Re: [PATCH for-6.1 v2] machine: Disallow specifying topology parameters as zero

[wangyanan (Y)]

Hi Cleber,

On 2021/7/23 6:25, Cleber Rosa wrote:
> Yanan Wang writes:
>
> > In the SMP configuration, we should either specify a topology
> > parameter with a reasonable value (equal to or greater than 1)
> > or just leave it omitted and QEMU will calculate its value.
> > Configurations which explicitly specify the topology parameters
> > as zero like "sockets=0" are meaningless, so disallow them.
> >
> > However, the commit 1e63fe685804d
> > (machine: pass QAPI struct to mc->smp_parse) has documented that
> > '0' has the same semantics as omitting a parameter in the qapi
> > comment for SMPConfiguration. So this patch fixes the doc and
> > also adds the corresponding sanity check in the smp parsers.
> >
> > Suggested-by: Andrew Jones <drjones@redhat.com>
> > Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
> > ---
> >   hw/core/machine.c | 14 ++++++++++++++
> >   qapi/machine.json |  6 +++---
> >   qemu-options.hx   | 12 +++++++-----
> >   3 files changed, 24 insertions(+), 8 deletions(-)
> Hi Yanan,
>
> This looks somewhat similar to this very old patch of mine:
>
>     https://mail.gnu.org/archive/html/qemu-devel/2020-10/msg03039.html
>
> I'm putting a reference here because I believe the test can be salvaged
> and slightly adapted for this patch of yours.
>
> Let me know if I can help anyhow.
Thanks for this.
I was introducing an unit test for the smp parsing in [1], in which all
possible valid and invalid smp configs were covered, and actually the
"parameter=0" stuff was also covered. You can have a look, and
suggestions are welcome. I'm not sure we need two different tests
for the same part. :)

[1] 
20210719032043.25416-12-wangyanan55@huawei.com/">https://lore.kernel.org/qemu-devel/20210719032043.25416-12-wangyanan55@huawei.com/

Thanks,
Yanan
.