diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index b3e61b9f84..953dbbd7ae 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -87,6 +87,10 @@ enum SDCardStates {
     sd_disconnect_state,
 };
 
+typedef struct SDProto {
+    const char *name;
+} SDProto;
+
 struct SDState {
     DeviceState parent_obj;
 
@@ -137,7 +141,6 @@ struct SDState {
     qemu_irq readonly_cb;
     qemu_irq inserted_cb;
     QEMUTimer *ocr_power_timer;
-    const char *proto_name;
     bool enable;
     uint8_t dat_lines;
     bool cmd_line;
@@ -145,6 +148,13 @@ struct SDState {
 
 static void sd_realize(DeviceState *dev, Error **errp);
 
+static const struct SDProto *sd_proto(SDState *sd)
+{
+    SDCardClass *sc = SD_CARD_GET_CLASS(sd);
+
+    return sc->proto;
+}
+
 static const char *sd_version_str(enum SDPhySpecificationVersion version)
 {
     static const char *sdphy_version[] = {
@@ -981,8 +991,8 @@ static bool address_in_range(SDState *sd, const char *desc,
 
 static sd_rsp_type_t sd_invalid_state_for_cmd(SDState *sd, SDRequest req)
 {
-    qemu_log_mask(LOG_GUEST_ERROR, "SD: CMD%i in a wrong state: %s (spec %s)\n",
-                  req.cmd, sd_state_name(sd->state),
+    qemu_log_mask(LOG_GUEST_ERROR, "%s: CMD%i in a wrong state: %s (spec %s)\n",
+                  sd_proto(sd)->name, req.cmd, sd_state_name(sd->state),
                   sd_version_str(sd->spec_version));
 
     return sd_illegal;
@@ -997,7 +1007,7 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
      * However there is no ACMD55, so we want to trace this particular case.
      */
     if (req.cmd != 55 || sd->expecting_acmd) {
-        trace_sdcard_normal_command(sd->proto_name,
+        trace_sdcard_normal_command(sd_proto(sd)->name,
                                     sd_cmd_name(req.cmd), req.cmd,
                                     req.arg, sd_state_name(sd->state));
     }
@@ -1562,7 +1572,7 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
 static sd_rsp_type_t sd_app_command(SDState *sd,
                                     SDRequest req)
 {
-    trace_sdcard_app_command(sd->proto_name, sd_acmd_name(req.cmd),
+    trace_sdcard_app_command(sd_proto(sd)->name, sd_acmd_name(req.cmd),
                              req.cmd, req.arg, sd_state_name(sd->state));
     sd->card_status |= APP_CMD;
     switch (req.cmd) {
@@ -1856,7 +1866,7 @@ void sd_write_byte(SDState *sd, uint8_t value)
     if (sd->card_status & (ADDRESS_ERROR | WP_VIOLATION))
         return;
 
-    trace_sdcard_write_data(sd->proto_name,
+    trace_sdcard_write_data(sd_proto(sd)->name,
                             sd_acmd_name(sd->current_cmd),
                             sd->current_cmd, value);
     switch (sd->current_cmd) {
@@ -2012,7 +2022,7 @@ uint8_t sd_read_byte(SDState *sd)
 
     io_len = (sd->ocr & (1 << 30)) ? 512 : sd->blk_len;
 
-    trace_sdcard_read_data(sd->proto_name,
+    trace_sdcard_read_data(sd_proto(sd)->name,
                            sd_acmd_name(sd->current_cmd),
                            sd->current_cmd, io_len);
     switch (sd->current_cmd) {
@@ -2131,6 +2141,14 @@ void sd_enable(SDState *sd, bool enable)
     sd->enable = enable;
 }
 
+static const SDProto sd_proto_spi = {
+    .name = "SPI",
+};
+
+static const SDProto sd_proto_sd = {
+    .name = "SD",
+};
+
 static void sd_instance_init(Object *obj)
 {
     SDState *sd = SD_CARD(obj);
@@ -2149,9 +2167,10 @@ static void sd_instance_finalize(Object *obj)
 static void sd_realize(DeviceState *dev, Error **errp)
 {
     SDState *sd = SD_CARD(dev);
+    SDCardClass *sc = SD_CARD_GET_CLASS(sd);
     int ret;
 
-    sd->proto_name = sd->spi ? "SPI" : "SD";
+    sc->proto = sd->spi ? &sd_proto_spi : &sd_proto_sd;
 
     switch (sd->spec_version) {
     case SD_PHY_SPECv1_10_VERS
diff --git a/include/hw/sd/sd.h b/include/hw/sd/sd.h
index 47360ba4ee..0d94e1f346 100644
--- a/include/hw/sd/sd.h
+++ b/include/hw/sd/sd.h
@@ -124,6 +124,8 @@ struct SDCardClass {
     void (*enable)(SDState *sd, bool enable);
     bool (*get_inserted)(SDState *sd);
     bool (*get_readonly)(SDState *sd);
+
+    const struct SDProto *proto;
 };
 
 #define TYPE_SD_BUS "sd-bus"
