show kernel messages in verbose mode

skips using "quiet" kernel parameter

introducing --verbose option

build

@@ -124,6 +124,9 @@ COPY_SOURCES_ASIS=
 RECIPE_BUILD_START_TIME=
 CCACHE_SETUP_START_TIME=
 
+# set all verbose modes to off by default
+BUILD_VERBOSE_VM=
+
 # This is for insserv
 export YAST_IS_RUNNING=instsys
 # https://github.com/systemd/systemd/blob/master/docs/ENVIRONMENT.md
@@ -333,6 +336,10 @@ Known Parameters:
   --emulator-script SCRIPT
               specify another emulator instead of emulator.sh
 
+  --verbose CLASS
+              Verbose output, CLASS can be 'all' or a specific one:
+                vm: includes kernel and initrd messages
+
   --vm-type TYPE
               Use virtual machine instead of chroot
               TYPE is one of xen|kvm|uml|qemu|lxc|zvm|openstack|ec2|docker|pvm|nspawn
@@ -1240,6 +1247,21 @@ while test -n "$1"; do
 	RSYNCDEST=$ARG
 	shift
       ;;
+      -verbose)
+	needarg
+        case "$ARGS" in
+        all)
+            BUILD_VERBOSE_VM=true
+            ;;
+        vm)
+            BUILD_VERBOSE_VM=true
+            ;;
+        *)
+            echo "WARNING: unknown verbose option $ARGS"
+            ;;
+        esac
+	shift
+      ;;
       -uid)
 	needarg
 	if test -n "${ARG//[0-9:]/}" ; then

build-vm

@@ -25,7 +25,7 @@
 # so disabling spectre/meltdown mitigations doesn't hurt security and gains performance
 vm_linux_kernel_parameter="mitigations=off"
 # Make sure that dodgy kernels fail quickly and early
-vm_linux_always_append="oops=panic panic=1 quiet"
+vm_linux_always_append="oops=panic panic=1"
 
 # guest visible devices
 VM_ROOTDEV=/dev/hda1
@@ -101,6 +101,7 @@ vm_detach_swap() {
 }
 
 vm_fixup() {
+    test -z "$BUILD_VERBOSE_VM" && vm_linux_always_append="$vm_linux_always_append quiet"
     vm_fixup_$VM_TYPE "$@"
 }