ci: Make kernel image available in LAVA for KVM use cases

In order to run a VM (e.g. crosvm) through HWCI_TEST_SCRIPT on a LAVA
target, it's necessary to download a kernel image on the target device.

When HWCI_KVM is set to 'true', we can safely assume HWCI_TEST_SCRIPT
contains a command or the path to a script which expects the kernel
image to be available under /lava-files/${KERNEL_IMAGE_NAME}.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Reviewed-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15208>

.gitlab-ci/common/generate-env.sh

@@ -68,6 +68,8 @@ for var in \
     JOB_ARTIFACTS_BASE \
     JOB_RESULTS_PATH \
     JOB_ROOTFS_OVERLAY_PATH \
+    KERNEL_IMAGE_BASE_URL \
+    KERNEL_IMAGE_NAME \
     LD_LIBRARY_PATH \
     LP_NUM_THREADS \
     MESA_BASE_TAG \

.gitlab-ci/common/init-stage2.sh

@@ -12,9 +12,13 @@ set -ex
     echo -n $HWCI_KERNEL_MODULES | xargs -d, -n1 /usr/sbin/modprobe
 }
 
+#
 # Load the KVM module specific to the detected CPU virtualization extensions:
 # - vmx for Intel VT
 # - svm for AMD-V
+#
+# Additionally, download the kernel image to boot the VM via HWCI_TEST_SCRIPT.
+#
 if [ "$HWCI_KVM" = "true" ]; then
     unset KVM_KERNEL_MODULE
     grep -qs '\bvmx\b' /proc/cpuinfo && KVM_KERNEL_MODULE=kvm_intel || {
@@ -24,6 +28,10 @@ if [ "$HWCI_KVM" = "true" ]; then
     [ -z "${KVM_KERNEL_MODULE}" ] && \
         echo "WARNING: Failed to detect CPU virtualization extensions" || \
         modprobe ${KVM_KERNEL_MODULE}
+
+    mkdir -p /lava-files
+    wget -S --progress=dot:giga -O /lava-files/${KERNEL_IMAGE_NAME} \
+        "${KERNEL_IMAGE_BASE_URL}/${KERNEL_IMAGE_NAME}"
 fi
 
 # Fix prefix confusion: the build installs to $CI_PROJECT_DIR, but we expect