test: support disabling KVM by setting NO_KVM

KVM fails on the Ubuntu ppc64el autopkgtest runners:

```
$ /usr/bin/qemu-system-ppc64el -enable-kvm -cpu host [...]
ioctl(KVM_CREATE_VM) failed: 22 Invalid argument
PPC KVM module is not loaded. Try modprobe kvm_hv.
qemu-system-ppc64el: failed to initialize kvm: Invalid argument
$ modprobe kvm_hv
modprobe: ERROR: could not insert 'kvm_hv': No such device
```

Signed-off-by: Benjamin Drung <benjamin.drung@canonical.com>

diff --git a/test/run-qemu b/test/run-qemu
index 271f0019a2e431324e9ce7079cbcc50f931eaeda..41d458aabb9cd3ad81c2168dc671f628c4762cf7 100755 (executable)
--- a/test/run-qemu
+++ b/test/run-qemu
@@ -8,11 +8,11 @@ QEMU_CPU="${QEMU_CPU:-max}"
 
 [[ -x /usr/bin/qemu ]] && BIN=/usr/bin/qemu && ARGS=(-cpu "$QEMU_CPU")
 (lsmod | grep -q '^kqemu ') && BIN=/usr/bin/qemu && ARGS=(-kernel-kqemu -cpu host)
-[[ -c /dev/kvm && -x /usr/bin/kvm ]] && BIN=/usr/bin/kvm && ARGS=(-cpu host)
-[[ -c /dev/kvm && -x /usr/bin/qemu-kvm ]] && BIN=/usr/bin/qemu-kvm && ARGS=(-cpu host)
-[[ -c /dev/kvm && -x /usr/libexec/qemu-kvm ]] && BIN=/usr/libexec/qemu-kvm && ARGS=(-cpu host)
+[[ -z ${NO_KVM-} && -c /dev/kvm && -x /usr/bin/kvm ]] && BIN=/usr/bin/kvm && ARGS=(-cpu host)
+[[ -z ${NO_KVM-} && -c /dev/kvm && -x /usr/bin/qemu-kvm ]] && BIN=/usr/bin/qemu-kvm && ARGS=(-cpu host)
+[[ -z ${NO_KVM-} && -c /dev/kvm && -x /usr/libexec/qemu-kvm ]] && BIN=/usr/libexec/qemu-kvm && ARGS=(-cpu host)
 [[ -x "/usr/bin/qemu-system-${ARCH}" ]] && BIN="/usr/bin/qemu-system-${ARCH}" && ARGS=(-cpu "$QEMU_CPU")
-[[ -c /dev/kvm && -x "/usr/bin/qemu-system-${ARCH}" ]] && BIN="/usr/bin/qemu-system-${ARCH}" && ARGS=(-enable-kvm -cpu host)
+[[ -z ${NO_KVM-} && -c /dev/kvm && -x "/usr/bin/qemu-system-${ARCH}" ]] && BIN="/usr/bin/qemu-system-${ARCH}" && ARGS=(-enable-kvm -cpu host)
 
 [[ $BIN ]] || {
     echo "Could not find a working KVM or QEMU to test with!" >&2