[PATCH v6 00/16] machine: smp parsing fixes and improvement

[PATCH v6 00/16] machine: smp parsing fixes and improvement

[Yanan Wang]

Rebased on upstream v6.1.0-rc4 with two more patches added.

This series introduces some fixes and improvement for the SMP parsing.
Behavior of specifying a CPU topology parameter as zero was implicitly
allowed but undocumented before, while now it's explicitly deprecated.
maxcpus is now uniformly used to calculate the omitted topology members.
It's also suggested that we should start to prefer cores over sockets
over threads on the newer machine types, which will make the computed
virtual topology more reflective of the real hardware.

In order to reduce code duplication and ease the code maintenance,
smp_parse() is converted into a generic enough parser for all arches,
so that the arch-specific ones (e.g. pc_smp_parse) can be removed.
It's also convenient to introduce more topology members to the generic
parser in the future.

A unit test for the SMP parsing is added. In the test, all possible
collections of the topology parameters and the corresponding expected
results are listed, including the valid and invalid ones. The preference
of sockets over cores and the preference of cores over sockets, and the
support of dies are also taken into consideration.

---

Changelogs:

v5->v6:
- deprecate "parameter=0" SMP configurations (patch #1 and #2 added)
- rebased on upstream v6.1.0-rc4
- v6: https://lore.kernel.org/qemu-devel/20210813023912.105880-1-wangyanan55@huawei.com/

v4->v5:
- refactor out the duplicated "threads == 0" case in patch #6 (Pankaj)
- pick up more R-b tags from v4 (thanks very much for the review!)
- v4: https://lore.kernel.org/qemu-devel/20210803080527.156556-1-wangyanan55@huawei.com/

v3->v4:
- put all the sanity check into the parser
- refine the unit test and add it back to the series
- add the R-b/A-b tags for the reviewed/acked patches
- v3: https://lore.kernel.org/qemu-devel/20210728034848.75228-1-wangyanan55@huawei.com/

v2->v3:
- apply the calculation improvement to smp_parse and pc_smp_parse
  separately and then convert the finally improved parsers into a
  generic one, so that patches can be reviewed separately.
- to ease review, drop the unit test part for a while until we have
  a good enough generic parser.
- send the patch "machine: Disallow specifying topology parameters as zero"
  for 6.1 separately.
- v2: https://lore.kernel.org/qemu-devel/20210719032043.25416-1-wangyanan55@huawei.com/

v1->v2:
- disallow "anything=0" in the smp configuration (Andrew)
- make function smp_parse() a generic helper for all arches
- improve the error reporting in the parser
- start to prefer cores over sockets since 6.2 (Daniel)
- add a unit test for the smp parsing (Daniel)
- v1: https://lore.kernel.org/qemu-devel/20210702100739.13672-1-wangyanan55@huawei.com/

---

Yanan Wang (16):
  docs/about/removed-features: Remove duplicated doc about -smp
  machine: Deprecate "parameter=0" SMP configurations
  machine: Minor refactor/fix for the smp parsers
  machine: Uniformly use maxcpus to calculate the omitted parameters
  machine: Set the value of cpus to match maxcpus if it's omitted
  machine: Improve the error reporting of smp parsing
  hw: Add compat machines for 6.2
  machine: Prefer cores over sockets in smp parsing since 6.2
  machine: Use ms instead of global current_machine in sanity-check
  machine: Tweak the order of topology members in struct CpuTopology
  machine: Make smp_parse generic enough for all arches
  machine: Remove smp_parse callback from MachineClass
  machine: Move smp_prefer_sockets to struct SMPCompatProps
  machine: Put all sanity-check in the generic SMP parser
  machine: Split out the smp parsing code
  tests/unit: Add a unit test for smp parsing

 MAINTAINERS                     |   2 +
 docs/about/deprecated.rst       |  15 +
 docs/about/removed-features.rst |  21 +-
 hw/arm/virt.c                   |  10 +-
 hw/core/machine-smp.c           | 200 ++++++++
 hw/core/machine.c               |  93 +---
 hw/core/meson.build             |   1 +
 hw/i386/pc.c                    |  66 +--
 hw/i386/pc_piix.c               |  15 +-
 hw/i386/pc_q35.c                |  14 +-
 hw/ppc/spapr.c                  |  16 +-
 hw/s390x/s390-virtio-ccw.c      |  15 +-
 include/hw/boards.h             |  27 +-
 include/hw/i386/pc.h            |   3 +
 qapi/machine.json               |   2 +-
 qemu-options.hx                 |  24 +-
 tests/unit/meson.build          |   1 +
 tests/unit/test-smp-parse.c     | 866 ++++++++++++++++++++++++++++++++
 18 files changed, 1205 insertions(+), 186 deletions(-)
 create mode 100644 hw/core/machine-smp.c
 create mode 100644 tests/unit/test-smp-parse.c

--
2.19.1

[PATCH v6 01/16] docs/about/removed-features: Remove duplicated doc about -smp

[Yanan Wang]

There are two places describing the same thing about deprecation
of invalid topologies of -smp CLI, so remove the duplicated one.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
---
 docs/about/removed-features.rst | 21 ++++-----------------
 1 file changed, 4 insertions(+), 17 deletions(-)

diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
index cbfa1a8e31..f5d6e2ea9c 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -194,7 +194,7 @@ by the ``tls-authz`` and ``sasl-authz`` options.
 The ``pretty=on|off`` switch has no effect for HMP monitors and
 its use is rejected.
 
-``-drive file=json:{...{'driver':'file'}}`` (removed 6.0)
+``-drive file=json:{...{'driver':'file'}}`` (removed in 6.0)
 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 The 'file' driver for drives is no longer appropriate for character or host
@@ -593,7 +593,7 @@ error when ``-u`` is not used.
 Command line options
 --------------------
 
-``-smp`` (invalid topologies) (removed 5.2)
+``-smp`` (invalid topologies) (removed in 5.2)
 '''''''''''''''''''''''''''''''''''''''''''
 
 CPU topology properties should describe whole machine topology including
@@ -606,7 +606,7 @@ Support for invalid topologies is removed, the user must ensure
 topologies described with -smp include all possible cpus, i.e.
 *sockets* * *cores* * *threads* = *maxcpus*.
 
