diff --git a/plugins/teststeps/qemu/events.go b/plugins/teststeps/qemu/events.go
index 829ac505..e1a19790 100644
--- a/plugins/teststeps/qemu/events.go
+++ b/plugins/teststeps/qemu/events.go
@@ -55,8 +55,8 @@ func (ts TestStep) writeTestStep(builders ...*strings.Builder) {
 		builder.WriteString("Input Parameters:\n")
 		builder.WriteString(fmt.Sprintf("  Executable: %s\n", ts.Executable))
 		builder.WriteString(fmt.Sprintf("  Firmware: %s\n", ts.Firmware))
-		builder.WriteString(fmt.Sprintf("  Nproc: %s\n", ts.Nproc))
-		builder.WriteString(fmt.Sprintf("  Mem: %s\n", ts.Mem))
+		builder.WriteString(fmt.Sprintf("  Nproc: %d\n", ts.Nproc))
+		builder.WriteString(fmt.Sprintf("  Mem: %d\n", ts.Mem))
 		builder.WriteString(fmt.Sprintf("  Image: %s\n", ts.Image))
 		builder.WriteString(fmt.Sprintf("  Logfile: %s\n", ts.Logfile))
 		builder.WriteString("  Steps:\n")
diff --git a/plugins/teststeps/qemu/main.go b/plugins/teststeps/qemu/main.go
index f0863a25..a14883b3 100644
--- a/plugins/teststeps/qemu/main.go
+++ b/plugins/teststeps/qemu/main.go
@@ -32,8 +32,8 @@ const (
 type parameters struct {
 	Executable string `json:"executable"`
 	Firmware   string `json:"firmware"`
-	Nproc      string `json:"nproc,omitempty"`
-	Mem        string `json:"mem,omitempty"`
+	Nproc      int    `json:"nproc,omitempty"`
+	Mem        int    `json:"mem,omitempty"`
 	Image      string `json:"image,omitempty"`
 	Logfile    string `json:"logfile,omitempty"`
 	Steps      []struct {
diff --git a/plugins/teststeps/qemu/runner.go b/plugins/teststeps/qemu/runner.go
index b008df44..1e413413 100644
--- a/plugins/teststeps/qemu/runner.go
+++ b/plugins/teststeps/qemu/runner.go
@@ -48,7 +48,7 @@ func (r *TargetRunner) Run(ctx xcontext.Context, target *target.Target) error {
 func (ts *TestStep) runQemu(ctx xcontext.Context, outputBuf *strings.Builder) error {
 	// no graphical output and no network access
 	command := []string{ts.Executable, "-nographic", "-nic", "none", "-bios", ts.Firmware}
-	qemuOpts := []string{"-m", ts.Mem, "-smp", ts.Nproc}
+	qemuOpts := []string{"-m", fmt.Sprintf("%d", ts.Mem), "-smp", fmt.Sprintf("%d", ts.Nproc)}
 
 	command = append(command, qemuOpts...)
 	if ts.Image != "" {