diff --git a/tests/psa-client-server/psasim/include/psa/client.h b/tests/psa-client-server/psasim/include/psa/client.h
new file mode 100644
index 0000000..d1af993
--- /dev/null
+++ b/tests/psa-client-server/psasim/include/psa/client.h
@@ -0,0 +1,73 @@
+/* PSA Firmware Framework client header for psasim. */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#ifndef __PSA_CLIENT_H__
+#define __PSA_CLIENT_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include "psa/error.h"
+/*********************** PSA Client Macros and Types *************************/
+
+#define PSA_FRAMEWORK_VERSION  (0x0100)
+
+#define PSA_VERSION_NONE       (0)
+
+/* PSA response types */
+#define PSA_CONNECTION_REFUSED PSA_ERROR_CONNECTION_REFUSED
+#define PSA_CONNECTION_BUSY    PSA_ERROR_CONNECTION_BUSY
+#define PSA_DROP_CONNECTION    PSA_ERROR_PROGRAMMER_ERROR
+
+/* PSA message handles */
+#define PSA_NULL_HANDLE        ((psa_handle_t) 0)
+
+#define PSA_HANDLE_IS_VALID(handle) ((psa_handle_t) (handle) > 0)
+#define PSA_HANDLE_TO_ERROR(handle) ((psa_status_t) (handle))
+
+/**
+ * A read-only input memory region provided to an RoT Service.
+ */
+typedef struct psa_invec {
+    const void *base;
+    size_t len;
+} psa_invec;
+
+/**
+ * A writable output memory region provided to an RoT Service.
+ */
+typedef struct psa_outvec {
+    void *base;
+    size_t len;
+} psa_outvec;
+
+/*************************** PSA Client API **********************************/
+
+uint32_t psa_framework_version(void);
+
+uint32_t psa_version(uint32_t sid);
+
+psa_handle_t psa_connect(uint32_t sid, uint32_t version);
+
+psa_status_t psa_call(psa_handle_t handle,
+                      int32_t type,
+                      const psa_invec *in_vec,
+                      size_t in_len,
+                      psa_outvec *out_vec,
+                      size_t out_len);
+
+void psa_close(psa_handle_t handle);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __PSA_CLIENT_H__ */
diff --git a/tests/psa-client-server/psasim/include/psa/common.h b/tests/psa-client-server/psasim/include/psa/common.h
new file mode 100644
index 0000000..d0205d2
--- /dev/null
+++ b/tests/psa-client-server/psasim/include/psa/common.h
@@ -0,0 +1,53 @@
+/* Common definitions used for clients and services */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#ifndef _COMMON_H_
+#define _COMMON_H_
+
+#include <stdint.h>
+#include <stddef.h>
+
+/* Increasing this might break on some platforms */
+#define MAX_FRAGMENT_SIZE 200
+
+#define CONNECT_REQUEST 1
+#define CALL_REQUEST 2
+#define CLOSE_REQUEST 3
+#define VERSION_REQUEST 4
+#define READ_REQUEST    5
+#define READ_RESPONSE   6
+#define WRITE_REQUEST   7
+#define WRITE_RESPONSE  8
+#define SKIP_REQUEST    9
+#define PSA_REPLY       10
+
+#define NON_SECURE (1 << 30)
+
+typedef int32_t psa_status_t;
+typedef int32_t psa_handle_t;
+
+#define PSA_MAX_IOVEC (4u)
+
+#define PSA_IPC_CALL (0)
+
+struct message_text {
+    int qid;
+    int32_t psa_type;
+    char buf[MAX_FRAGMENT_SIZE];
+};
+
+struct message {
+    long message_type;
+    struct message_text message_text;
+};
+
+typedef struct vector_sizes {
+    size_t invec_sizes[PSA_MAX_IOVEC];
+    size_t outvec_sizes[PSA_MAX_IOVEC];
+} vector_sizes_t;
+
+#endif /* _COMMON_H_ */
diff --git a/tests/psa-client-server/psasim/include/psa/error.h b/tests/psa-client-server/psasim/include/psa/error.h
new file mode 100644
index 0000000..44fc0b1
--- /dev/null