-``-numa`` node (without memory specified) (removed 5.2)
+``-numa`` node (without memory specified) (removed in 5.2)
 '''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 Splitting RAM by default between NUMA nodes had the same issues as ``mem``
@@ -647,20 +647,7 @@ as ignored. Currently, users are responsible for making sure the backing storage
 specified with ``-mem-path`` can actually provide the guest RAM configured with
 ``-m`` and QEMU fails to start up if RAM allocation is unsuccessful.
 
-``-smp`` (invalid topologies) (removed 5.2)
-'''''''''''''''''''''''''''''''''''''''''''
-
-CPU topology properties should describe whole machine topology including
-possible CPUs.
-
-However, historically it was possible to start QEMU with an incorrect topology
-where *n* <= *sockets* * *cores* * *threads* < *maxcpus*,
-which could lead to an incorrect topology enumeration by the guest.
-Support for invalid topologies is removed, the user must ensure
-topologies described with -smp include all possible cpus, i.e.
-*sockets* * *cores* * *threads* = *maxcpus*.
-
-``-machine enforce-config-section=on|off`` (removed 5.2)
+``-machine enforce-config-section=on|off`` (removed in 5.2)
 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 The ``enforce-config-section`` property was replaced by the
-- 
2.19.1

Re: [PATCH v6 01/16] docs/about/removed-features: Remove duplicated doc about -smp

[Cornelia Huck]

On Thu, Aug 19 2021, Yanan Wang <wangyanan55@huawei.com> wrote:

> There are two places describing the same thing about deprecation
> of invalid topologies of -smp CLI, so remove the duplicated one.
>
> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
> ---
>  docs/about/removed-features.rst | 21 ++++-----------------
>  1 file changed, 4 insertions(+), 17 deletions(-)
>
> diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
> index cbfa1a8e31..f5d6e2ea9c 100644
> --- a/docs/about/removed-features.rst
> +++ b/docs/about/removed-features.rst
> @@ -194,7 +194,7 @@ by the ``tls-authz`` and ``sasl-authz`` options.
>  The ``pretty=on|off`` switch has no effect for HMP monitors and
>  its use is rejected.
>  
> -``-drive file=json:{...{'driver':'file'}}`` (removed 6.0)
> +``-drive file=json:{...{'driver':'file'}}`` (removed in 6.0)

I would not change this in this patch; while the cleanup looks fine,
there are some more instances and also e.g. things like x.y.z being used
sometimes, and it's probably better to clean that up via a separated patch.

>  '''''''''''''''''''''''''''''''''''''''''''''''''''''''''
>  
>  The 'file' driver for drives is no longer appropriate for character or host
> @@ -593,7 +593,7 @@ error when ``-u`` is not used.
>  Command line options
>  --------------------
>  
> -``-smp`` (invalid topologies) (removed 5.2)
> +``-smp`` (invalid topologies) (removed in 5.2)
>  '''''''''''''''''''''''''''''''''''''''''''
>  
>  CPU topology properties should describe whole machine topology including
> @@ -606,7 +606,7 @@ Support for invalid topologies is removed, the user must ensure
>  topologies described with -smp include all possible cpus, i.e.
>  *sockets* * *cores* * *threads* = *maxcpus*.
>  
> -``-numa`` node (without memory specified) (removed 5.2)
> +``-numa`` node (without memory specified) (removed in 5.2)
>  '''''''''''''''''''''''''''''''''''''''''''''''''''''''
>  
>  Splitting RAM by default between NUMA nodes had the same issues as ``mem``
> @@ -647,20 +647,7 @@ as ignored. Currently, users are responsible for making sure the backing storage
>  specified with ``-mem-path`` can actually provide the guest RAM configured with
>  ``-m`` and QEMU fails to start up if RAM allocation is unsuccessful.
>  
> -``-smp`` (invalid topologies) (removed 5.2)
> -'''''''''''''''''''''''''''''''''''''''''''
> -
> -CPU topology properties should describe whole machine topology including
> -possible CPUs.
> -
> -However, historically it was possible to start QEMU with an incorrect topology
> -where *n* <= *sockets* * *cores* * *threads* < *maxcpus*,
> -which could lead to an incorrect topology enumeration by the guest.
> -Support for invalid topologies is removed, the user must ensure
> -topologies described with -smp include all possible cpus, i.e.
> -*sockets* * *cores* * *threads* = *maxcpus*.

Actually removing the duplicated section looks fine.

> -
> -``-machine enforce-config-section=on|off`` (removed 5.2)
> +``-machine enforce-config-section=on|off`` (removed in 5.2)
>  ''''''''''''''''''''''''''''''''''''''''''''''''''''''''
>  
>  The ``enforce-config-section`` property was replaced by the

Re: [PATCH v6 01/16] docs/about/removed-features: Remove duplicated doc about -smp

[wangyanan (Y)]

