target/i386/cpu: Mask off SGX/SGX_LC feature words for non-PC machine

Only PC machine supports SGX, so mask off SGX related feature words for
non-PC machine (microvm).

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20240730045544.2516284-5-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/i386/sgx-stub.c

@@ -32,6 +32,11 @@ void pc_machine_init_sgx_epc(PCMachineState *pcms)
     memset(&pcms->sgx_epc, 0, sizeof(SGXEPCState));
 }
 
+bool check_sgx_support(void)
+{
+    return false;
+}
+
 bool sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size)
 {
     return true;

hw/i386/sgx.c

@@ -266,6 +266,14 @@ void hmp_info_sgx(Monitor *mon, const QDict *qdict)
                    size);
 }
 
+bool check_sgx_support(void)
+{
+    if (!object_dynamic_cast(qdev_get_machine(), TYPE_PC_MACHINE)) {
+        return false;
+    }
+    return true;
+}
+
 bool sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size)
 {
     PCMachineState *pcms =

include/hw/i386/sgx-epc.h

@@ -58,6 +58,7 @@ typedef struct SGXEPCState {
     int nr_sections;
 } SGXEPCState;
 
+bool check_sgx_support(void);
 bool sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size);
 void sgx_epc_build_srat(GArray *table_data);
 

target/i386/cpu.c

@@ -6103,6 +6103,21 @@ uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, FeatureWord w)
         }
         break;
 
+    case FEAT_7_0_EBX:
+#ifndef CONFIG_USER_ONLY
+        if (!check_sgx_support()) {
+            unavail = CPUID_7_0_EBX_SGX;
+        }
+#endif
+        break;
+    case FEAT_7_0_ECX:
+#ifndef CONFIG_USER_ONLY
+        if (!check_sgx_support()) {
+            unavail = CPUID_7_0_ECX_SGX_LC;
+        }
+#endif
+        break;
+
     default:
         break;
     }