diff --git a/tests/sys/cam/ctl/Makefile b/tests/sys/cam/ctl/Makefile
index 1333397af464..05f0831fc8b0 100644
--- a/tests/sys/cam/ctl/Makefile
+++ b/tests/sys/cam/ctl/Makefile
@@ -1,14 +1,20 @@
 PACKAGE=	tests
 
 TESTSDIR=	${TESTSBASE}/sys/cam/ctl
+BINDIR=${TESTSDIR}
 
 ${PACKAGE}FILES+=	ctl.subr
 
+ATF_TESTS_SH+=	persist
 ATF_TESTS_SH+=	prevent
 ATF_TESTS_SH+=	read_buffer
 ATF_TESTS_SH+=	start_stop_unit
 
+PROGS+=	prout_register_huge_cdb
+LIBADD+=	cam
+CFLAGS+=	-I${SRCTOP}/sys
+
 # Must be exclusive because it disables/enables camsim
 TEST_METADATA+=	is_exclusive="true"
 
 .include <bsd.test.mk>
diff --git a/tests/sys/cam/ctl/persist.sh b/tests/sys/cam/ctl/persist.sh
new file mode 100644
index 000000000000..2a350ee4775a
--- /dev/null
+++ b/tests/sys/cam/ctl/persist.sh
@@ -0,0 +1,349 @@
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2024 ConnectWise
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+. $(atf_get_srcdir)/ctl.subr
+
+# TODO
+# * PRIN READ RESERVATION, with one reservation
+# * PROUT with illegal type
+# * PROUT REGISTER AND IGNORE EXISTING KEY
+# * PROUT REGISTER AND IGNORE EXISTING KEY with a RESERVATION KEY that isn't registered
+# * PROUT REGISTER AND IGNORE EXISTING KEY to unregister
+# * PROUT CLEAR allows previously prevented medium removal
+# * PROUT PREEMPT
+# * PROUT PREEMPT with a RESERVATION KEY that isn't registered
+# * PROUT PREEMPT_AND_ABORT
+# * PROUT PREEMPT_AND_ABORT with a RESERVATION KEY that isn't registered
+# * PROUT REGISTER AND MOVE
+# * PROUT REGISTER AND MOVE with a RESERVATION KEY that isn't registered
+# * multiple initiators
+
+# Not Tested
+# * PROUT REPLACE LOST RESERVATION (not supported by ctl)
+# * Specify Initiator Ports bit (not supported by ctl)
+# * Activate Persist Through Power Loss bit (not supported by ctl)
+# * All Target Ports bit (not supported by ctl)
+
+RESERVATION_KEY=0xdeadbeef1a7ebabe
+
+atf_test_case prin_read_full_status_empty cleanup
+prin_read_full_status_empty_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION IN with the READ FULL STATUS service action, with no status descriptors"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prin_read_full_status_empty_body()
+{
+	create_ramdisk
+
+	atf_check -o match:"No full status descriptors" sg_persist -ns /dev/$dev
+}
+prin_read_full_status_empty_cleanup()
+{
+	cleanup
+}
+
+atf_test_case prin_read_keys_empty cleanup
+prin_read_keys_empty_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION IN with the READ KEYS service action, with no registered keys"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prin_read_keys_empty_body()
+{
+	create_ramdisk
+
+	atf_check -o match:"there are NO registered reservation keys" sg_persist -nk /dev/$dev
+}
+prin_read_keys_empty_cleanup()
+{
+	cleanup
+}
+
+atf_test_case prin_read_reservation_empty cleanup
+prin_read_reservation_empty_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION IN with the READ RESERVATION service action, with no reservations"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prin_read_reservation_empty_body()
+{
+	create_ramdisk
+
+	atf_check -o match:"there is NO reservation held" sg_persist -nr /dev/$dev
+}
+prin_read_reservation_empty_cleanup()
+{
+	cleanup
+}
+
+atf_test_case prin_report_capabilities cleanup
+prin_report_capabilities_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION IN with the REPORT CAPABILITIES service action"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prin_report_capabilities_body()
+{
+	create_ramdisk
+
+	cat > expected <<HERE
+Report capabilities response:
+  Replace Lost Reservation Capable(RLR_C): 0
+  Compatible Reservation Handling(CRH): 1
+  Specify Initiator Ports Capable(SIP_C): 0
+  All Target Ports Capable(ATP_C): 0
+  Persist Through Power Loss Capable(PTPL_C): 0
+  Type Mask Valid(TMV): 1
+  Allow Commands: 5
+  Persist Through Power Loss Active(PTPL_A): 0
+    Support indicated in Type mask:
+      Write Exclusive, all registrants: 1
+      Exclusive Access, registrants only: 1
+      Write Exclusive, registrants only: 1
+      Exclusive Access: 1
+      Write Exclusive: 1
+      Exclusive Access, all registrants: 1
+HERE
+	atf_check -o file:expected sg_persist -nc /dev/$dev