On 2021/8/19 19:26, Cornelia Huck wrote:
> On Thu, Aug 19 2021, Yanan Wang <wangyanan55@huawei.com> wrote:
>
>> There are two places describing the same thing about deprecation
>> of invalid topologies of -smp CLI, so remove the duplicated one.
>>
>> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
>> ---
>>   docs/about/removed-features.rst | 21 ++++-----------------
>>   1 file changed, 4 insertions(+), 17 deletions(-)
>>
>> diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
>> index cbfa1a8e31..f5d6e2ea9c 100644
>> --- a/docs/about/removed-features.rst
>> +++ b/docs/about/removed-features.rst
>> @@ -194,7 +194,7 @@ by the ``tls-authz`` and ``sasl-authz`` options.
>>   The ``pretty=on|off`` switch has no effect for HMP monitors and
>>   its use is rejected.
>>   
>> -``-drive file=json:{...{'driver':'file'}}`` (removed 6.0)
>> +``-drive file=json:{...{'driver':'file'}}`` (removed in 6.0)
> I would not change this in this patch; while the cleanup looks fine,
> there are some more instances and also e.g. things like x.y.z being used
> sometimes, and it's probably better to clean that up via a separated patch.
Yes, I did notice that format (x.y,z) but didn't modify them...
I will make a separate patch only for subject format clean-up and
keep the duplicated text removal in another one.
>>   '''''''''''''''''''''''''''''''''''''''''''''''''''''''''
>>   
>>   The 'file' driver for drives is no longer appropriate for character or host
>> @@ -593,7 +593,7 @@ error when ``-u`` is not used.
>>   Command line options
>>   --------------------
>>   
>> -``-smp`` (invalid topologies) (removed 5.2)
>> +``-smp`` (invalid topologies) (removed in 5.2)
>>   '''''''''''''''''''''''''''''''''''''''''''
>>   
>>   CPU topology properties should describe whole machine topology including
>> @@ -606,7 +606,7 @@ Support for invalid topologies is removed, the user must ensure
>>   topologies described with -smp include all possible cpus, i.e.
>>   *sockets* * *cores* * *threads* = *maxcpus*.
>>   
>> -``-numa`` node (without memory specified) (removed 5.2)
>> +``-numa`` node (without memory specified) (removed in 5.2)
>>   '''''''''''''''''''''''''''''''''''''''''''''''''''''''
>>   
>>   Splitting RAM by default between NUMA nodes had the same issues as ``mem``
>> @@ -647,20 +647,7 @@ as ignored. Currently, users are responsible for making sure the backing storage
>>   specified with ``-mem-path`` can actually provide the guest RAM configured with
>>   ``-m`` and QEMU fails to start up if RAM allocation is unsuccessful.
>>   
>> -``-smp`` (invalid topologies) (removed 5.2)
>> -'''''''''''''''''''''''''''''''''''''''''''
>> -
>> -CPU topology properties should describe whole machine topology including
>> -possible CPUs.
>> -
>> -However, historically it was possible to start QEMU with an incorrect topology
>> -where *n* <= *sockets* * *cores* * *threads* < *maxcpus*,
>> -which could lead to an incorrect topology enumeration by the guest.
>> -Support for invalid topologies is removed, the user must ensure
>> -topologies described with -smp include all possible cpus, i.e.
>> -*sockets* * *cores* * *threads* = *maxcpus*.
> Actually removing the duplicated section looks fine.
Thanks,
Yanan
.
>> -
>> -``-machine enforce-config-section=on|off`` (removed 5.2)
>> +``-machine enforce-config-section=on|off`` (removed in 5.2)
>>   ''''''''''''''''''''''''''''''''''''''''''''''''''''''''
>>   
>>   The ``enforce-config-section`` property was replaced by the
> .

[PATCH, updated 1/2] docs/about/removed-features: Remove duplicated doc about -smp

[Yanan Wang]

There are two places describing the same thing about deprecation
of invalid topologies of -smp CLI, so remove the duplicated one.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
---
 docs/about/removed-features.rst | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
index cbfa1a8e31..6a9c5bb484 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -647,19 +647,6 @@ as ignored. Currently, users are responsible for making sure the backing storage
 specified with ``-mem-path`` can actually provide the guest RAM configured with
 ``-m`` and QEMU fails to start up if RAM allocation is unsuccessful.
 
-``-smp`` (invalid topologies) (removed 5.2)
-'''''''''''''''''''''''''''''''''''''''''''
-
-CPU topology properties should describe whole machine topology including
-possible CPUs.
-
-However, historically it was possible to start QEMU with an incorrect topology
-where *n* <= *sockets* * *cores* * *threads* < *maxcpus*,
-which could lead to an incorrect topology enumeration by the guest.
-Support for invalid topologies is removed, the user must ensure
-topologies described with -smp include all possible cpus, i.e.
-*sockets* * *cores* * *threads* = *maxcpus*.
-
 ``-machine enforce-config-section=on|off`` (removed 5.2)
 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
-- 
2.19.1

Re: [PATCH,updated 1/2] docs/about/removed-features: Remove duplicated doc about -smp

[Cornelia Huck]

On Thu, Aug 19 2021, Yanan Wang <wangyanan55@huawei.com> wrote:

> There are two places describing the same thing about deprecation
> of invalid topologies of -smp CLI, so remove the duplicated one.
>
> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
> ---
>  docs/about/removed-features.rst | 13 -------------
>  1 file changed, 13 deletions(-)

I think we can merge this independently of the main series.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Re: [PATCH,updated 1/2] docs/about/removed-features: Remove duplicated doc about -smp

[wangyanan (Y)]

On 2021/8/19 21:50, Cornelia Huck wrote:
> On Thu, Aug 19 2021, Yanan Wang <wangyanan55@huawei.com> wrote:
>
>> There are two places describing the same thing about deprecation
>> of invalid topologies of -smp CLI, so remove the duplicated one.
>>
>> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
>> ---
>>   docs/about/removed-features.rst | 13 -------------
>>   1 file changed, 13 deletions(-)
> I think we can merge this independently of the main series.
I agree. I can resend these two updated doc clean-up patches separately
with related people on Cc list.
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
>
> .
Thanks,
Yanan

[PATCH,updated 2/2] docs/about: Unify the subject format

[Yanan Wang]

Unify the subject format in deprecated.rst to "since X.Y".
Unify the subject format in removed-features.rst to "removed in X.Y".

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
---
 docs/about/deprecated.rst       | 56 ++++++++++++++++-----------------
 docs/about/removed-features.rst | 28 ++++++++---------
 2 files changed, 42 insertions(+), 42 deletions(-)

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 6d438f1c8d..8d4fd384a5 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -107,8 +107,8 @@ the process listing. This is replaced by the new ``password-secret``
 option which lets the password be securely provided on the command
 line using a ``secret`` object instance.
 
