diff --git a/src/pcrextend/pcrextend.c b/src/pcrextend/pcrextend.c
index d887da924f..c80bf376fd 100644
--- a/src/pcrextend/pcrextend.c
+++ b/src/pcrextend/pcrextend.c
@@ -369,6 +369,7 @@ typedef struct MethodExtendParameters {
         const char *nvpcr;
         const char *text;
         struct iovec data;
+        Tpm2UserspaceEventType event_type;
 } MethodExtendParameters;
 
 static void method_extend_parameters_done(MethodExtendParameters *p) {
@@ -377,17 +378,21 @@ static void method_extend_parameters_done(MethodExtendParameters *p) {
         iovec_done(&p->data);
 }
 
+static JSON_DISPATCH_ENUM_DEFINE(json_dispatch_tpm2_userspace_event_type, Tpm2UserspaceEventType, tpm2_userspace_event_type_from_string);
+
 static int vl_method_extend(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "pcr",   _SD_JSON_VARIANT_TYPE_INVALID, sd_json_dispatch_uint,         offsetof(MethodExtendParameters, pcr),   0 },
-                { "nvpcr", SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, offsetof(MethodExtendParameters, nvpcr), 0 },
-                { "text",  SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, offsetof(MethodExtendParameters, text),  0 },
-                { "data",  SD_JSON_VARIANT_STRING,        json_dispatch_unbase64_iovec,  offsetof(MethodExtendParameters, data),  0 },
+                { "pcr",       _SD_JSON_VARIANT_TYPE_INVALID, sd_json_dispatch_uint,                   offsetof(MethodExtendParameters, pcr),   0 },
+                { "nvpcr",     SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string,           offsetof(MethodExtendParameters, nvpcr), 0 },
+                { "text",      SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string,           offsetof(MethodExtendParameters, text),  0 },
+                { "data",      SD_JSON_VARIANT_STRING,        json_dispatch_unbase64_iovec,            offsetof(MethodExtendParameters, data),   0 },
+                { "eventType", SD_JSON_VARIANT_STRING,        json_dispatch_tpm2_userspace_event_type, offsetof(MethodExtendParameters, event_type), 0 },
                 {}
         };
         _cleanup_(method_extend_parameters_done) MethodExtendParameters p = {
                 .pcr = UINT_MAX,
+                .event_type = _TPM2_USERSPACE_EVENT_TYPE_INVALID,
         };
         int r;
 
@@ -424,11 +429,11 @@ static int vl_method_extend(sd_varlink *link, sd_json_variant *parameters, sd_va
                 return sd_varlink_error_invalid_parameter_name(link, "text");
 
         if (p.nvpcr) {
-                r = extend_nvpcr_now(p.nvpcr, extend_iovec->iov_base, extend_iovec->iov_len, _TPM2_USERSPACE_EVENT_TYPE_INVALID);
+                r = extend_nvpcr_now(p.nvpcr, extend_iovec->iov_base, extend_iovec->iov_len, p.event_type);
                 if (r == -ENOENT)
                         return sd_varlink_error(link, "io.systemd.PCRExtend.NoSuchNvPCR", NULL);
         } else
-                r = extend_pcr_now(p.pcr, extend_iovec->iov_base, extend_iovec->iov_len, _TPM2_USERSPACE_EVENT_TYPE_INVALID);
+                r = extend_pcr_now(p.pcr, extend_iovec->iov_base, extend_iovec->iov_len, p.event_type);
         if (r < 0)
                 return r;
 
diff --git a/src/shared/varlink-io.systemd.PCRExtend.c b/src/shared/varlink-io.systemd.PCRExtend.c
index 87783f1ee9..9179668d7d 100644
--- a/src/shared/varlink-io.systemd.PCRExtend.c
+++ b/src/shared/varlink-io.systemd.PCRExtend.c
@@ -2,6 +2,17 @@
 
 #include "varlink-io.systemd.PCRExtend.h"
 
+static SD_VARLINK_DEFINE_ENUM_TYPE(
+                EventType,
+                SD_VARLINK_DEFINE_ENUM_VALUE(phase),
+                SD_VARLINK_DEFINE_ENUM_VALUE(filesystem),
+                SD_VARLINK_DEFINE_ENUM_VALUE(volume_key),
+                SD_VARLINK_DEFINE_ENUM_VALUE(machine_id),
+                SD_VARLINK_DEFINE_ENUM_VALUE(product_id),
+                SD_VARLINK_DEFINE_ENUM_VALUE(keyslot),
+                SD_VARLINK_DEFINE_ENUM_VALUE(nvpcr_init),
+                SD_VARLINK_DEFINE_ENUM_VALUE(nvpcr_separator));
+
 static SD_VARLINK_DEFINE_METHOD(
                 Extend,
                 SD_VARLINK_FIELD_COMMENT("PCR number to extend, in range of 0…23. Either this or 'nvpcr' must be specified, not both, not neither."),
@@ -11,7 +22,9 @@ static SD_VARLINK_DEFINE_METHOD(
                 SD_VARLINK_FIELD_COMMENT("Text string to measure. (Specify either this, or the 'data' field below, not both)"),
                 SD_VARLINK_DEFINE_INPUT(text, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
                 SD_VARLINK_FIELD_COMMENT("Binary data to measure, encoded in Base64. (Specify either this, or the 'text' field above, not both)"),
-                SD_VARLINK_DEFINE_INPUT(data, SD_VARLINK_STRING, SD_VARLINK_NULLABLE));
+                SD_VARLINK_DEFINE_INPUT(data, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("Event type to include in the (userspace) event log). This is optional, and mostly for debugging."),
+                SD_VARLINK_DEFINE_INPUT_BY_TYPE(eventType, EventType, SD_VARLINK_NULLABLE));
 
 static SD_VARLINK_DEFINE_ERROR(NoSuchNvPCR);
 
@@ -21,4 +34,6 @@ SD_VARLINK_DEFINE_INTERFACE(
                 SD_VARLINK_INTERFACE_COMMENT("TPM PCR Extension APIs"),
                 SD_VARLINK_SYMBOL_COMMENT("Measure some text or binary data into a PCR"),
                 &vl_method_Extend,
+                SD_VARLINK_SYMBOL_COMMENT("Event type to store in event log"),
+                &vl_type_EventType,
                 &vl_error_NoSuchNvPCR);