On Tue, Apr 05, 2016 at 06:38:36AM +0200, Kevin Wolf wrote: > Am 01.04.2016 um 13:20 hat Richard W.M. Jones geschrieben: > > > > My patch, plus the configuration and comments from your patch, > > combined. Plus I tested it with libguestfs boot-analysis and it works > > and is still fast. > > > > Integrating this so it happens automatically when the user adds > > -kernel on x86 seems quite complicated. The only way I could do it > > was by adding #ifdef defined(__x86_64__) etc to vl.c, which doesn't > > seem very nice. The problem is the machine type code doesn't know > > that you're using -kernel. > > I would actually find it rather surprising to get differernt BIOSes and > therefore potentially different behaviour for -kernel and for booting > from an image. Even if we made sure that Linux really never touches the > parts that you disable in bios-fast.bin, remember that -kernel is not > only for Linux, but for arbitrary kernels. > > Requiring an explicit -bios option like you do now seems to make most > sense to me: The default behaves the same as a normal boot, but if you > are one of the cases that do need that additional boot speed, you can do > that and consciously sacrifice the features.
OK so this reminds me of the second problem. How to detect what bioses are available, given a qemu binary. It would be nice if qemu had an option like: qemu -bios \? Of course we can try to scan /usr/share/qemu/bios.*, except that Fedora installs extra ROMs in /usr/share/seabios/ (I'm not exactly sure how qemu deals with those), and the path is different for other distros and other qemu binaries. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW