monitor: generalize query-mshv/"info mshv" to query-accelerators/"info accelerators"

The recently-introduced query-mshv command is a duplicate of query-kvm,
and neither provides a full view of which accelerators are supported
by a particular binary of QEMU and which is in use.

KVM was the first accelerator added to QEMU, predating QOM and TYPE_ACCEL,
so it got a pass.  But now, instead of adding a badly designed copy, solve
the problem completely for all accelerators with a command that provides
the whole picture:

    >> {"execute": "query-accelerators"}
    << {"return": {"enabled": "tcg", "present": ["kvm", "mshv", "qtest", "tcg", "xen"]}}

Cc: Praveen K Paladugu <prapal@microsoft.com>
Cc: Magnus Kulke <magnuskulke@linux.microsoft.com>
Suggested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hmp-commands-info.hx

@@ -308,16 +308,21 @@ SRST
 ERST
 
     {
-        .name       = "mshv",
+        .name       = "accelerators",
         .args_type  = "",
         .params     = "",
-        .help       = "show MSHV information",
-        .cmd        = hmp_info_mshv,
+        .help       = "show present and enabled information",
+        .cmd        = hmp_info_accelerators,
     },
 
 SRST
-  ``info mshv``
-    Show MSHV information.
+  ``info accelerators``
+    Show which accelerators are compiled into a QEMU binary, and what accelerator
+    is in use. For example::
+
+        kvm qtest [tcg]
+
+    indicates that TCG in use, and that KVM and qtest are also available.
 ERST
 
     {

hw/core/machine-hmp-cmds.c

@@ -163,19 +163,22 @@ void hmp_info_kvm(Monitor *mon, const QDict *qdict)
     qapi_free_KvmInfo(info);
 }
 
-void hmp_info_mshv(Monitor *mon, const QDict *qdict)
+void hmp_info_accelerators(Monitor *mon, const QDict *qdict)
 {
-    MshvInfo *info;
+    AcceleratorInfo *info;
+    AcceleratorList *accel;
 
-    info = qmp_query_mshv(NULL);
-    monitor_printf(mon, "mshv support: ");
-    if (info->present) {
-        monitor_printf(mon, "%s\n", info->enabled ? "enabled" : "disabled");
-    } else {
-        monitor_printf(mon, "not compiled\n");
+    info = qmp_query_accelerators(NULL);
+    for (accel = info->present; accel; accel = accel->next) {
+        char trail = accel->next ? ' ' : '\n';
+        if (info->enabled == accel->value) {
+            monitor_printf(mon, "[%s]%c", Accelerator_str(accel->value), trail);
+        } else {
+            monitor_printf(mon, "%s%c", Accelerator_str(accel->value), trail);
+        }
     }
 
-    qapi_free_MshvInfo(info);
+    qapi_free_AcceleratorInfo(info);
 }
 
 void hmp_info_uuid(Monitor *mon, const QDict *qdict)

hw/core/machine-qmp-cmds.c

@@ -31,15 +31,25 @@
 #include <sys/stat.h>
 
 /*
- * QMP query for MSHV
+ * QMP query for enabled and present accelerators
  */
-MshvInfo *qmp_query_mshv(Error **errp)
+AcceleratorInfo *qmp_query_accelerators(Error **errp)
 {
-    MshvInfo *info = g_malloc0(sizeof(*info));
+    AcceleratorInfo *info = g_malloc0(sizeof(*info));
+    AccelClass *current_class = ACCEL_GET_CLASS(current_accel());
+    int i;
 
-    info->enabled = mshv_enabled();
-    info->present = accel_find("mshv");
+    for (i = ACCELERATOR__MAX; i-- > 0; ) {
+        const char *s = Accelerator_str(i);
+        AccelClass *this_class = accel_find(s);
 
+        if (this_class) {
+            QAPI_LIST_PREPEND(info->present, i);
+            if (this_class == current_class) {
+                info->enabled = i;
+            }
+        }
+    }
     return info;
 }
 

include/monitor/hmp.h

@@ -24,7 +24,7 @@ strList *hmp_split_at_comma(const char *str);
 void hmp_info_name(Monitor *mon, const QDict *qdict);
 void hmp_info_version(Monitor *mon, const QDict *qdict);
 void hmp_info_kvm(Monitor *mon, const QDict *qdict);
-void hmp_info_mshv(Monitor *mon, const QDict *qdict);
+void hmp_info_accelerators(Monitor *mon, const QDict *qdict);
 void hmp_info_status(Monitor *mon, const QDict *qdict);
 void hmp_info_uuid(Monitor *mon, const QDict *qdict);
 void hmp_info_chardev(Monitor *mon, const QDict *qdict);

qapi/accelerator.json

@@ -56,30 +56,55 @@
   'features': [ 'unstable' ] }
 
 ##
-# @MshvInfo:
+# @Accelerator:
 #
 # Information about support for MSHV acceleration
 #
-# @enabled: true if MSHV acceleration is active
+# @hvf: Apple Hypervisor.framework
 #
-# @present: true if MSHV acceleration is built into this executable
+# @kvm: KVM
+#
+# @mshv: Hyper-V
+#
+# @nvmm: NetBSD NVMM
+#
+# @qtest: QTest (dummy accelerator)
+#
+# @tcg: TCG (dynamic translation)
+#
+# @whpx: Windows Hypervisor Platform
+#
+# @xen: Xen
 #
 # Since: 10.2.0
 ##
-{ 'struct': 'MshvInfo', 'data': {'enabled': 'bool', 'present': 'bool'} }
+{ 'enum': 'Accelerator', 'data': ['hvf', 'kvm', 'mshv', 'nvmm', 'qtest', 'tcg', 'whpx', 'xen'] }
 
 ##
-# @query-mshv:
+# @AcceleratorInfo:
 #
-# Return information about MSHV acceleration
+# Information about support for various accelerators
 #
-# Returns: @MshvInfo
+# @enabled: the accelerator that is in use
 #
-# Since: 10.0.92
+# @present: the list of accelerators that are built into this executable
+#
+# Since: 10.2.0
+##
+{ 'struct': 'AcceleratorInfo', 'data': {'enabled': 'Accelerator', 'present': ['Accelerator']} }
+
+##
+# @query-accelerators:
+#
+# Return information about accelerators
+#
+# Returns: @AcceleratorInfo
+#
+# Since: 10.2.0
 #
 # .. qmp-example::
 #
-#     -> { "execute": "query-mshv" }
-#     <- { "return": { "enabled": true, "present": true } }
+#     -> { "execute": "query-accelerators" }
+#     <- { "return": { "enabled": "mshv", "present": ["kvm", "mshv", "qtest", "tcg"] } }
 ##
-{ 'command': 'query-mshv', 'returns': 'MshvInfo' }
+{ 'command': 'query-accelerators', 'returns': 'AcceleratorInfo' }