On Thu, Nov 20, 2025 at 09:44:43PM -0800, Bobby Eshleman wrote:
>From: Bobby Eshleman <bobbyeshleman@meta.com>
>
>Add tests to verify CID collision rules across different vsock namespace
>modes.
>
>1. Two VMs with the same CID cannot start in different global namespaces
> (ns_global_same_cid_fails)
>2. Two VMs with the same CID can start in different local namespaces
> (ns_local_same_cid_ok)
>3. VMs with the same CID can coexist when one is in a global namespace
> and another is in a local namespace (ns_global_local_same_cid_ok and
> ns_local_global_same_cid_ok)
>
>The tests ns_global_local_same_cid_ok and ns_local_global_same_cid_ok
>make sure that ordering does not matter.
>
>The tests use a shared helper function namespaces_can_boot_same_cid()
>that attempts to start two VMs with identical CIDs in the specified
>namespaces and verifies whether VM initialization failed or succeeded.
>
>Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
>---
>Changes in v11:
>- check vm_start() rc in namespaces_can_boot_same_cid() (Stefano)
>- fix ns_local_same_cid_ok() to use local0 and local1 instead of reusing
> local0 twice. This check should pass, ensuring local namespaces do not
> collide (Stefano)
>---
> tools/testing/selftests/vsock/vmtest.sh | 78 +++++++++++++++++++++++++++++++++
> 1 file changed, 78 insertions(+)
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
>
>diff --git a/tools/testing/selftests/vsock/vmtest.sh b/tools/testing/selftests/vsock/vmtest.sh
>index 2e077e8a1777..f84da1e8ad14 100755
>--- a/tools/testing/selftests/vsock/vmtest.sh
>+++ b/tools/testing/selftests/vsock/vmtest.sh
>@@ -51,6 +51,10 @@ readonly TEST_NAMES=(
> ns_host_vsock_ns_mode_ok
> ns_host_vsock_ns_mode_write_once_ok
> ns_vm_local_mode_rejected
>+ ns_global_same_cid_fails
>+ ns_local_same_cid_ok
>+ ns_global_local_same_cid_ok
>+ ns_local_global_same_cid_ok
> )
> readonly TEST_DESCS=(
> # vm_server_host_client
>@@ -70,6 +74,18 @@ readonly TEST_DESCS=(
>
> # ns_vm_local_mode_rejected
> "Test that guest VM with G2H transport cannot set namespace mode to 'local'"
>+
>+ # ns_global_same_cid_fails
>+ "Check QEMU fails to start two VMs with same CID in two different global namespaces."
>+
>+ # ns_local_same_cid_ok
>+ "Check QEMU successfully starts two VMs with same CID in two different local namespaces."
>+
>+ # ns_global_local_same_cid_ok
>+ "Check QEMU successfully starts one VM in a global ns and then another VM in a local ns with the same CID."
>+
>+ # ns_local_global_same_cid_ok
>+ "Check QEMU successfully starts one VM in a local ns and then another VM in a global ns with the same CID."
> )
>
> readonly USE_SHARED_VM=(
>@@ -581,6 +597,68 @@ test_ns_host_vsock_ns_mode_ok() {
> return "${KSFT_PASS}"
> }
>
>+namespaces_can_boot_same_cid() {
>+ local ns0=$1
>+ local ns1=$2
>+ local pidfile1 pidfile2
>+ local rc
>+
>+ pidfile1="$(create_pidfile)"
>+
>+ # The first VM should be able to start. If it can't then we have
>+ # problems and need to return non-zero.
>+ if ! vm_start "${pidfile1}" "${ns0}"; then
>+ return 1
>+ fi
>+
>+ pidfile2="$(create_pidfile)"
>+ vm_start "${pidfile2}" "${ns1}"
>+ rc=$?
>+ terminate_pidfiles "${pidfile1}" "${pidfile2}"
>+
>+ return "${rc}"
>+}
>+
>+test_ns_global_same_cid_fails() {
>+ init_namespaces
>+
>+ if namespaces_can_boot_same_cid "global0" "global1"; then
>+ return "${KSFT_FAIL}"
>+ fi
>+
>+ return "${KSFT_PASS}"
>+}
>+
>+test_ns_local_global_same_cid_ok() {
>+ init_namespaces
>+
>+ if namespaces_can_boot_same_cid "local0" "global0"; then
>+ return "${KSFT_PASS}"
>+ fi
>+
>+ return "${KSFT_FAIL}"
>+}
>+
>+test_ns_global_local_same_cid_ok() {
>+ init_namespaces
>+
>+ if namespaces_can_boot_same_cid "global0" "local0"; then
>+ return "${KSFT_PASS}"
>+ fi
>+
>+ return "${KSFT_FAIL}"
>+}
>+
>+test_ns_local_same_cid_ok() {
>+ init_namespaces
>+
>+ if namespaces_can_boot_same_cid "local0" "local1"; then
>+ return "${KSFT_PASS}"
>+ fi
>+
>+ return "${KSFT_FAIL}"
>+}
>+
> test_ns_host_vsock_ns_mode_write_once_ok() {
> for mode in "${NS_MODES[@]}"; do
> local ns="${mode}0"
>
>--
>2.47.3
>