+++ b/tests/psa-client-server/psasim/include/psa/error.h
@@ -0,0 +1,38 @@
+/* PSA status codes used by psasim. */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#ifndef PSA_ERROR_H
+#define PSA_ERROR_H
+
+#include <stdint.h>
+
+#include "psa/common.h"
+
+#define PSA_SUCCESS                     ((psa_status_t) 0)
+
+#define PSA_ERROR_PROGRAMMER_ERROR      ((psa_status_t) -129)
+#define PSA_ERROR_CONNECTION_REFUSED    ((psa_status_t) -130)
+#define PSA_ERROR_CONNECTION_BUSY       ((psa_status_t) -131)
+#define PSA_ERROR_GENERIC_ERROR         ((psa_status_t) -132)
+#define PSA_ERROR_NOT_PERMITTED         ((psa_status_t) -133)
+#define PSA_ERROR_NOT_SUPPORTED         ((psa_status_t) -134)
+#define PSA_ERROR_INVALID_ARGUMENT      ((psa_status_t) -135)
+#define PSA_ERROR_INVALID_HANDLE        ((psa_status_t) -136)
+#define PSA_ERROR_BAD_STATE             ((psa_status_t) -137)
+#define PSA_ERROR_BUFFER_TOO_SMALL      ((psa_status_t) -138)
+#define PSA_ERROR_ALREADY_EXISTS        ((psa_status_t) -139)
+#define PSA_ERROR_DOES_NOT_EXIST        ((psa_status_t) -140)
+#define PSA_ERROR_INSUFFICIENT_MEMORY   ((psa_status_t) -141)
+#define PSA_ERROR_INSUFFICIENT_STORAGE  ((psa_status_t) -142)
+#define PSA_ERROR_INSUFFICIENT_DATA     ((psa_status_t) -143)
+#define PSA_ERROR_SERVICE_FAILURE       ((psa_status_t) -144)
+#define PSA_ERROR_COMMUNICATION_FAILURE ((psa_status_t) -145)
+#define PSA_ERROR_STORAGE_FAILURE       ((psa_status_t) -146)
+#define PSA_ERROR_HARDWARE_FAILURE      ((psa_status_t) -147)
+#define PSA_ERROR_INVALID_SIGNATURE     ((psa_status_t) -149)
+
+#endif
diff --git a/tests/psa-client-server/psasim/include/psa/lifecycle.h b/tests/psa-client-server/psasim/include/psa/lifecycle.h
new file mode 100644
index 0000000..1148397
--- /dev/null
+++ b/tests/psa-client-server/psasim/include/psa/lifecycle.h
@@ -0,0 +1,17 @@
+/* PSA lifecycle states used by psasim. */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#define PSA_LIFECYCLE_PSA_STATE_MASK (0xff00u)
+#define PSA_LIFECYCLE_IMP_STATE_MASK (0x00ffu)
+#define PSA_LIFECYCLE_UNKNOWN (0x0000u)
+#define PSA_LIFECYCLE_ASSEMBLY_AND_TEST (0x1000u)
+#define PSA_LIFECYCLE_PSA_ROT_PROVISIONING (0x2000u)
+#define PSA_LIFECYCLE_SECURED (0x3000u)
+#define PSA_LIFECYCLE_NON_PSA_ROT_DEBUG (0x4000u)
+#define PSA_LIFECYCLE_RECOVERABLE_PSA_ROT_DEBUG (0x5000u)
+#define PSA_LIFECYCLE_DECOMMISSIONED (0x6000u)
+#define psa_rot_lifecycle_state(void) PSA_LIFECYCLE_UNKNOWN
diff --git a/tests/psa-client-server/psasim/include/psa/service.h b/tests/psa-client-server/psasim/include/psa/service.h
new file mode 100644
index 0000000..c8c0024
--- /dev/null
+++ b/tests/psa-client-server/psasim/include/psa/service.h
@@ -0,0 +1,251 @@
+/* PSA Firmware Framework service header for psasim. */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#ifndef __PSA_SERVICE_H__
+#define __PSA_SERVICE_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+#include <stdlib.h>
+#include <stdint.h>
+#include <stddef.h>
+
+#include "psa/common.h"
+
+/********************** PSA Secure Partition Macros and Types ****************/
+
+/* PSA wait timeouts */
+#define PSA_POLL                (0x00000000u)
+#define PSA_BLOCK               (0x80000000u)
+
+/* A mask value that includes all Secure Partition signals */
+#define PSA_WAIT_ANY            (~0u)
+
+/* Doorbell signal */
+#define PSA_DOORBELL            (0x00000008u)
+
+/* PSA message types */
+#define PSA_IPC_CONNECT         (-1)
