[Libguestfs] Adventures in building libguestfs on non-x86 architectures for Debian

[Hilko Bengen]

Hi,

things are progressing slowly, but I feel that eventually I'll be
getting there: supermin can be built on all Linux-based architectures
that are part of Debian/unstable[1] -- (except for sparc, but I'll
ignore that for now.) libguestfs on the other hand currently fails
launching the appliance (necessary for running tests) on everything but
x86 and mips.

Apparently, qemu-system-arm 2.0 as currently available through
Debian/unstable doesn't want to tell us anything about available devices
unless we specify a machine type. The patch below works around that
issue, but I haven't been able to run qemu-system-arm with a supermin
appliance on Debian's armhf porterbox so far: 100% CPU usage, no output
from the kernel.

For armel, there's no kernel with device tree blobs, so I think that I'll
need to use linux-image-versatile there or ignore armel altogether.

powerpc: qemu-system-ppc does not know about the "pseries" machine, I
have figured out that I need to use qemu-system-ppc64 for that. So far,
I haven't been able to manually boot a Supermin appliance using
qemu-system-ppc, either, though.

s390x does not seem to know about virtio-blk-pci.

Cheers,
-Hilko

[1] https://buildd.debian.org/status/package.php?p=supermin
[2] https://buildd.debian.org/status/package.php?p=libguestfs

diff --git a/src/launch-direct.c b/src/launch-direct.c
index 1460c56..2332368 100644
--- a/src/launch-direct.c
+++ b/src/launch-direct.c
@@ -1020,6 +1020,10 @@ test_qemu (guestfs_h *g, struct backend_direct_data *data)
   guestfs___cmd_add_arg (cmd3, g->hv);
   guestfs___cmd_add_arg (cmd3, "-display");
   guestfs___cmd_add_arg (cmd3, "none");
+#ifdef MACHINE_TYPE
+  guestfs___cmd_add_arg (cmd3, "-M");
+  guestfs___cmd_add_arg (cmd3, MACHINE_TYPE);
+#endif
   guestfs___cmd_add_arg (cmd3, "-machine");
   guestfs___cmd_add_arg (cmd3, "accel=kvm:tcg");
   guestfs___cmd_add_arg (cmd3, "-device");