QEMU tries to change the "threads" option even if it was explicitly set in the command-line, and it shouldn't do that.
The right thing to do when all options (cpus, sockets, cores, threds) are explicitly set is to sanity check them and abort in case they don't make sense (i.e. when sockets*cores*threads < cpus). Signed-off-by: Eduardo Habkost <ehabk...@redhat.com> --- vl.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/vl.c b/vl.c index 2ed8b07..8880a4e 100644 --- a/vl.c +++ b/vl.c @@ -1287,8 +1287,14 @@ static void smp_parse(QemuOpts *opts) } else if (cores == 0) { threads = threads > 0 ? threads : 1; cores = cpus / (sockets * threads); - } else { + } else if (threads == 0) { threads = cpus / (cores * sockets); + } else if (sockets * cores * threads < cpus) { + fprintf(stderr, "cpu topology: error: " + "sockets (%u) * cores (%u) * threads (%u) < " + "smp_cpus (%u)\n", + sockets, cores, threads, cpus); + exit(1); } max_cpus = qemu_opt_get_number(opts, "maxcpus", 0); -- 1.9.3