+#define PSA_IPC_DISCONNECT      (-2)
+
+/* Return code from psa_get() */
+#define PSA_ERR_NOMSG           (INT32_MIN + 3)
+
+/* Store a set of one or more Secure Partition signals */
+typedef uint32_t psa_signal_t;
+
+/**
+ * Describe a message received by an RoT Service after calling \ref psa_get().
+ */
+typedef struct psa_msg_t {
+    uint32_t type;              /* One of the following values:
+                                 * \ref PSA_IPC_CONNECT
+                                 * \ref PSA_IPC_CALL
+                                 * \ref PSA_IPC_DISCONNECT
+                                 */
+    psa_handle_t handle;        /* A reference generated by the SPM to the
+                                 * message returned by psa_get().
+                                 */
+    int32_t client_id;          /* Partition ID of the sender of the message */
+    void *rhandle;              /* Be useful for binding a connection to some
+                                 * application-specific data or function
+                                 * pointer within the RoT Service
+                                 * implementation.
+                                 */
+    size_t in_size[PSA_MAX_IOVEC]; /* Provide the size of each client input
+                                    * vector in bytes.
+                                    */
+    size_t out_size[PSA_MAX_IOVEC];/* Provide the size of each client output
+                                    * vector in bytes.
+                                    */
+} psa_msg_t;
+
+/************************* PSA Secure Partition API **************************/
+
+/**
+ * \brief Return the Secure Partition interrupt signals that have been asserted
+ *        from a subset of signals provided by the caller.
+ *
+ * \param[in] signal_mask       A set of signals to query. Signals that are not
+ *                              in this set will be ignored.
+ * \param[in] timeout           Specify either blocking \ref PSA_BLOCK or
+ *                              polling \ref PSA_POLL operation.
+ *
+ * \retval >0                   At least one signal is asserted.
+ * \retval 0                    No signals are asserted. This is only seen when
+ *                              a polling timeout is used.
+ */
+psa_signal_t psa_wait(psa_signal_t signal_mask, uint32_t timeout);
+
+/**
+ * \brief Retrieve the message which corresponds to a given RoT Service signal
+ *        and remove the message from the RoT Service queue.
+ *
+ * \param[in] signal            The signal value for an asserted RoT Service.
+ * \param[out] msg              Pointer to \ref psa_msg_t object for receiving
+ *                              the message.
+ *
+ * \retval PSA_SUCCESS          Success, *msg will contain the delivered
+ *                              message.
+ * \retval PSA_ERR_NOMSG        Message could not be delivered.
+ * \retval "Does not return"    The call is invalid because one or more of the
+ *                              following are true:
+ * \arg                           signal has more than a single bit set.
+ * \arg                           signal does not correspond to an RoT Service.
+ * \arg                           The RoT Service signal is not currently
+ *                                asserted.
+ * \arg                           The msg pointer provided is not a valid memory
+ *                                reference.
