[PATCH v2 5/6] qmp: Added new command to retrieve eBPF blob.

[Andrew Melnychenko]

Added command "request-ebpf". This command returns
eBPF program encoded base64. The program taken from the
skeleton and essentially is an ELF object that can be
loaded in the future with libbpf.

Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
---
 monitor/qmp-cmds.c | 16 ++++++++++++++++
 qapi/misc.json     | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c
index b0f948d3376..259bc87ccb1 100644
--- a/monitor/qmp-cmds.c
+++ b/monitor/qmp-cmds.c
@@ -32,6 +32,7 @@
 #include "hw/mem/memory-device.h"
 #include "hw/intc/intc.h"
 #include "hw/rdma/rdma.h"
+#include "ebpf/ebpf.h"
 
 NameInfo *qmp_query_name(Error **errp)
 {
@@ -209,3 +210,18 @@ static void __attribute__((__constructor__)) 
monitor_init_qmp_commands(void)
                          qmp_marshal_qmp_capabilities,
                          QCO_ALLOW_PRECONFIG, 0);
 }
+
+EbpfObject *qmp_request_ebpf(EbpfProgramID id, Error **errp)
+{
+    EbpfObject *ret = NULL;
+    size_t size = 0;
+    const void *data = ebpf_find_binary_by_id(id, &size, errp);
+    if (!data) {
+        return NULL;
+    }
+
+    ret = g_new0(EbpfObject, 1);
+    ret->object = g_base64_encode(data, size);
+
+    return ret;
+}
diff --git a/qapi/misc.json b/qapi/misc.json
index 6ddd16ea283..e96dac8482b 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -618,3 +618,41 @@
 { 'event': 'VFU_CLIENT_HANGUP',
   'data': { 'vfu-id': 'str', 'vfu-qom-path': 'str',
             'dev-id': 'str', 'dev-qom-path': 'str' } }
+
+##
+# @EbpfObject:
+#
+# Structure that holds eBPF ELF object encoded in base64.
+#
+# Since: 8.1
+#
+##
+{ 'struct': 'EbpfObject',
+  'data': {'object': 'str'} }
+
+##
+# @EbpfProgramID:
+#
+# An enumeration of the eBPF programs. Currently, only RSS is presented.
+#
+# Since: 8.1
+##
+{ 'enum': 'EbpfProgramID',
+  'data': [ { 'name': 'rss', 'if': 'CONFIG_EBPF' } ] }
+
+##
+# @request-ebpf:
+#
+# Function returns eBPF object that can be loaded with libbpf.
+# Management applications (g.e. libvirt) may load it and pass file
+# descriptors to QEMU. Which allows running QEMU without BPF capabilities.
+#
+# Returns: RSS eBPF object encoded in base64.
+#
+# Since: 8.1
+#
+##
+{ 'command': 'request-ebpf',
+  'data': { 'id': 'EbpfProgramID' },
+  'returns': 'EbpfObject' }
+
-- 
2.39.1