[PATCH for-6.1 v2 0/1] machine: Disallow specifying topology parameters as zero

[PATCH for-6.1 v2 0/1] machine: Disallow specifying topology parameters as zero

[Yanan Wang]

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.

This patch originly comes form [1], and it was suggested that
this patch fixing the doc should be sent for 6.1 to avoid a
deprecation process in the future.

[1] https://lore.kernel.org/qemu-devel/YPWsThPiZa3mF+zp@redhat.com/

v1->v2:
- move the check to machine_set_smp
- update qemu-option.hx
- v1: https://lore.kernel.org/qemu-devel/20210722021512.2600-1-wangyanan55@huawei.com/

Yanan Wang (1):
  machine: Disallow specifying topology parameters as zero

 hw/core/machine.c | 14 ++++++++++++++
 qapi/machine.json |  6 +++---
 qemu-options.hx   | 12 +++++++-----
 3 files changed, 24 insertions(+), 8 deletions(-)

-- 
2.19.1

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

[Yanan Wang]

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(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 775add0795..db129d937b 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -829,6 +829,20 @@ static void machine_set_smp(Object *obj, Visitor *v, const char *name,
         return;
     }
 
+    /*
+     * The topology parameters must be specified equal to or great than one
+     * or just omitted, explicit configuration like "cpus=0" is not allowed.
+     */
+    if ((config->has_cpus && config->cpus == 0) ||
+        (config->has_sockets && config->sockets == 0) ||
+        (config->has_dies && config->dies == 0) ||
+        (config->has_cores && config->cores == 0) ||
+        (config->has_threads && config->threads == 0) ||
+        (config->has_maxcpus && config->maxcpus == 0)) {
+        error_setg(errp, "parameters must be equal to or greater than one if provided");
+        goto out_free;
+    }
+
     mc->smp_parse(ms, config, errp);
     if (errp) {
         goto out_free;
diff --git a/qapi/machine.json b/qapi/machine.json
index c3210ee1fb..9272cb3cf8 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -1288,8 +1288,8 @@
 ##
 # @SMPConfiguration:
 #
-# Schema for CPU topology configuration.  "0" or a missing value lets
-# QEMU figure out a suitable value based on the ones that are provided.
+# Schema for CPU topology configuration. A missing value lets QEMU
+# figure out a suitable value based on the ones that are provided.
 #
 # @cpus: number of virtual CPUs in the virtual machine
 #
@@ -1297,7 +1297,7 @@
 #
 # @dies: number of dies per socket in the CPU topology
 #
-# @cores: number of cores per thread in the CPU topology
+# @cores: number of cores per die in the CPU topology
 #
 # @threads: number of threads per core in the CPU topology
 #
diff --git a/qemu-options.hx b/qemu-options.hx
index 99ed5ec5f1..b0168f8c48 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -223,11 +223,13 @@ SRST
     of computing the CPU maximum count.
 
     Either the initial CPU count, or at least one of the topology parameters
-    must be specified. Values for any omitted parameters will be computed
-    from those which are given. Historically preference was given to the
-    coarsest topology parameters when computing missing values (ie sockets
-    preferred over cores, which were preferred over threads), however, this
-    behaviour is considered liable to change.
+    must be specified. The specified parameters must be equal to or great
+    than one, explicit configuration like "cpus=0" is not allowed. Values
+    for any omitted parameters will be computed from those which are given.
+    Historically preference was given to the coarsest topology parameters
+    when computing missing values (ie sockets preferred over cores, which
+    were preferred over threads), however, this behaviour is considered
+    liable to change.
 ERST
 
 DEF("numa", HAS_ARG, QEMU_OPTION_numa,
-- 
2.19.1

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

[Daniel P. Berrangé]

On Thu, Jul 22, 2021 at 11:43:26PM +0800, Yanan Wang wrote:
> 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(-)
> 
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index 775add0795..db129d937b 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -829,6 +829,20 @@ static void machine_set_smp(Object *obj, Visitor *v, const char *name,
>          return;
>      }
>  
> +    /*
> +     * The topology parameters must be specified equal to or great than one
> +     * or just omitted, explicit configuration like "cpus=0" is not allowed.
> +     */
> +    if ((config->has_cpus && config->cpus == 0) ||
> +        (config->has_sockets && config->sockets == 0) ||
> +        (config->has_dies && config->dies == 0) ||
> +        (config->has_cores && config->cores == 0) ||
> +        (config->has_threads && config->threads == 0) ||
> +        (config->has_maxcpus && config->maxcpus == 0)) {
> +        error_setg(errp, "parameters must be equal to or greater than one if provided");

I'd suggest a slight tweak since when seen it lacks context:

$ ./qemu-system-x86_64 -smp 4,cores=0,sockets=2
qemu-system-x86_64: parameters must be equal to or greater than one if provided


    error_setg(errp, "CPU topology parameters must be equal to or greater than one if provided");



