[PATCH 4/5] iotests: Skip "make check-block" if QEMU does not support virtio-blk

[Thomas Huth <thuth@redhat.com>]

The next patch is going to add some python-based tests to the "auto"
group, and these tests require virtio-blk to work properly. Running
iotests without virtio-blk likely does not make too much sense anyway,
so instead of adding a check for the availability of virtio-blk to each
and every test (which does not sound very appealing), let's rather add
a check for this at the top level in the check-block.sh script instead
(so that it is possible to run "make check" without the "check-block"
part for qemu-system-tricore for example).

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 tests/check-block.sh | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/tests/check-block.sh b/tests/check-block.sh
index 679aedec50..7582347ec2 100755
--- a/tests/check-block.sh
+++ b/tests/check-block.sh
@@ -26,10 +26,24 @@ if grep -q "CFLAGS.*-fsanitize" config-host.mak 2>/dev/null ; then
     exit 0
 fi
 
-if [ -z "$(find . -name 'qemu-system-*' -print)" ]; then
+if [ -n "$QEMU_PROG" ]; then
+    qemu_prog="$QEMU_PROG"
+else
+    for binary in *-softmmu/qemu-system-* ; do
+        if [ -x "$binary" ]; then
+            qemu_prog="$binary"
+            break
+        fi
+    done
+fi
+if [ -z "$qemu_prog" ]; then
     echo "No qemu-system binary available ==> Not running the qemu-iotests."
     exit 0
 fi
+if ! "$qemu_prog" -M none -device help | grep virtio-blk >/dev/null 2>&1 ; then
+    echo "$qemu_prog does not support virtio-blk ==> Not running the qemu-iotests."
+    exit 0
+fi
 
 if ! command -v bash >/dev/null 2>&1 ; then
     echo "bash not available ==> Not running the qemu-iotests."
-- 
2.18.1