[Qemu-devel] [PATCH 1/5] target-arm: Add ARM CPU feature parsing

[Greg Bellows]

Adds a CPU feature parsing function and assigns to the CPU class.  The only
feature added was "-aarch64" which disabled the AArch64 execution state on a
64-bit ARM CPU.

Also adds stripping of features from CPU model string in acquiring the ARM CPU
by name.

Signed-off-by: Greg Bellows <address@hidden>
---
 target-arm/cpu.c | 45 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index 285947f..f327dd7 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -514,13 +514,17 @@ static ObjectClass *arm_cpu_class_by_name(const char 
*cpu_model)
 {
     ObjectClass *oc;
     char *typename;
+    char *cpuname;
 
     if (!cpu_model) {
         return NULL;
     }
 
-    typename = g_strdup_printf("%s-" TYPE_ARM_CPU, cpu_model);
+    cpuname = g_strdup(cpu_model);
+    cpuname = strtok(cpuname, ",");
+    typename = g_strdup_printf("%s-" TYPE_ARM_CPU, cpuname);
     oc = object_class_by_name(typename);
+    g_free(cpuname);
     g_free(typename);
     if (!oc || !object_class_dynamic_cast(oc, TYPE_ARM_CPU) ||
         object_class_is_abstract(oc)) {
@@ -1163,6 +1167,44 @@ static Property arm_cpu_properties[] = {
     DEFINE_PROP_END_OF_LIST()
 };
 
+static void arm_cpu_parse_features(CPUState *cs, char *features,
+                                   Error **errp)
+{
+    ARMCPU *cpu = ARM_CPU(cs);
+    char *featurestr;
+
+    featurestr = features ? strtok(features, ",") : NULL;
+    while (featurestr) {
+        if (featurestr[0] == '-') {
+            if (!strcmp(featurestr+1, "aarch64")) {
+                /* If AArch64 is disabled then we need to unset the feature */
+                unset_feature(&cpu->env, ARM_FEATURE_AARCH64);
+            } else {
+                /* Everyting else is unsupported */
+                error_setg(errp, "unsupported CPU property '%s'",
+                           &featurestr[1]);
+                return;
+            }
+        } else if (featurestr[0] == '+') {
+            /* No '+' properties supported yet */
+            error_setg(errp, "unsupported CPU property '%s'",
+                       &featurestr[1]);
+            return;
+        } else if (g_strstr_len(featurestr, -1, "=")) {
+            /* No '=' properties supported yet */
+            char *prop = strtok(featurestr, "=");
+            error_setg(errp, "unsupported CPU property '%s'", prop);
+            return;
+        } else {
+            /* Everything else is a bad format */
+            error_setg(errp, "CPU property string '%s' not in format "
+                             "(+feature|-feature|feature=xyz)", featurestr);
+            return;
+        }
+        featurestr = strtok(NULL, ",");
+    }
+}
+
 static void arm_cpu_class_init(ObjectClass *oc, void *data)
 {
     ARMCPUClass *acc = ARM_CPU_CLASS(oc);
@@ -1183,6 +1225,7 @@ static void arm_cpu_class_init(ObjectClass *oc, void 
*data)
     cc->set_pc = arm_cpu_set_pc;
     cc->gdb_read_register = arm_cpu_gdb_read_register;
     cc->gdb_write_register = arm_cpu_gdb_write_register;
+    cc->parse_features = arm_cpu_parse_features;
 #ifdef CONFIG_USER_ONLY
     cc->handle_mmu_fault = arm_cpu_handle_mmu_fault;
 #else
-- 
1.8.3.2