test: rework run_qemu

It tries to find a suitable QEMU binary and will use KVM if present.
We can now configure QEMU from outside with 4 variables :
  - $QEMU_BIN : path to QEMU's binary
  - $KERNEL_APPEND : arguments appended to kernel cmdline
  - $KERNEL_BIN : path to a kernel
    Default /boot/vmlinuz-$KERNEL_VER
  - $INITRD : path to an initramfs
    Default /boot/initramfs-${KERNEL_VER}.img
  - $QEMU_SMP : number of CPU simulated by QEMU.
    Default 1

(from Alexander Graf's script: http://www.spinics.net/lists/kvm/msg72389.html)

1 files changed, 16 insertions, 3 deletions

diff --git a/test/README.testsuite b/test/README.testsuite
index 54d0eaac50..2ae85a2ce1 100644
--- a/test/README.testsuite
+++ b/test/README.testsuite
@@ -25,11 +25,24 @@ $ make all
 $ cd test/TEST-01-BASIC
 $ sudo make clean setup run
 
+QEMU
+====
+
 If you want to log in the testsuite virtual machine, you can specify
-additional kernel command line parameter with $DEBUGFAIL.
+additional kernel command line parameter with $KERNEL_APPEND.
 
-$ sudo make DEBUGFAIL="systemd.unit=multi-user.target" clean setup run
+$ sudo make KERNEL_APPEND="systemd.unit=multi-user.target" clean setup run
 
 you can even skip the "clean" and "setup" if you want to run the machine again.
 
-$ sudo make DEBUGFAIL="systemd.unit=multi-user.target" run
+$ sudo make KERNEL_APPEND="systemd.unit=multi-user.target" run
+
+You can specify a different kernel and initramfs with $KERNEL_BIN and $INITRD.
+(Fedora's default kernel path and initramfs are used by default)
+
+$ sudo make KERNEL_BIN=/boot/vmlinuz-foo INITRD=/boot/initramfs-bar clean check
+
+A script will try to find your QEMU binary. If you want to specify a different
+one you can use $QEMU_BIN.
+
+$ sudo make QEMU_BIN=/path/to/qemu/qemu-kvm clean check