-``opened`` property of ``rng-*`` objects (since 6.0.0)
-''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``opened`` property of ``rng-*`` objects (since 6.0)
+''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 The only effect of specifying ``opened=on`` in the command line or QMP
 ``object-add`` is that the device is opened immediately, possibly before all
@@ -116,8 +116,8 @@ other options have been processed.  This will either have no effect (if
 ``opened`` was the last option) or cause errors.  The property is therefore
 useless and should not be specified.
 
-``loaded`` property of ``secret`` and ``secret_keyring`` objects (since 6.0.0)
-''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``loaded`` property of ``secret`` and ``secret_keyring`` objects (since 6.0)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 The only effect of specifying ``loaded=on`` in the command line or QMP
 ``object-add`` is that the secret is loaded immediately, possibly before all
@@ -142,33 +142,33 @@ should be used instead.
 QEMU Machine Protocol (QMP) commands
 ------------------------------------
 
-``blockdev-open-tray``, ``blockdev-close-tray`` argument ``device`` (since 2.8.0)
-'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``blockdev-open-tray``, ``blockdev-close-tray`` argument ``device`` (since 2.8)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 Use argument ``id`` instead.
 
-``eject`` argument ``device`` (since 2.8.0)
-'''''''''''''''''''''''''''''''''''''''''''
+``eject`` argument ``device`` (since 2.8)
+'''''''''''''''''''''''''''''''''''''''''
 
 Use argument ``id`` instead.
 
-``blockdev-change-medium`` argument ``device`` (since 2.8.0)
-''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``blockdev-change-medium`` argument ``device`` (since 2.8)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 Use argument ``id`` instead.
 
-``block_set_io_throttle`` argument ``device`` (since 2.8.0)
-'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``block_set_io_throttle`` argument ``device`` (since 2.8)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 Use argument ``id`` instead.
 
-``blockdev-add`` empty string argument ``backing`` (since 2.10.0)
-'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``blockdev-add`` empty string argument ``backing`` (since 2.10)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 Use argument value ``null`` instead.
 
-``block-commit`` arguments ``base`` and ``top`` (since 3.1.0)
-'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``block-commit`` arguments ``base`` and ``top`` (since 3.1)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 Use arguments ``base-node`` and ``top-node`` instead.
 
@@ -191,8 +191,8 @@ from Linux upstream kernel, declare it deprecated.
 System emulator CPUS
 --------------------
 
-``Icelake-Client`` CPU Model (since 5.2.0)
-''''''''''''''''''''''''''''''''''''''''''
+``Icelake-Client`` CPU Model (since 5.2)
+''''''''''''''''''''''''''''''''''''''''
 
 ``Icelake-Client`` CPU Models are deprecated. Use ``Icelake-Server`` CPU
 Models instead.
@@ -245,8 +245,8 @@ Device options
 Emulated device options
 '''''''''''''''''''''''
 
-``-device virtio-blk,scsi=on|off`` (since 5.0.0)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+``-device virtio-blk,scsi=on|off`` (since 5.0)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The virtio-blk SCSI passthrough feature is a legacy VIRTIO feature.  VIRTIO 1.0
 and later do not support it because the virtio-scsi device was introduced for
@@ -258,14 +258,14 @@ alias.
 Block device options
 ''''''''''''''''''''
 
-``"backing": ""`` (since 2.12.0)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+``"backing": ""`` (since 2.12)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 In order to prevent QEMU from automatically opening an image's backing
 chain, use ``"backing": null`` instead.
 
-``rbd`` keyvalue pair encoded filenames: ``""`` (since 3.1.0)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+``rbd`` keyvalue pair encoded filenames: ``""`` (since 3.1)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Options for ``rbd`` should be specified according to its runtime options,
 like other block drivers.  Legacy parsing of keyvalue pair encoded
@@ -283,8 +283,8 @@ The above, converted to the current supported format::
 linux-user mode CPUs
 --------------------
 
-``ppc64abi32`` CPUs (since 5.2.0)
-'''''''''''''''''''''''''''''''''
+``ppc64abi32`` CPUs (since 5.2)
+'''''''''''''''''''''''''''''''
 
 The ``ppc64abi32`` architecture has a number of issues which regularly
 trip up our CI testing and is suspected to be quite broken. For that
@@ -303,8 +303,8 @@ Related binaries
 Backwards compatibility
 -----------------------
 
-Runnability guarantee of CPU models (since 4.1.0)
-'''''''''''''''''''''''''''''''''''''''''''''''''
+Runnability guarantee of CPU models (since 4.1)
+'''''''''''''''''''''''''''''''''''''''''''''''
 
 Previous versions of QEMU never changed existing CPU models in
 ways that introduced additional host software or hardware
diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
index 6a9c5bb484..1c926a8bc1 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -194,8 +194,8 @@ by the ``tls-authz`` and ``sasl-authz`` options.
 The ``pretty=on|off`` switch has no effect for HMP monitors and
 its use is rejected.
 
-``-drive file=json:{...{'driver':'file'}}`` (removed 6.0)
-'''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``-drive file=json:{...{'driver':'file'}}`` (removed in 6.0)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 The 'file' driver for drives is no longer appropriate for character or host
 devices and will only accept regular files (S_IFREG). The correct driver
@@ -272,8 +272,8 @@ for the RISC-V ``virt`` machine and ``sifive_u`` machine.
 QEMU Machine Protocol (QMP) commands
 ------------------------------------
 
-``block-dirty-bitmap-add`` "autoload" parameter (removed in 4.2.0)
-''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``block-dirty-bitmap-add`` "autoload" parameter (removed in 4.2)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 The "autoload" parameter has been ignored since 2.12.0. All bitmaps
 are automatically loaded from qcow2 images.
@@ -456,15 +456,15 @@ Nobody was using this CPU emulation in QEMU, and there were no test images
 available to make sure that the code is still working, so it has been removed
 without replacement.
 
-``lm32`` CPUs (removed in 6.1.0)
-''''''''''''''''''''''''''''''''
+``lm32`` CPUs (removed in 6.1)
+''''''''''''''''''''''''''''''
 
 The only public user of this architecture was the milkymist project,
 which has been dead for years; there was never an upstream Linux
 port.  Removed without replacement.
 