> diff --git a/qemu-options.hx b/qemu-options.hx
> index 99ed5ec5f1..b0168f8c48 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -223,11 +223,13 @@ SRST
>      of computing the CPU maximum count.
>  
>      Either the initial CPU count, or at least one of the topology parameters
> -    must be specified. Values for any omitted parameters will be computed
> -    from those which are given. Historically preference was given to the
> -    coarsest topology parameters when computing missing values (ie sockets
> -    preferred over cores, which were preferred over threads), however, this
> -    behaviour is considered liable to change.
> +    must be specified. The specified parameters must be equal to or great

s/great/greater/

> +    than one, explicit configuration like "cpus=0" is not allowed. Values
> +    for any omitted parameters will be computed from those which are given.
> +    Historically preference was given to the coarsest topology parameters
> +    when computing missing values (ie sockets preferred over cores, which
> +    were preferred over threads), however, this behaviour is considered
> +    liable to change.
>  ERST


If you make the text changes, then feel free to add this when posting v2:

 Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
 Tested-by: Daniel P. Berrangé <berrange@redhat.com>
 


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

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

[Markus Armbruster]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Thu, Jul 22, 2021 at 11:43:26PM +0800, Yanan Wang wrote:
>> 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(-)
>> 
>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>> index 775add0795..db129d937b 100644
>> --- a/hw/core/machine.c
>> +++ b/hw/core/machine.c
>> @@ -829,6 +829,20 @@ static void machine_set_smp(Object *obj, Visitor *v, const char *name,
>>          return;
>>      }
>>  
>> +    /*
>> +     * The topology parameters must be specified equal to or great than one
>> +     * or just omitted, explicit configuration like "cpus=0" is not allowed.
>> +     */
>> +    if ((config->has_cpus && config->cpus == 0) ||
>> +        (config->has_sockets && config->sockets == 0) ||
>> +        (config->has_dies && config->dies == 0) ||
>> +        (config->has_cores && config->cores == 0) ||
>> +        (config->has_threads && config->threads == 0) ||
>> +        (config->has_maxcpus && config->maxcpus == 0)) {
>> +        error_setg(errp, "parameters must be equal to or greater than one if provided");
>
> I'd suggest a slight tweak since when seen it lacks context:
>
> $ ./qemu-system-x86_64 -smp 4,cores=0,sockets=2
> qemu-system-x86_64: parameters must be equal to or greater than one if provided
>
>
>     error_setg(errp, "CPU topology parameters must be equal to or greater than one if provided");

Let's scratch "if provided".

I'd replace "must be equal to or greater than one" by "must be
positive", or maybe "must be greater than zero".

>> diff --git a/qemu-options.hx b/qemu-options.hx
>> index 99ed5ec5f1..b0168f8c48 100644
>> --- a/qemu-options.hx
>> +++ b/qemu-options.hx
>> @@ -223,11 +223,13 @@ SRST
>>      of computing the CPU maximum count.
>>  
>>      Either the initial CPU count, or at least one of the topology parameters
>> -    must be specified. Values for any omitted parameters will be computed
>> -    from those which are given. Historically preference was given to the
>> -    coarsest topology parameters when computing missing values (ie sockets
>> -    preferred over cores, which were preferred over threads), however, this
>> -    behaviour is considered liable to change.
>> +    must be specified. The specified parameters must be equal to or great
>
> s/great/greater/
>
>> +    than one, explicit configuration like "cpus=0" is not allowed. Values

"positive" again.

>> +    for any omitted parameters will be computed from those which are given.
>> +    Historically preference was given to the coarsest topology parameters
>> +    when computing missing values (ie sockets preferred over cores, which
>> +    were preferred over threads), however, this behaviour is considered
>> +    liable to change.
>>  ERST
>
>
> If you make the text changes, then feel free to add this when posting v2:
>
>  Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
>  Tested-by: Daniel P. Berrangé <berrange@redhat.com>
>  
>
>
> Regards,
> Daniel

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

[wangyanan (Y)]

