},
 };
 
+#define PASS_TRY_LIMIT 3
+
 struct cxl_mockmem_data {
        void *lsa;
        u32 security_state;
+       u8 user_pass[NVDIMM_PASSPHRASE_LEN];
+       u8 master_pass[NVDIMM_PASSPHRASE_LEN];
+       int user_limit;
+       int master_limit;
+
 };
 
 static int mock_gsl(struct cxl_mbox_cmd *cmd)
        return 0;
 }
 
+static void master_plimit_check(struct cxl_mockmem_data *mdata)
+{
+       if (mdata->master_limit == PASS_TRY_LIMIT)
+               return;
+       mdata->master_limit++;
+       if (mdata->master_limit == PASS_TRY_LIMIT)
+               mdata->security_state |= CXL_PMEM_SEC_STATE_MASTER_PLIMIT;
+}
+
+static void user_plimit_check(struct cxl_mockmem_data *mdata)
+{
+       if (mdata->user_limit == PASS_TRY_LIMIT)
+               return;
+       mdata->user_limit++;
+       if (mdata->user_limit == PASS_TRY_LIMIT)
+               mdata->security_state |= CXL_PMEM_SEC_STATE_USER_PLIMIT;
+}
+
+static int mock_set_passphrase(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd)
+{
+       struct cxl_mockmem_data *mdata = dev_get_drvdata(cxlds->dev);
+       struct cxl_set_pass *set_pass;
+
+       if (cmd->size_in != sizeof(*set_pass))
+               return -EINVAL;
+
+       if (cmd->size_out != 0)
+               return -EINVAL;
+
+       if (mdata->security_state & CXL_PMEM_SEC_STATE_FROZEN) {
+               cmd->return_code = CXL_MBOX_CMD_RC_SECURITY;
+               return -ENXIO;
+       }
+
+       set_pass = cmd->payload_in;
+       switch (set_pass->type) {
+       case CXL_PMEM_SEC_PASS_MASTER:
+               if (mdata->security_state & CXL_PMEM_SEC_STATE_MASTER_PLIMIT) {
+                       cmd->return_code = CXL_MBOX_CMD_RC_SECURITY;
+                       return -ENXIO;
+               }
+               /*
+                * CXL spec rev3.0 8.2.9.8.6.2, The master pasphrase shall only be set in
+                * the security disabled state when the user passphrase is not set.
+                */
+               if (mdata->security_state & CXL_PMEM_SEC_STATE_USER_PASS_SET) {
+                       cmd->return_code = CXL_MBOX_CMD_RC_SECURITY;
+                       return -ENXIO;
+               }
+               if (memcmp(mdata->master_pass, set_pass->old_pass, NVDIMM_PASSPHRASE_LEN)) {
+                       master_plimit_check(mdata);
+                       cmd->return_code = CXL_MBOX_CMD_RC_PASSPHRASE;
+                       return -ENXIO;
+               }
+               memcpy(mdata->master_pass, set_pass->new_pass, NVDIMM_PASSPHRASE_LEN);
+               mdata->security_state |= CXL_PMEM_SEC_STATE_MASTER_PASS_SET;
+               return 0;
+
+       case CXL_PMEM_SEC_PASS_USER:
+               if (mdata->security_state & CXL_PMEM_SEC_STATE_USER_PLIMIT) {
+                       cmd->return_code = CXL_MBOX_CMD_RC_SECURITY;
+                       return -ENXIO;
+               }
+               if (memcmp(mdata->user_pass, set_pass->old_pass, NVDIMM_PASSPHRASE_LEN)) {
+                       user_plimit_check(mdata);
+                       cmd->return_code = CXL_MBOX_CMD_RC_PASSPHRASE;
+                       return -ENXIO;
+               }
+               memcpy(mdata->user_pass, set_pass->new_pass, NVDIMM_PASSPHRASE_LEN);
+               mdata->security_state |= CXL_PMEM_SEC_STATE_USER_PASS_SET;
+               return 0;
+
+       default:
+               cmd->return_code = CXL_MBOX_CMD_RC_INPUT;
+       }
+       return -EINVAL;
+}
+
 static int mock_get_lsa(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd)
 {
        struct cxl_mbox_get_lsa *get_lsa = cmd->payload_in;
        case CXL_MBOX_OP_GET_SECURITY_STATE:
                rc = mock_get_security_state(cxlds, cmd);
                break;
+       case CXL_MBOX_OP_SET_PASSPHRASE:
+               rc = mock_set_passphrase(cxlds, cmd);
+               break;
        default:
                break;
        }