#define SPAPR_CAP_NUM                   (SPAPR_CAP_CFPC + 1)
+#define SPAPR_CAP_NUM                   (SPAPR_CAP_SBBC + 1)
 
 /*
  * Capability Values
@@ -782,6 +784,7 @@ extern const VMStateDescription vmstate_spapr_cap_htm;
 extern const VMStateDescription vmstate_spapr_cap_vsx;
 extern const VMStateDescription vmstate_spapr_cap_dfp;
 extern const VMStateDescription vmstate_spapr_cap_cfpc;
+extern const VMStateDescription vmstate_spapr_cap_sbbc;
 
 static inline uint8_t spapr_get_cap(sPAPRMachineState *spapr, int cap)
 {