+}
+prin_report_capabilities_cleanup()
+{
+	cleanup
+}
+
+atf_test_case prout_clear cleanup
+prout_clear_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION OUT with the CLEAR service action"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prout_clear_body()
+{
+	create_ramdisk
+
+	# First register a key
+	atf_check sg_persist -n --out --param-rk=0 --param-sark=$RESERVATION_KEY -G /dev/$dev
+
+	# Then make a reservation using that key
+	atf_check sg_persist -n --out --param-rk=$RESERVATION_KEY --reserve --prout-type=8 /dev/$dev
+
+	# Now, clear all reservations and registrations
+	atf_check sg_persist -n --out --param-rk=$RESERVATION_KEY --clear /dev/$dev
+
+	# Finally, check that all reservations and keys are gone
+	atf_check -o match:"there is NO reservation held" sg_persist -nr /dev/$dev
+	atf_check -o match:"there are NO registered reservation keys" sg_persist -nk /dev/$dev
+}
+prout_clear_cleanup()
+{
+	cleanup
+}
+
+
+atf_test_case prout_register cleanup
+prout_register_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION OUT with the REGISTER service action"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prout_register_body()
+{
+	create_ramdisk
+	atf_check sg_persist -n --out --param-rk=0 --param-sark=$RESERVATION_KEY -G /dev/$dev
+	atf_check -o match:$RESERVATION_KEY sg_persist -nk /dev/$dev
+}
+prout_register_cleanup()
+{
+	cleanup
+}
+
+atf_test_case prout_register_duplicate cleanup
+prout_register_duplicate_head()
+{
+	atf_set "descr" "attempting to register a key twice should fail"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prout_register_duplicate_body()
+{
+	create_ramdisk
+	atf_check sg_persist -n --out --param-rk=0 --param-sark=$RESERVATION_KEY -G /dev/$dev
+	atf_check -s exit:24 -e match:"Reservation conflict" sg_persist -n --out --param-rk=0 --param-sark=$RESERVATION_KEY -G /dev/$dev
+	atf_check -o match:$RESERVATION_KEY sg_persist -nk /dev/$dev
+}
+prout_register_duplicate_cleanup()
+{
+	cleanup
+}
+
+atf_test_case prout_register_huge_cdb cleanup
+prout_register_huge_cdb_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION OUT with an enormous CDB size should not cause trouble"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prout_register_huge_cdb_body()
+{
+	create_ramdisk
+
+	atf_check -s exit:1 $(atf_get_srcdir)/prout_register_huge_cdb $LUN
+}
+prout_register_huge_cdb_cleanup()
+{
+	cleanup
+}
+
+atf_test_case prout_register_unregister cleanup
+prout_register_unregister_head()
+{
+	atf_set "descr" "use PERSISTENT RESERVATION OUT with the REGISTER service action to remove a prior registration"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prout_register_unregister_body()
+{
+	create_ramdisk
+	# First register a key
+	atf_check sg_persist -n --out --param-rk=0 --param-sark=$RESERVATION_KEY -G /dev/$dev
+	# Then unregister it
+	atf_check sg_persist -n --out --param-sark=0 --param-rk=$RESERVATION_KEY -G /dev/$dev
+	# Finally, check that no keys are registered
+	atf_check -o match:"there are NO registered reservation keys" sg_persist -nk /dev/$dev
+}
+prout_register_unregister_cleanup()
+{
+	cleanup
+}
+
+atf_test_case prout_release cleanup
+prout_release_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION OUT with the RESERVE service action"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prout_release_body()
+{
+	create_ramdisk
+
+	# First register a key
+	atf_check sg_persist -n --out --param-rk=0 --param-sark=$RESERVATION_KEY -G /dev/$dev
+
+	# Then make a reservation using that key
+	atf_check sg_persist -n --out --param-rk=$RESERVATION_KEY --reserve --prout-type=8 /dev/$dev
+	atf_check sg_persist -n --out --param-rk=$RESERVATION_KEY --prout-type=8 --release /dev/$dev
+
+	# Now check that the reservation is released
+	atf_check -o match:"there is NO reservation held" sg_persist -nr /dev/$dev
+	# But the registration shouldn't be.
+	atf_check -o match:$RESERVATION_KEY sg_persist -nk /dev/$dev
+}
+prout_release_cleanup()
+{
+	cleanup
+}
+
+
+atf_test_case prout_reserve cleanup
+prout_reserve_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION OUT with the RESERVE service action"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist ctladm