+ */
+psa_status_t psa_get(psa_signal_t signal, psa_msg_t *msg);
+
+/**
+ * \brief Associate some RoT Service private data with a client connection.
+ *
+ * \param[in] msg_handle        Handle for the client's message.
+ * \param[in] rhandle           Reverse handle allocated by the RoT Service.
+ *
+ * \retval void                 Success, rhandle will be provided with all
+ *                              subsequent messages delivered on this
+ *                              connection.
+ * \retval "Does not return"    msg_handle is invalid.
+ */
+void psa_set_rhandle(psa_handle_t msg_handle, void *rhandle);
+
+/**
+ * \brief Read a message parameter or part of a message parameter from a client
+ *        input vector.
+ *
+ * \param[in] msg_handle        Handle for the client's message.
+ * \param[in] invec_idx         Index of the input vector to read from. Must be
+ *                              less than \ref PSA_MAX_IOVEC.
+ * \param[out] buffer           Buffer in the Secure Partition to copy the
+ *                              requested data to.
+ * \param[in] num_bytes         Maximum number of bytes to be read from the
+ *                              client input vector.
+ *
+ * \retval >0                   Number of bytes copied.
+ * \retval 0                    There was no remaining data in this input
+ *                              vector.
+ * \retval "Does not return"    The call is invalid, one or more of the
+ *                              following are true:
+ * \arg                           msg_handle is invalid.
+ * \arg                           msg_handle does not refer to a
+ *                                \ref PSA_IPC_CALL message.
+ * \arg                           invec_idx is equal to or greater than
+ *                                \ref PSA_MAX_IOVEC.
+ * \arg                           the memory reference for buffer is invalid or
+ *                                not writable.
+ */
+size_t psa_read(psa_handle_t msg_handle, uint32_t invec_idx,
+                void *buffer, size_t num_bytes);
+
+/**
+ * \brief Skip over part of a client input vector.
+ *
+ * \param[in] msg_handle        Handle for the client's message.
+ * \param[in] invec_idx         Index of input vector to skip from. Must be
+ *                              less than \ref PSA_MAX_IOVEC.
+ * \param[in] num_bytes         Maximum number of bytes to skip in the client
+ *                              input vector.
+ *
+ * \retval >0                   Number of bytes skipped.
+ * \retval 0                    There was no remaining data in this input
+ *                              vector.
+ * \retval "Does not return"    The call is invalid, one or more of the
+ *                              following are true:
+ * \arg                           msg_handle is invalid.
+ * \arg                           msg_handle does not refer to a
+ *                                \ref PSA_IPC_CALL message.
+ * \arg                           invec_idx is equal to or greater than
+ *                                \ref PSA_MAX_IOVEC.
+ */
+size_t psa_skip(psa_handle_t msg_handle, uint32_t invec_idx, size_t num_bytes);
+
+/**
+ * \brief Write a message response to a client output vector.
+ *
+ * \param[in] msg_handle        Handle for the client's message.
+ * \param[out] outvec_idx       Index of output vector in message to write to.
+ *                              Must be less than \ref PSA_MAX_IOVEC.
+ * \param[in] buffer            Buffer with the data to write.
+ * \param[in] num_bytes         Number of bytes to write to the client output
+ *                              vector.
+ *
+ * \retval void                 Success
+ * \retval "Does not return"    The call is invalid, one or more of the
+ *                              following are true:
+ * \arg                           msg_handle is invalid.
+ * \arg                           msg_handle does not refer to a
+ *                                \ref PSA_IPC_CALL message.
+ * \arg                           outvec_idx is equal to or greater than
+ *                                \ref PSA_MAX_IOVEC.
+ * \arg                           The memory reference for buffer is invalid.
+ * \arg                           The call attempts to write data past the end
+ *                                of the client output vector.
+ */
+void psa_write(psa_handle_t msg_handle, uint32_t outvec_idx,
+               const void *buffer, size_t num_bytes);
+
+/**
+ * \brief Complete handling of a specific message and unblock the client.
