Re: [Qemu-devel] [PATCH v2 3/3] vl: Don't silently change topology when all -smp options were set

[Andrew Jones <drjones@redhat.com>]

On Tue, Nov 11, 2014 at 04:50:56PM -0200, Eduardo Habkost wrote:
> 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 <ehabkost@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
>

Reviewed-by: Andrew Jones <drjones@redhat.com>