+}
+prout_reserve_body()
+{
+	create_ramdisk
+	# First register a key
+	atf_check sg_persist -n --out --param-rk=0 --param-sark=$RESERVATION_KEY -G /dev/$dev
+	# Then make a reservation using that key
+	atf_check sg_persist -n --out --param-rk=$RESERVATION_KEY --reserve --prout-type=8 /dev/$dev
+	# Finally, check that the reservation is correct
+	cat > expected <<HERE
+  PR generation=0x1
+    Key=0xdeadbeef1a7ebabe
+      All target ports bit clear
+      Relative port address: 0x0
+      << Reservation holder >>
+      scope: LU_SCOPE,  type: Exclusive Access, all registrants
+      Transport Id of initiator:
+        Parallel SCSI initiator SCSI address: 0x1
+        relative port number (of corresponding target): 0x0
+HERE
+	atf_check -o file:expected sg_persist -ns /dev/$dev
+}
+prout_reserve_cleanup()
+{
+	cleanup
+}
+
+atf_test_case prout_reserve_bad_scope cleanup
+prout_reserve_bad_scope_head()
+{
+	atf_set "descr" "PERSISTENT RESERVATION OUT will be rejected with an unknown scope field"
+	atf_set "require.user" "root"
+	atf_set "require.progs" sg_persist camcontrol ctladm
+}
+prout_reserve_bad_scope_body()
+{
+	create_ramdisk
+	# First register a key
+	atf_check sg_persist -n --out --param-rk=0 --param-sark=$RESERVATION_KEY -G /dev/$dev
+
+	# Then make a reservation using that key
+	atf_check -s exit:1 -e match:"ILLEGAL REQUEST asc:24,0 .Invalid field in CDB." camcontrol persist $dev -o reserve -k $RESERVATION_KEY -T read_shared -s 15 -v
+
+	# Finally, check that nothing has been reserved
+	atf_check -o match:"there is NO reservation held" sg_persist -nr /dev/$dev
+}
+prout_reserve_bad_scope_cleanup()
+{
+	cleanup
+}
+
+
+atf_init_test_cases()
+{
+	atf_add_test_case prin_read_full_status_empty
+	atf_add_test_case prin_read_keys_empty
+	atf_add_test_case prin_read_reservation_empty
+	atf_add_test_case prin_report_capabilities
+	atf_add_test_case prout_clear
+	atf_add_test_case prout_register
+	atf_add_test_case prout_register_duplicate
+	atf_add_test_case prout_register_huge_cdb
+	atf_add_test_case prout_register_unregister
+	atf_add_test_case prout_release
+	atf_add_test_case prout_reserve
+	atf_add_test_case prout_reserve_bad_scope
+}
diff --git a/tests/sys/cam/ctl/prout_register_huge_cdb.c b/tests/sys/cam/ctl/prout_register_huge_cdb.c
new file mode 100644
index 000000000000..f57a6abfadd6
--- /dev/null
+++ b/tests/sys/cam/ctl/prout_register_huge_cdb.c
@@ -0,0 +1,88 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2024 ConnectWise
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Helper that sends a PERSISTENT RESERVATION OUT command to CTL with a
+ * ridiculously huge size for the length of the CDB.  This is not possible with
+ * ctladm, for good reason.
+ */
+#include <camlib.h>
+#include <err.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include <cam/scsi/scsi_message.h>
+#include <cam/ctl/ctl_io.h>
+#include <cam/ctl/ctl.h>
+#include <cam/ctl/ctl_ioctl.h>
+#include <cam/ctl/ctl_util.h>
+
+int
+main(int argc, char **argv)
+{
+	union ctl_io *io;
+	int fd = open("/dev/cam/ctl", O_RDWR);
+	int r;
+	uint32_t targ_port;
+
+	if (argc < 2)
+		errx(2, "usage: prout_register_huge_cdb <target_port>\n");
+
+	targ_port = strtoul(argv[1], NULL, 10);
+
+	io = calloc(1, sizeof(*io));
+	io->io_hdr.nexus.initid = 7;	/* 7 is ctladm's default initiator id */
+	io->io_hdr.nexus.targ_port = targ_port;
+	io->io_hdr.nexus.targ_mapped_lun = 0;
+	io->io_hdr.nexus.targ_lun = 0;
+	io->io_hdr.io_type = CTL_IO_SCSI;
+	io->taskio.tag_type = CTL_TAG_UNTAGGED;
+	uint8_t cdb[32] = {};
+	// ctl_persistent_reserve_out// 5f 00
+	cdb[0] = 0x5f;
+	cdb[1] = 0x00;
+	struct scsi_per_res_out *cdb_ = ( struct scsi_per_res_out *)cdb;
+	// Claim an enormous size of the CDB, but don't actually alloc it all.
+	cdb_->length[0] = 0xff;
+	cdb_->length[1] = 0xff;
+	cdb_->length[2] = 0xff;
+	cdb_->length[3] = 0xff;
+	io->scsiio.cdb_len = sizeof(cdb);
+	memcpy(io->scsiio.cdb, cdb, sizeof(cdb));
+	io->io_hdr.flags |= CTL_FLAG_DATA_IN;
+	r = ioctl(fd, CTL_IO, io);
+	if (r == -1)
+		err(1, "ioctl");
+	if ((io->io_hdr.status & CTL_STATUS_MASK) == CTL_SUCCESS) {
+		return (0);
+	} else {
+		return (1);
+	}
+}