Merge pull request #119 from devimc/topic/qemu/AddPmem

qemu: add pmem flag to memory-backend-file

qemu/qmp.go

@@ -1428,8 +1428,9 @@ func (q *QMP) ExecHotplugMemory(ctx context.Context, qomtype, id, mempath string
 // a NVDIMM driver with the device_add command.
 // id is the id of the device to add.  It must be a valid QMP identifier.
 // mempath is the path of the device to add, e.g., /dev/rdb0.  size is
-// the data size of the device.
-func (q *QMP) ExecuteNVDIMMDeviceAdd(ctx context.Context, id, mempath string, size int64) error {
+// the data size of the device. pmem is to guarantee the persistence of QEMU writes
+// to the vNVDIMM backend.
+func (q *QMP) ExecuteNVDIMMDeviceAdd(ctx context.Context, id, mempath string, size int64, pmem *bool) error {
 	args := map[string]interface{}{
 		"qom-type": "memory-backend-file",
 		"id":       "nvdimmbackmem" + id,
@@ -1439,6 +1440,14 @@ func (q *QMP) ExecuteNVDIMMDeviceAdd(ctx context.Context, id, mempath string, si
 			"share":    true,
 		},
 	}
+
+	if q.version.Major > 4 || (q.version.Major == 4 && q.version.Minor >= 1) {
+		if pmem != nil {
+			props := args["props"].(map[string]interface{})
+			props["pmem"] = *pmem
+		}
+	}
+
 	err := q.executeCommand(ctx, "object-add", args, nil)
 	if err != nil {
 		return err

qemu/qmp_test.go

@@ -1617,7 +1617,12 @@ func TestExecuteNVDIMMDeviceAdd(t *testing.T) {
 	cfg := QMPConfig{Logger: qmpTestLogger{}}
 	q := startQMPLoop(buf, cfg, connectedCh, disconnectedCh)
 	checkVersion(t, connectedCh)
-	err := q.ExecuteNVDIMMDeviceAdd(context.Background(), "nvdimm0", "/dev/rbd0", 1024)
+	q.version = &QMPVersion{
+		Major: 4,
+		Minor: 1,
+	}
+	pmem := true
+	err := q.ExecuteNVDIMMDeviceAdd(context.Background(), "nvdimm0", "/dev/rbd0", 1024, &pmem)
 	if err != nil {
 		t.Fatalf("Unexpected error: %v", err)
 	}