-``unicore32`` CPUs (since 6.1.0)
-''''''''''''''''''''''''''''''''
+``unicore32`` CPUs (removed in 6.1)
+'''''''''''''''''''''''''''''''''''
 
 Support for this CPU was removed from the upstream Linux kernel, and
 there is no available upstream toolchain to build binaries for it.
@@ -593,8 +593,8 @@ error when ``-u`` is not used.
 Command line options
 --------------------
 
-``-smp`` (invalid topologies) (removed 5.2)
-'''''''''''''''''''''''''''''''''''''''''''
+``-smp`` (invalid topologies) (removed in 5.2)
+''''''''''''''''''''''''''''''''''''''''''''''
 
 CPU topology properties should describe whole machine topology including
 possible CPUs.
@@ -606,8 +606,8 @@ Support for invalid topologies is removed, the user must ensure
 topologies described with -smp include all possible cpus, i.e.
 *sockets* * *cores* * *threads* = *maxcpus*.
 
-``-numa`` node (without memory specified) (removed 5.2)
-'''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``-numa`` node (without memory specified) (removed in 5.2)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 Splitting RAM by default between NUMA nodes had the same issues as ``mem``
 parameter with the difference that the role of the user plays QEMU using
@@ -647,8 +647,8 @@ as ignored. Currently, users are responsible for making sure the backing storage
 specified with ``-mem-path`` can actually provide the guest RAM configured with
 ``-m`` and QEMU fails to start up if RAM allocation is unsuccessful.
 
-``-machine enforce-config-section=on|off`` (removed 5.2)
-''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+``-machine enforce-config-section=on|off`` (removed in 5.2)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 The ``enforce-config-section`` property was replaced by the
 ``-global migration.send-configuration={on|off}`` option.
-- 
2.19.1

[PATCH v6 02/16] machine: Deprecate "parameter=0" SMP configurations

[Yanan Wang]

In the SMP configuration, we should either provide a topology
parameter with a reasonable value (greater than zero) or just
omit it and QEMU will compute the missing value.

The users shouldn't provide a configuration with any parameter
of it specified as zero (e.g. -smp 8,sockets=0) which could
possibly cause unexpected results in the -smp parsing. So we
deprecate this kind of configurations since 6.2 by adding the
explicit sanity check.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
---
 docs/about/deprecated.rst | 15 +++++++++++++++
 hw/core/machine.c         | 14 ++++++++++++++
 qapi/machine.json         |  2 +-
 qemu-options.hx           | 12 +++++++-----
 4 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 6d438f1c8d..8dbb027dbb 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -138,6 +138,21 @@ an underscore between "window" and "close").
 The ``-no-quit`` is a synonym for ``-display ...,window-close=off`` which
 should be used instead.
 
+``-smp`` ("parameter=0" SMP configurations) (since 6.2)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+Specified CPU topology parameters must be greater than zero.
+
+In the SMP configuration, users should either provide a CPU topology
+parameter with a reasonable value (greater than zero) or just omit it
+and QEMU will compute the missing value.
+
+However, historically it was implicitly allowed for users to provide
+a parameter with zero value, which is meaningless and could also possibly
+cause unexpected results in the -smp parsing. So support for this kind of
+configurations (e.g. -smp 8,sockets=0) is deprecated since 6.2 and will
+be removed in the near future, users have to ensure that all the topology
+members described with -smp are greater than zero.
 
 QEMU Machine Protocol (QMP) commands
 ------------------------------------
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 54e040587d..3b5df9b002 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -832,6 +832,20 @@ static void machine_set_smp(Object *obj, Visitor *v, const char *name,
         return;
     }
 
+    /*
+     * Specified CPU topology parameters must be greater than zero,
+     * 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)) {
+        warn_report("Invalid CPU topology deprecated: "
+                    "CPU topology parameters must be greater than zero");
+    }
+
     mc->smp_parse(ms, config, errp);
     if (*errp) {
         goto out_free;
diff --git a/qapi/machine.json b/qapi/machine.json
index 157712f006..10a97837d3 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -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 83aa59a920..aee622f577 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -227,11 +227,13 @@ 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 greater than zero,
+    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 v6 02/16] machine: Deprecate "parameter=0" SMP configurations

[Cornelia Huck]

On Thu, Aug 19 2021, Yanan Wang <wangyanan55@huawei.com> wrote:

> In the SMP configuration, we should either provide a topology
> parameter with a reasonable value (greater than zero) or just
> omit it and QEMU will compute the missing value.
>
> The users shouldn't provide a configuration with any parameter
> of it specified as zero (e.g. -smp 8,sockets=0) which could
> possibly cause unexpected results in the -smp parsing. So we
> deprecate this kind of configurations since 6.2 by adding the
> explicit sanity check.
>
> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
> ---
>  docs/about/deprecated.rst | 15 +++++++++++++++
>  hw/core/machine.c         | 14 ++++++++++++++
>  qapi/machine.json         |  2 +-
>  qemu-options.hx           | 12 +++++++-----
>  4 files changed, 37 insertions(+), 6 deletions(-)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

[PATCH v6 03/16] machine: Minor refactor/fix for the smp parsers

[Yanan Wang]

To pave the way for the functional improvement in later patches,
make some refactor/cleanup for the smp parsers, including using
local maxcpus instead of ms->smp.max_cpus in the calculation,
defaulting dies to 0 initially like other members, cleanup the
sanity check for dies.

We actually also fix a hidden defect by avoiding directly using
the provided *zero value* in the calculation, which could cause
a segment fault (e.g. using dies=0 in the calculation).

