diff --git a/vp/src/core/common/gdb-mc/gdb_server.cpp b/vp/src/core/common/gdb-mc/gdb_server.cpp
index e6fc1e637..c8a32b7f5 100644
--- a/vp/src/core/common/gdb-mc/gdb_server.cpp
+++ b/vp/src/core/common/gdb-mc/gdb_server.cpp
@@ -137,9 +137,11 @@ void GDBServer::exec_thread(thread_func fn, char op) {
 		fn(thread);
 }
 
-std::vector<debug_target_if *> GDBServer::run_threads(int id, bool single) {
+std::vector<debug_target_if *> GDBServer::run_threads(std::vector<debug_target_if *> hartsrun, bool single) {
+	if (hartsrun.empty()) {
+		return hartsrun;
+	}
 	this->single_run = single;
-	std::vector<debug_target_if *> hartsrun = get_threads(id);
 
 	/* invoke all selected harts */
 	sc_core::sc_event_or_list allharts;
diff --git a/vp/src/core/common/gdb-mc/gdb_server.h b/vp/src/core/common/gdb-mc/gdb_server.h
index eaf26c448..a8b5461af 100644
--- a/vp/src/core/common/gdb-mc/gdb_server.h
+++ b/vp/src/core/common/gdb-mc/gdb_server.h
@@ -87,7 +87,7 @@ SC_MODULE(GDBServer) {
 	std::vector<debug_target_if *> get_threads(int);
 	uint64_t translate_addr(debug_target_if *, uint64_t, MemoryAccessType type);
 	void exec_thread(thread_func, char = 'g');
-	std::vector<debug_target_if *> run_threads(int, bool = false);
+	std::vector<debug_target_if *> run_threads(std::vector<debug_target_if *>, bool = false);
 	void writeall(int, char *, size_t);
 	void send_packet(int, const char *, gdb_kind_t = GDB_KIND_PACKET);
 	void retransmit(int);
diff --git a/vp/src/core/common/gdb-mc/handler.cpp b/vp/src/core/common/gdb-mc/handler.cpp
index 2ba72980a..c55d88f35 100644
--- a/vp/src/core/common/gdb-mc/handler.cpp
+++ b/vp/src/core/common/gdb-mc/handler.cpp
@@ -208,6 +208,7 @@ void GDBServer::vCont(int conn, gdb_command_t *cmd) {
 	gdb_vcont_t *vcont;
 	int stopped_thread = -1;
 	const char *stop_reason = NULL;
+	std::map<debug_target_if *, bool> matched;
 
 	/* This handler attempts to implement the all-stop mode.
 	 * See: https://sourceware.org/gdb/onlinedocs/gdb/All_002dStop-Mode.html */
@@ -217,12 +218,21 @@ void GDBServer::vCont(int conn, gdb_command_t *cmd) {
 		bool single = false;
 		if (vcont->action == 's')
 			single = true;
-		else if (vcont->action == 'S')
+		else if (vcont->action != 'c')
 			throw std::invalid_argument("Unimplemented vCont action"); /* TODO */
 
 		std::vector<debug_target_if *> selected_harts;
 		try {
-			selected_harts = run_threads(vcont->thread.tid, single);
+			auto run = get_threads(vcont->thread.tid);
+			for (auto i = run.begin(); i != run.end();) {
+				debug_target_if *hart = *i;
+				if (matched.count(hart))
+					i = run.erase(i); /* already matched */
+				else
+					i++;
+			}
+
+			selected_harts = run_threads(run, single);
 		} catch (const std::out_of_range&) {
 			send_packet(conn, "E01");
 			return;
@@ -246,6 +256,16 @@ void GDBServer::vCont(int conn, gdb_command_t *cmd) {
 				continue;
 			}
 		}
+
+		/* The vCont specification mandates that only the leftmost action with
+		 * a matching thread-id is applied. Unfortunately, the specification
+		 * is a bit unclear in regards to handling two actions with no thread
+		 * id (i.e. GDB_THREAD_ALL). */
+		if (vcont->thread.tid > 0) {
+			auto threads = get_threads(vcont->thread.tid);
+			assert(threads.size() == 1);
+			matched[threads.front()] = true;
+		}
 	}
 
 	assert(stop_reason && stopped_thread >= 1);
diff --git a/vp/src/core/common/gdb-mc/libgdb/parser2.c b/vp/src/core/common/gdb-mc/libgdb/parser2.c
index fe9568c6b..dd9abf83a 100644
--- a/vp/src/core/common/gdb-mc/libgdb/parser2.c
+++ b/vp/src/core/common/gdb-mc/libgdb/parser2.c
@@ -223,7 +223,7 @@ gdbf_vcont(int n, mpc_val_t **xs)
 		vcont->next = (gdb_vcont_t *)xs[i];
 	vcont->next = NULL;
 
-	return vcont;
+	return (gdb_vcont_t *)xs[0];
 }
 
 gdbf_fold(vcont, GDB_ARG_VCONT, GDBF_ARG_VCONT)