On 2021/7/23 16:02, Markus Armbruster wrote:
> Daniel P. Berrangé <berrange@redhat.com> writes:
>
>> On Thu, Jul 22, 2021 at 11:43:26PM +0800, Yanan Wang wrote:
>>> 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(-)
>>>
>>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>>> index 775add0795..db129d937b 100644
>>> --- a/hw/core/machine.c
>>> +++ b/hw/core/machine.c
>>> @@ -829,6 +829,20 @@ static void machine_set_smp(Object *obj, Visitor *v, const char *name,
>>>           return;
>>>       }
>>>   
>>> +    /*
>>> +     * The topology parameters must be specified equal to or great than one
>>> +     * or just omitted, explicit configuration like "cpus=0" is not allowed.
>>> +     */
>>> +    if ((config->has_cpus && config->cpus == 0) ||
>>> +        (config->has_sockets && config->sockets == 0) ||
>>> +        (config->has_dies && config->dies == 0) ||
>>> +        (config->has_cores && config->cores == 0) ||
>>> +        (config->has_threads && config->threads == 0) ||
>>> +        (config->has_maxcpus && config->maxcpus == 0)) {
>>> +        error_setg(errp, "parameters must be equal to or greater than one if provided");
>> I'd suggest a slight tweak since when seen it lacks context:
>>
>> $ ./qemu-system-x86_64 -smp 4,cores=0,sockets=2
>> qemu-system-x86_64: parameters must be equal to or greater than one if provided
>>
>>
>>      error_setg(errp, "CPU topology parameters must be equal to or greater than one if provided");
> Let's scratch "if provided".
>
> I'd replace "must be equal to or greater than one" by "must be
> positive", or maybe "must be greater than zero".
How about we use "must be greater than zero" ?
After a grep search of these two sentences in QEMU, they both show up
in several places. "must be positive" always reports an invalid value that
is "< 0". While the check in this patch actually reject an invalid zero 
value.
>>> diff --git a/qemu-options.hx b/qemu-options.hx
>>> index 99ed5ec5f1..b0168f8c48 100644
>>> --- a/qemu-options.hx
>>> +++ b/qemu-options.hx
>>> @@ -223,11 +223,13 @@ SRST
>>>       of computing the CPU maximum count.
>>>   
>>>       Either the initial CPU count, or at least one of the topology parameters
>>> -    must be specified. Values for any omitted parameters will be computed
>>> -    from those which are given. Historically preference was given to the
>>> -    coarsest topology parameters when computing missing values (ie sockets
>>> -    preferred over cores, which were preferred over threads), however, this
>>> -    behaviour is considered liable to change.
>>> +    must be specified. The specified parameters must be equal to or great
>> s/great/greater/
>>
>>> +    than one, explicit configuration like "cpus=0" is not allowed. Values
> "positive" again.
Thanks,
Yanan
>>> +    for any omitted parameters will be computed from those which are given.
>>> +    Historically preference was given to the coarsest topology parameters
>>> +    when computing missing values (ie sockets preferred over cores, which
>>> +    were preferred over threads), however, this behaviour is considered
>>> +    liable to change.
>>>   ERST
>>
>> If you make the text changes, then feel free to add this when posting v2:
>>
>>   Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
>>   Tested-by: Daniel P. Berrangé <berrange@redhat.com>
>>   
>>
>>
>> Regards,
>> Daniel
> .

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

[Cornelia Huck]

On Fri, Jul 23 2021, "wangyanan (Y)" <wangyanan55@huawei.com> wrote:

> On 2021/7/23 16:02, Markus Armbruster wrote:
>> Daniel P. Berrangé <berrange@redhat.com> writes:
>>
>>> On Thu, Jul 22, 2021 at 11:43:26PM +0800, Yanan Wang wrote:
>>>> +    /*
>>>> +     * The topology parameters must be specified equal to or great than one
>>>> +     * or just omitted, explicit configuration like "cpus=0" is not allowed.
>>>> +     */
>>>> +    if ((config->has_cpus && config->cpus == 0) ||
>>>> +        (config->has_sockets && config->sockets == 0) ||
>>>> +        (config->has_dies && config->dies == 0) ||
>>>> +        (config->has_cores && config->cores == 0) ||
>>>> +        (config->has_threads && config->threads == 0) ||
>>>> +        (config->has_maxcpus && config->maxcpus == 0)) {
>>>> +        error_setg(errp, "parameters must be equal to or greater than one if provided");
>>> I'd suggest a slight tweak since when seen it lacks context:
>>>
>>> $ ./qemu-system-x86_64 -smp 4,cores=0,sockets=2
>>> qemu-system-x86_64: parameters must be equal to or greater than one if provided
>>>
>>>
>>>      error_setg(errp, "CPU topology parameters must be equal to or greater than one if provided");
>> Let's scratch "if provided".
>>
>> I'd replace "must be equal to or greater than one" by "must be
>> positive", or maybe "must be greater than zero".
> How about we use "must be greater than zero" ?
> After a grep search of these two sentences in QEMU, they both show up
> in several places. "must be positive" always reports an invalid value that
> is "< 0". While the check in this patch actually reject an invalid zero 
> value.

Of the two, I'd prefer "greater than zero".

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

[Andrew Jones]

On Thu, Jul 22, 2021 at 11:43:26PM +0800, Yanan Wang wrote:
> 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(-)

With Daniel's suggested changes for v3

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

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

[Cleber Rosa]

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,
- Cleber.

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

Thanks,
Yanan
.

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

[Cleber Rosa]

wangyanan (Y) writes:

> 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. :)
>

Right, I only saw the other series later.  Nice work there!

- Cleber.