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 hw/core/machine.c | 18 ++++++++++--------
 hw/i386/pc.c      | 23 ++++++++++++++---------
 2 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 3b5df9b002..bcced1e1c4 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -749,8 +749,9 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
     unsigned sockets = config->has_sockets ? config->sockets : 0;
     unsigned cores   = config->has_cores ? config->cores : 0;
     unsigned threads = config->has_threads ? config->threads : 0;
+    unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
 
-    if (config->has_dies && config->dies != 0 && config->dies != 1) {
+    if (config->has_dies && config->dies > 1) {
         error_setg(errp, "dies not supported by this machine's CPU topology");
         return;
     }
@@ -763,8 +764,8 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
             sockets = sockets > 0 ? sockets : 1;
             cpus = cores * threads * sockets;
         } else {
-            ms->smp.max_cpus = config->has_maxcpus ? config->maxcpus : cpus;
-            sockets = ms->smp.max_cpus / (cores * threads);
+            maxcpus = maxcpus > 0 ? maxcpus : cpus;
+            sockets = maxcpus / (cores * threads);
         }
     } else if (cores == 0) {
         threads = threads > 0 ? threads : 1;
@@ -781,26 +782,27 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
         return;
     }
 
-    ms->smp.max_cpus = config->has_maxcpus ? config->maxcpus : cpus;
+    maxcpus = maxcpus > 0 ? maxcpus : cpus;
 
-    if (ms->smp.max_cpus < cpus) {
+    if (maxcpus < cpus) {
         error_setg(errp, "maxcpus must be equal to or greater than smp");
         return;
     }
 
-    if (sockets * cores * threads != ms->smp.max_cpus) {
+    if (sockets * cores * threads != maxcpus) {
         error_setg(errp, "Invalid CPU topology: "
                    "sockets (%u) * cores (%u) * threads (%u) "
                    "!= maxcpus (%u)",
                    sockets, cores, threads,
-                   ms->smp.max_cpus);
+                   maxcpus);
         return;
     }
 
     ms->smp.cpus = cpus;
+    ms->smp.sockets = sockets;
     ms->smp.cores = cores;
     ms->smp.threads = threads;
-    ms->smp.sockets = sockets;
+    ms->smp.max_cpus = maxcpus;
 }
 
 static void machine_get_smp(Object *obj, Visitor *v, const char *name,
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index c2b9d62a35..acd31af452 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -716,9 +716,13 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
 {
     unsigned cpus    = config->has_cpus ? config->cpus : 0;
     unsigned sockets = config->has_sockets ? config->sockets : 0;
-    unsigned dies    = config->has_dies ? config->dies : 1;
+    unsigned dies    = config->has_dies ? config->dies : 0;
     unsigned cores   = config->has_cores ? config->cores : 0;
     unsigned threads = config->has_threads ? config->threads : 0;
+    unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
+
+    /* directly default dies to 1 if it's omitted */
+    dies = dies > 0 ? dies : 1;
 
     /* compute missing values, prefer sockets over cores over threads */
     if (cpus == 0 || sockets == 0) {
@@ -728,8 +732,8 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
             sockets = sockets > 0 ? sockets : 1;
             cpus = cores * threads * dies * sockets;
         } else {
-            ms->smp.max_cpus = config->has_maxcpus ? config->maxcpus : cpus;
-            sockets = ms->smp.max_cpus / (cores * threads * dies);
+            maxcpus = maxcpus > 0 ? maxcpus : cpus;
+            sockets = maxcpus / (dies * cores * threads);
         }
     } else if (cores == 0) {
         threads = threads > 0 ? threads : 1;
@@ -746,27 +750,28 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
         return;
     }
 
-    ms->smp.max_cpus = config->has_maxcpus ? config->maxcpus : cpus;
+    maxcpus = maxcpus > 0 ? maxcpus : cpus;
 
-    if (ms->smp.max_cpus < cpus) {
+    if (maxcpus < cpus) {
         error_setg(errp, "maxcpus must be equal to or greater than smp");
         return;
     }
 
-    if (sockets * dies * cores * threads != ms->smp.max_cpus) {
+    if (sockets * dies * cores * threads != maxcpus) {
         error_setg(errp, "Invalid CPU topology deprecated: "
                    "sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
                    "!= maxcpus (%u)",
                    sockets, dies, cores, threads,
-                   ms->smp.max_cpus);
+                   maxcpus);
         return;
     }
 
     ms->smp.cpus = cpus;
-    ms->smp.cores = cores;
-    ms->smp.threads = threads;
     ms->smp.sockets = sockets;
     ms->smp.dies = dies;
+    ms->smp.cores = cores;
+    ms->smp.threads = threads;
+    ms->smp.maxcpus = maxcpus;
 }
 
 static
-- 
2.19.1

[PATCH v6 04/16] machine: Uniformly use maxcpus to calculate the omitted parameters

[Yanan Wang]

We are currently using maxcpus to calculate the omitted sockets
but using cpus to calculate the omitted cores/threads. This makes
cmdlines like:
  -smp cpus=8,maxcpus=16
  -smp cpus=8,cores=4,maxcpus=16
  -smp cpus=8,threads=2,maxcpus=16
work fine but the ones like:
  -smp cpus=8,sockets=2,maxcpus=16
  -smp cpus=8,sockets=2,cores=4,maxcpus=16
  -smp cpus=8,sockets=2,threads=2,maxcpus=16
break the sanity check.

Since we require for a valid config that the product of "sockets * cores
* threads" should equal to the maxcpus, we should uniformly use maxcpus
to calculate their omitted values.

Also the if-branch of "cpus == 0 || sockets == 0" was split into two
branches of "cpus == 0" and "sockets == 0" so that we can clearly read
that we are parsing the configuration with a preference on cpus over
sockets over cores over threads.

Note: change in this patch won't affect any existing working cmdlines
but improves consistency and allows more incomplete configs to be valid.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
---
 hw/core/machine.c | 30 +++++++++++++++---------------
 hw/i386/pc.c      | 30 +++++++++++++++---------------
 2 files changed, 30 insertions(+), 30 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index bcced1e1c4..dc12b5ec4e 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -757,24 +757,26 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
     }
 
     /* compute missing values, prefer sockets over cores over threads */
-    if (cpus == 0 || sockets == 0) {
+    maxcpus = maxcpus > 0 ? maxcpus : cpus;
+
+    if (cpus == 0) {
+        sockets = sockets > 0 ? sockets : 1;
         cores = cores > 0 ? cores : 1;
         threads = threads > 0 ? threads : 1;
-        if (cpus == 0) {
-            sockets = sockets > 0 ? sockets : 1;
-            cpus = cores * threads * sockets;
-        } else {
-            maxcpus = maxcpus > 0 ? maxcpus : cpus;
-            sockets = maxcpus / (cores * threads);
-        }
+        cpus = sockets * cores * threads;
+        maxcpus = maxcpus > 0 ? maxcpus : cpus;
+    } else if (sockets == 0) {
+        cores = cores > 0 ? cores : 1;
+        threads = threads > 0 ? threads : 1;
+        sockets = maxcpus / (cores * threads);
     } else if (cores == 0) {
         threads = threads > 0 ? threads : 1;
-        cores = cpus / (sockets * threads);
-        cores = cores > 0 ? cores : 1;
+        cores = maxcpus / (sockets * threads);
     } else if (threads == 0) {
-        threads = cpus / (cores * sockets);
-        threads = threads > 0 ? threads : 1;
-    } else if (sockets * cores * threads < cpus) {
+        threads = maxcpus / (sockets * cores);
+    }
+
+    if (sockets * cores * threads < cpus) {
         error_setg(errp, "cpu topology: "
                    "sockets (%u) * cores (%u) * threads (%u) < "
                    "smp_cpus (%u)",
@@ -782,8 +784,6 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
         return;
     }
 
-    maxcpus = maxcpus > 0 ? maxcpus : cpus;
-
     if (maxcpus < cpus) {
         error_setg(errp, "maxcpus must be equal to or greater than smp");
         return;
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index acd31af452..a9ff9ef52c 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -725,24 +725,26 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
     dies = dies > 0 ? dies : 1;
 
     /* compute missing values, prefer sockets over cores over threads */
-    if (cpus == 0 || sockets == 0) {
+    maxcpus = maxcpus > 0 ? maxcpus : cpus;
+
+    if (cpus == 0) {
+        sockets = sockets > 0 ? sockets : 1;
         cores = cores > 0 ? cores : 1;
         threads = threads > 0 ? threads : 1;
-        if (cpus == 0) {
-            sockets = sockets > 0 ? sockets : 1;
-            cpus = cores * threads * dies * sockets;
-        } else {
-            maxcpus = maxcpus > 0 ? maxcpus : cpus;
-            sockets = maxcpus / (dies * cores * threads);
-        }
+        cpus = sockets * dies * cores * threads;
+        maxcpus = maxcpus > 0 ? maxcpus : cpus;
+    } else if (sockets == 0) {
+        cores = cores > 0 ? cores : 1;
+        threads = threads > 0 ? threads : 1;
+        sockets = maxcpus / (dies * cores * threads);
     } else if (cores == 0) {
         threads = threads > 0 ? threads : 1;
-        cores = cpus / (sockets * dies * threads);
-        cores = cores > 0 ? cores : 1;
+        cores = maxcpus / (sockets * dies * threads);
     } else if (threads == 0) {
-        threads = cpus / (cores * dies * sockets);
-        threads = threads > 0 ? threads : 1;
-    } else if (sockets * dies * cores * threads < cpus) {
+        threads = maxcpus / (sockets * dies * cores);
+    }
+
+    if (sockets * dies * cores * threads < cpus) {
         error_setg(errp, "cpu topology: "
                    "sockets (%u) * dies (%u) * cores (%u) * threads (%u) < "
                    "smp_cpus (%u)",
@@ -750,8 +752,6 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
         return;
     }
 
-    maxcpus = maxcpus > 0 ? maxcpus : cpus;
-
     if (maxcpus < cpus) {
         error_setg(errp, "maxcpus must be equal to or greater than smp");
         return;
-- 
2.19.1

[PATCH v6 05/16] machine: Set the value of cpus to match maxcpus if it's omitted

[Yanan Wang]

Currently we directly calculate the omitted cpus based on the given
incomplete collection of parameters. This makes some cmdlines like:
  -smp maxcpus=16
  -smp sockets=2,maxcpus=16
  -smp sockets=2,dies=2,maxcpus=16
  -smp sockets=2,cores=4,maxcpus=16
not work. We should probably set the value of cpus to match maxcpus
if it's omitted, which will make above configs start to work.

So the calculation logic of cpus/maxcpus after this patch will be:
When both maxcpus and cpus are omitted, maxcpus will be calculated
from the given parameters and cpus will be set equal to maxcpus.
When only one of maxcpus and cpus is given then the omitted one
will be set to its counterpart's value. Both maxcpus and cpus may
be specified, but maxcpus must be equal to or greater than cpus.

Note: change in this patch won't affect any existing working cmdlines
but allows more incomplete configs to be valid.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 hw/core/machine.c | 29 ++++++++++++++++-------------
 hw/i386/pc.c      | 29 ++++++++++++++++-------------
 qemu-options.hx   | 11 ++++++++---
 3 files changed, 40 insertions(+), 29 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index dc12b5ec4e..85908abc77 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -757,25 +757,28 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
     }
 
     /* compute missing values, prefer sockets over cores over threads */
-    maxcpus = maxcpus > 0 ? maxcpus : cpus;
-
-    if (cpus == 0) {
+    if (cpus == 0 && maxcpus == 0) {
         sockets = sockets > 0 ? sockets : 1;
         cores = cores > 0 ? cores : 1;
         threads = threads > 0 ? threads : 1;
-        cpus = sockets * cores * threads;
+    } else {
         maxcpus = maxcpus > 0 ? maxcpus : cpus;
-    } else if (sockets == 0) {
-        cores = cores > 0 ? cores : 1;
-        threads = threads > 0 ? threads : 1;
-        sockets = maxcpus / (cores * threads);
-    } else if (cores == 0) {
-        threads = threads > 0 ? threads : 1;
-        cores = maxcpus / (sockets * threads);
-    } else if (threads == 0) {
-        threads = maxcpus / (sockets * cores);
+
+        if (sockets == 0) {
+            cores = cores > 0 ? cores : 1;
+            threads = threads > 0 ? threads : 1;
+            sockets = maxcpus / (cores * threads);
+        } else if (cores == 0) {
+            threads = threads > 0 ? threads : 1;
+            cores = maxcpus / (sockets * threads);
+        } else if (threads == 0) {
+            threads = maxcpus / (sockets * cores);
+        }
     }
 
