Autodetect KVM

Autodetect KVM by using the 'kvm-ok' command line tool. This has two benefits:

Firstly, it improves the UX of run-qemu-ota when working on machines without
KVM (e.g. AWS). Previously, people had to use the --no-kvm option in these
cases.

Secondary, it makes oe-selftest usable on machines without KVM.  Our tests call
run-qemu-ota, and we want to able to run them on machines without KVM.

2 files changed, 15 insertions, 2 deletions

diff --git a/scripts/qemucommand.py b/scripts/qemucommand.py
index a75ffb6..82a9540 100644
--- a/scripts/qemucommand.py
+++ b/scripts/qemucommand.py
@@ -2,6 +2,7 @@ from os.path import exists, join, realpath, abspath
 from os import listdir
 import random
 import socket
+from subprocess import check_output, CalledProcessError
 
 EXTENSIONS = {
     'intel-corei7-64': 'wic',
@@ -67,7 +68,15 @@ class QemuCommand(object):
             self.mac_address = random_mac()
         self.serial_port = find_local_port(8990)
         self.ssh_port = find_local_port(2222)
-        self.kvm = not args.no_kvm
+        if args.kvm is None:
+            # Autodetect KVM using 'kvm-ok'
+            try:
+                check_output(['kvm-ok'])
+                self.kvm = True
+            except CalledProcessError:
+                self.kvm = False
+        else:
+            self.kvm = args.kvm
         self.gui = not args.no_gui
         self.gdb = args.gdb
         self.pcap = args.pcap
diff --git a/scripts/run-qemu-ota b/scripts/run-qemu-ota
index 8e25197..56e4fbc 100755
--- a/scripts/run-qemu-ota
+++ b/scripts/run-qemu-ota
@@ -21,7 +21,11 @@ def main():
                              'OSTREE_BOOTLOADER = "grub" and OVMF.fd firmware to be installed (try "apt install ovmf")',
                         action='store_true')
     parser.add_argument('--machine', default=None, help="Target MACHINE")
-    parser.add_argument('--no-kvm', help='Disable KVM in QEMU', action='store_true')
+    kvm_group = parser.add_argument_group()
+    kvm_group.add_argument('--force-kvm', help='Force use of KVM (default is to autodetect)',
+                           dest='kvm', action='store_true', default=None)
+    kvm_group.add_argument('--no-kvm', help='Disable KVM in QEMU',
+                           dest='kvm', action='store_false')
     parser.add_argument('--no-gui', help='Disable GUI', action='store_true')
     parser.add_argument('--gdb', help='Export gdbserver port 2159 from the image', action='store_true')
     parser.add_argument('--pcap', default=None, help='Dump all network traffic')