From 933bf632d65e1e6a4990da0a562c797c055a184b Mon Sep 17 00:00:00 2001
From: Konrad Sztyber <konrad.sztyber@intel.com>
Date: Wed, 6 Nov 2019 10:06:14 +0100
Subject: [PATCH] event/vmd: write_config_json support

This patch adds support for saving VMD subsystem's configuration to a
JSON formatted file.  It allows saving and then loading configuration
with VMD enabled without having to send the `enable_vmd` RPC.

Change-Id: I59b380ec1e1f25f60f45d2363724ed7ac78c365c
Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/473405
Community-CI: Broadcom SPDK FC-NVMe CI <spdk-ci.pdl@broadcom.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
---
 module/event/subsystems/vmd/vmd.c | 26 +++++++++++++++++++++++---
 test/json_config/clear_config.py  |  4 ++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/module/event/subsystems/vmd/vmd.c b/module/event/subsystems/vmd/vmd.c
index cf49960bf..49e3f4a7a 100644
--- a/module/event/subsystems/vmd/vmd.c
+++ b/module/event/subsystems/vmd/vmd.c
@@ -42,6 +42,7 @@
 #include "event_vmd.h"
 
 static struct spdk_poller *g_hotplug_poller;
+static bool g_enabled;
 
 static int
 vmd_hotplug_monitor(void *ctx)
@@ -54,8 +55,7 @@ vmd_subsystem_init(void)
 {
 	int rc;
 
-	/* If the poller is registered, the initialization already took place */
-	if (g_hotplug_poller != NULL) {
+	if (g_enabled) {
 		SPDK_ERRLOG("The initialization has already been performed\n");
 		return -EBUSY;
 	}
@@ -66,12 +66,16 @@ vmd_subsystem_init(void)
 		return rc;
 	}
 
+	assert(g_hotplug_poller == NULL);
+
 	g_hotplug_poller = spdk_poller_register(vmd_hotplug_monitor, NULL, 1000000ULL);
 	if (g_hotplug_poller == NULL) {
 		SPDK_ERRLOG("Failed to register hotplug monitor poller\n");
 		return -ENOMEM;
 	}
 
+	g_enabled = true;
+
 	return 0;
 }
 
@@ -99,12 +103,28 @@ spdk_vmd_subsystem_fini(void)
 	spdk_subsystem_fini_next();
 }
 
+static void
+spdk_vmd_write_config_json(struct spdk_json_write_ctx *w)
+{
+	spdk_json_write_array_begin(w);
+
+	if (g_enabled) {
+		spdk_json_write_object_begin(w);
+		spdk_json_write_named_string(w, "method", "enable_vmd");
+		spdk_json_write_named_object_begin(w, "params");
+		spdk_json_write_object_end(w);
+		spdk_json_write_object_end(w);
+	}
+
+	spdk_json_write_array_end(w);
+}
+
 static struct spdk_subsystem g_spdk_subsystem_vmd = {
 	.name = "vmd",
 	.init = spdk_vmd_subsystem_init,
 	.fini = spdk_vmd_subsystem_fini,
 	.config = NULL,
-	.write_config_json = NULL,
+	.write_config_json = spdk_vmd_write_config_json,
 };
 
 SPDK_SUBSYSTEM_REGISTER(g_spdk_subsystem_vmd);
diff --git a/test/json_config/clear_config.py b/test/json_config/clear_config.py
index 5328e6dc1..c40151e75 100755
--- a/test/json_config/clear_config.py
+++ b/test/json_config/clear_config.py
@@ -153,6 +153,10 @@ def clear_vhost_subsystem(args, vhost_config):
                 args.client.call("vhost_delete_controller", {'ctrlr': vhost['params']['ctrlr']})
 
 
+def clear_vmd_subsystem(args, vmd_config):
+    pass
+
+
 def call_test_cmd(func):
     def rpc_test_cmd(*args, **kwargs):
         try: