[PATCH net-next] selftests/vsock: auto-detect kernel for guest VMs

[PATCH net-next] selftests/vsock: auto-detect kernel for guest VMs

[Bobby Eshleman]

From: Bobby Eshleman <bobbyeshleman@meta.com>

When running vmtest.sh inside a nested VM the running kernel may not be
installed on the filesystem at the standard /boot/ or /usr/lib/modules/
paths.

Previously, this would cause vng to fail with "does not exist" since it
could not find the kernel image. Instead, this patch uses --dry-run to
detect if the kernel is available. If not, then we fall back to the
kernel in the kernel source tree. If that fails, then we die.

This way runners, like NIPA, can use vng --run arch/x86/boot/bzImage to
setup an outer VM, and vmtest.sh will still do the right thing setting
up the inner VM.

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
 tools/testing/selftests/vsock/vmtest.sh | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/vsock/vmtest.sh b/tools/testing/selftests/vsock/vmtest.sh
index 86e338886b33..7247ac99cf33 100755
--- a/tools/testing/selftests/vsock/vmtest.sh
+++ b/tools/testing/selftests/vsock/vmtest.sh
@@ -441,6 +441,12 @@ vm_start() {
 
 	if [[ "${BUILD}" -eq 1 ]]; then
 		kernel_opt="${KERNEL_CHECKOUT}"
+	elif vng --run --dry-run &>/dev/null; then
+		kernel_opt=""
+	elif vng --run "${KERNEL_CHECKOUT}" --dry-run &>/dev/null; then
+		kernel_opt="${KERNEL_CHECKOUT}"
+	else
+		die "No suitable kernel found"
 	fi
 
 	if [[ "${ns}" != "init_ns" ]]; then

---
base-commit: 8f921f61005450589c0bc1a941a5ddde21d9aed9
change-id: 20260313-vsock-vmtest-autodetect-kernel-dd695ed3a710

Best regards,
-- 
Bobby Eshleman <bobbyeshleman@meta.com>