[PATCH 5/5] qmp: Added qemu-ebpf-rss-path command.

[Andrew Melnychenko <andrew@daynix.com>]

New qmp command to query ebpf helper.
It's crucial that qemu and helper are in sync and in touch.
Technically helper should pass eBPF fds that qemu may accept.
And different qemu's builds may have different eBPF programs and helpers.
Qemu returns helper that should "fit" to virtio-net.

Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
---
 monitor/qmp-cmds.c | 32 ++++++++++++++++++++++++++++++++
 qapi/misc.json     | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c
index f7d64a6457..c042ab5466 100644
--- a/monitor/qmp-cmds.c
+++ b/monitor/qmp-cmds.c
@@ -40,6 +40,7 @@
 #include "qapi/qmp/qerror.h"
 #include "hw/mem/memory-device.h"
 #include "hw/acpi/acpi_dev_interface.h"
+#include "qemu-helper-stamp-utils.h"
 
 NameInfo *qmp_query_name(Error **errp)
 {
@@ -351,3 +352,34 @@ void qmp_display_reload(DisplayReloadOptions *arg, Error **errp)
         abort();
     }
 }
+
+HelperPathList *qmp_query_helper_paths(Error **errp)
+{
+    HelperPathList *ret = NULL;
+    struct {
+        const char *helper;
+        bool check_stamp;
+    } helpers_list[] = {
+#ifdef CONFIG_EBPF
+        { "qemu-ebpf-rss-helper", true },
+#endif
+        { "qemu-pr-helper", false },
+        { "qemu-bridge-helper", false },
+        { NULL, false },
+    }, *helper_iter;
+    helper_iter = helpers_list;
+
+    for (; helper_iter->helper != NULL; ++helper_iter) {
+        char *path = qemu_find_helper(helper_iter->helper,
+                                      helper_iter->check_stamp);
+        if (path) {
+            HelperPath *helper = g_new0(HelperPath, 1);
+            helper->name = g_strdup(helper_iter->helper);
+            helper->path = path;
+
+            QAPI_LIST_PREPEND(ret, helper);
+        }
+    }
+
+    return ret;
+}
diff --git a/qapi/misc.json b/qapi/misc.json
index 156f98203e..9aaf8fbcca 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -519,3 +519,36 @@
  'data': { '*option': 'str' },
  'returns': ['CommandLineOptionInfo'],
  'allow-preconfig': true }
+
+##
+# @HelperPath:
+#
+# Name of the helper and binary location.
+##
+{ 'struct': 'HelperPath',
+  'data': {'name': 'str', 'path': 'str'} }
+
+##
+# @query-helper-paths:
+#
+# Query helper paths. Initially, this command was added for
+# qemu-ebpf-rss-helper. The qemu would check "the stamp" and
+# returns proper helper.
+#
+# Returns: list of object that contains name and path for helper.
+#
+# Since: 6.1
+#
+# Example:
+#
+# -> { "execute": "query-helper-paths" }
+# <- { "return": [
+#        {
+#          "name": "qemu-ebpf-rss-helper",
+#          "path": "/usr/local/libexec/qemu-ebpf-rss-helper"
+#        }
+#      ]
+#    }
+#
+##
+{ 'command': 'query-helper-paths', 'returns': ['HelperPath'] }
-- 
2.31.1