+ if (qemu_supports (g, "-machine")) {
+ add_cmdline (g, "-machine");
+#if QEMU_MACHINE_TYPE_IS_BROKEN
+ /* Workaround for qemu 0.15: We have to add the '[type=]pc'
+ * since there is no default. This is not a permanent solution
+ * because this only works on PC-like hardware. Other platforms
+ * like ppc would need a different machine type.
+ *
+ * This bug is fixed in qemu commit 2645c6dcaf6ea2a51a, and was
+ * not a problem in qemu < 0.15.
+ */
+ add_cmdline (g, "pc,accel=kvm:tcg");
+#else
+ add_cmdline (g, "accel=kvm:tcg");
+#endif
+ } else {
+ /* qemu sometimes needs this option to enable hardware
+ * virtualization, but some versions of 'qemu-kvm' will use KVM
+ * regardless (even where this option appears in the help text).
+ * It is rumoured that there are versions of qemu where supplying
+ * this option when hardware virtualization is not available will
+ * cause qemu to fail, so we we have to check at least that
+ * /dev/kvm is openable. That's not reliable, since /dev/kvm
+ * might be openable by qemu but not by us (think: SELinux) in
+ * which case the user would not get hardware virtualization,
+ * although at least shouldn't fail. A giant clusterfuck with the
+ * qemu command line, again.
+ */
+ if (qemu_supports (g, "-enable-kvm") &&
+ is_openable (g, "/dev/kvm", O_RDWR))
+ add_cmdline (g, "-enable-kvm");
+ }