+ *
+ * \param[in] msg_handle        Handle for the client's message.
+ * \param[in] status            Message result value to be reported to the
+ *                              client.
+ *
+ * \retval void                 Success.
+ * \retval "Does not return"    The call is invalid, one or more of the
+ *                              following are true:
+ * \arg                         msg_handle is invalid.
+ * \arg                         An invalid status code is specified for the
+ *                              type of message.
+ */
+void psa_reply(psa_handle_t msg_handle, psa_status_t status);
+
+/**
+ * \brief Send a PSA_DOORBELL signal to a specific Secure Partition.
+ *
+ * \param[in] partition_id      Secure Partition ID of the target partition.
+ *
+ * \retval void                 Success.
+ * \retval "Does not return"    partition_id does not correspond to a Secure
+ *                              Partition.
+ */
+void psa_notify(int32_t partition_id);
+
+/**
+ * \brief Clear the PSA_DOORBELL signal.
+ *
+ * \retval void                 Success.
+ * \retval "Does not return"    The Secure Partition's doorbell signal is not
+ *                              currently asserted.
+ */
+void psa_clear(void);
+
+/**
+ * \brief Inform the SPM that an interrupt has been handled (end of interrupt).
+ *
+ * \param[in] irq_signal        The interrupt signal that has been processed.
+ *
+ * \retval void                 Success.
+ * \retval "Does not return"    The call is invalid, one or more of the
+ *                              following are true:
+ * \arg                           irq_signal is not an interrupt signal.
+ * \arg                           irq_signal indicates more than one signal.
+ * \arg                           irq_signal is not currently asserted.
+ */
+void psa_eoi(psa_signal_t irq_signal);
+
+#define psa_panic(X) abort();
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __PSA_SERVICE_H__ */
diff --git a/tests/psa-client-server/psasim/include/psa/util.h b/tests/psa-client-server/psasim/include/psa/util.h
new file mode 100644
index 0000000..c3669a1
--- /dev/null
+++ b/tests/psa-client-server/psasim/include/psa/util.h
@@ -0,0 +1,33 @@
+/* Common definitions used for clients and services */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#include "psa/service.h"
+
+#define PRINT(fmt, ...) \
+    fprintf(stdout, fmt "\n", ##__VA_ARGS__)
+
+#if defined(DEBUG)
+#define INFO(fmt, ...) \
+    fprintf(stdout, "Info (%s - %d): " fmt "\n", __FILE__, __LINE__, ##__VA_ARGS__)
+
+#define ERROR(fmt, ...) \
+    fprintf(stdout, "Error (%s - %d): " fmt "\n", __FILE__, __LINE__, ##__VA_ARGS__)
+
+#define FATAL(fmt, ...) \
+    { \
+        fprintf(stdout, "Fatal (%s - %d): " fmt "\n", __FILE__, __LINE__, ##__VA_ARGS__); \
+        abort(); \
+    }
+#else /* DEBUG */
+#define INFO(...)
+#define ERROR(...)
+#define FATAL(...)
+#endif /* DEBUG*/
+
+#define PROJECT_ID              'M'
+#define PATHNAMESIZE            256
+#define TMP_FILE_BASE_PATH      "./"
diff --git a/tests/psa-client-server/psasim/include/psasim/init.h b/tests/psa-client-server/psasim/include/psasim/init.h
new file mode 100644
index 0000000..9496fc2
--- /dev/null
+++ b/tests/psa-client-server/psasim/include/psasim/init.h
@@ -0,0 +1,15 @@
+/* Declarations of internal functions. */
+
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#include <stdint.h>
+#include <psa/service.h>
+void raise_signal(psa_signal_t signal);
+void __init_psasim(const char **array,
+                   int size,
+                   const int allow_ns_clients_array[32],
+                   const uint32_t versions[32],
+                   const int strict_policy_array[32]);