We only set smp number at config time, other than it has no effect. Also limit the number value below 255, since qemu can't support that. Below is the reproduce from https://bugzilla.redhat.com/show_bug.cgi?id=795322 Signed-off-by: Wanlong Gao <gaowanlong(a)cn.fujitsu.com&gt; --- src/guestfs.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-) diff --git a/src/guestfs.c b/src/guestfs.c index 3607eaa..3dcdf27 100644 --- a/src/guestfs.c +++ b/src/guestfs.c @@ -794,7 +794,12 @@ guestfs__get_pgroup (guestfs_h *g) int guestfs__set_smp (guestfs_h *g, int v) { - if (v >= 1) { + if (g->state != CONFIG) + return 0; + if (v > 255) { + error (g, "Unsupported number of smp cpus: %d", v); + return -1; + } else if (v >= 1) { g->smp = v; return 0; } else { -- 1.7.9