+    maxcpus = maxcpus > 0 ? maxcpus : sockets * cores * threads;
+    cpus = cpus > 0 ? cpus : maxcpus;
+
     if (sockets * cores * threads < cpus) {
         error_setg(errp, "cpu topology: "
                    "sockets (%u) * cores (%u) * threads (%u) < "
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index a9ff9ef52c..9ad7ae5254 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -725,25 +725,28 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
     dies = dies > 0 ? dies : 1;
 
     /* compute missing values, prefer sockets over cores over threads */
-    maxcpus = maxcpus > 0 ? maxcpus : cpus;
-
-    if (cpus == 0) {
+    if (cpus == 0 && maxcpus == 0) {
         sockets = sockets > 0 ? sockets : 1;
         cores = cores > 0 ? cores : 1;
         threads = threads > 0 ? threads : 1;
-        cpus = sockets * dies * cores * threads;
+    } else {
         maxcpus = maxcpus > 0 ? maxcpus : cpus;
-    } else if (sockets == 0) {
-        cores = cores > 0 ? cores : 1;
-        threads = threads > 0 ? threads : 1;
-        sockets = maxcpus / (dies * cores * threads);
-    } else if (cores == 0) {
-        threads = threads > 0 ? threads : 1;
-        cores = maxcpus / (sockets * dies * threads);
-    } else if (threads == 0) {
-        threads = maxcpus / (sockets * dies * cores);
+
+        if (sockets == 0) {
+            cores = cores > 0 ? cores : 1;
+            threads = threads > 0 ? threads : 1;
+            sockets = maxcpus / (dies * cores * threads);
+        } else if (cores == 0) {
+            threads = threads > 0 ? threads : 1;
+            cores = maxcpus / (sockets * dies * threads);
+        } else if (threads == 0) {
+            threads = maxcpus / (sockets * dies * cores);
+        }
     }
 
+    maxcpus = maxcpus > 0 ? maxcpus : sockets * dies * cores * threads;
+    cpus = cpus > 0 ? cpus : maxcpus;
+
     if (sockets * dies * cores * threads < cpus) {
         error_setg(errp, "cpu topology: "
                    "sockets (%u) * dies (%u) * cores (%u) * threads (%u) < "
diff --git a/qemu-options.hx b/qemu-options.hx
index aee622f577..06f819177e 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -214,9 +214,14 @@ SRST
     Simulate a SMP system with '\ ``n``\ ' CPUs initially present on
     the machine type board. On boards supporting CPU hotplug, the optional
     '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be
-    added at runtime. If omitted the maximum number of CPUs will be
-    set to match the initial CPU count. Both parameters are subject to
-    an upper limit that is determined by the specific machine type chosen.
+    added at runtime. When both parameters are omitted, the maximum number
+    of CPUs will be calculated from the provided topology members and the
+    initial CPU count will match the maximum number. When only one of them
+    is given then the omitted one will be set to its counterpart's value.
+    Both parameters may be specified, but the maximum number of CPUs must
+    be equal to or greater than the initial CPU count. Both parameters are
+    subject to an upper limit that is determined by the specific machine
+    type chosen.
 
     To control reporting of CPU topology information, the number of sockets,
     dies per socket, cores per die, and threads per core can be specified.
-- 
2.19.1

[PATCH v6 06/16] machine: Improve the error reporting of smp parsing

[Yanan Wang]

We have two requirements for a valid SMP configuration:
the product of "sockets * cores * threads" must represent all the
possible cpus, i.e., max_cpus, and then must include the initially
present cpus, i.e., smp_cpus.

So we only need to ensure 1) "sockets * cores * threads == maxcpus"
at first and then ensure 2) "maxcpus >= cpus". With a reasonable
order of the sanity check, we can simplify the error reporting code.
When reporting an error message we also report the exact value of
each topology member to make users easily see what's going on.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
---
 hw/core/machine.c | 22 +++++++++-------------
 hw/i386/pc.c      | 24 ++++++++++--------------
 2 files changed, 19 insertions(+), 27 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 85908abc77..093c0d382d 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -779,25 +779,21 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
     maxcpus = maxcpus > 0 ? maxcpus : sockets * cores * threads;
     cpus = cpus > 0 ? cpus : maxcpus;
 
-    if (sockets * cores * threads < cpus) {
-        error_setg(errp, "cpu topology: "
-                   "sockets (%u) * cores (%u) * threads (%u) < "
-                   "smp_cpus (%u)",
-                   sockets, cores, threads, cpus);
+    if (sockets * cores * threads != maxcpus) {
+        error_setg(errp, "Invalid CPU topology: "
+                   "product of the hierarchy must match maxcpus: "
+                   "sockets (%u) * cores (%u) * threads (%u) "
+                   "!= maxcpus (%u)",
+                   sockets, cores, threads, maxcpus);
         return;
     }
 
     if (maxcpus < cpus) {
-        error_setg(errp, "maxcpus must be equal to or greater than smp");
-        return;
-    }
-
-    if (sockets * cores * threads != maxcpus) {
         error_setg(errp, "Invalid CPU topology: "
+                   "maxcpus must be equal to or greater than smp: "
                    "sockets (%u) * cores (%u) * threads (%u) "
-                   "!= maxcpus (%u)",
-                   sockets, cores, threads,
-                   maxcpus);
+                   "== maxcpus (%u) < smp_cpus (%u)",
+                   sockets, cores, threads, maxcpus, cpus);
         return;
     }
 
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 9ad7ae5254..fcf6905219 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -747,25 +747,21 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
     maxcpus = maxcpus > 0 ? maxcpus : sockets * dies * cores * threads;
     cpus = cpus > 0 ? cpus : maxcpus;
 
-    if (sockets * dies * cores * threads < cpus) {
-        error_setg(errp, "cpu topology: "
-                   "sockets (%u) * dies (%u) * cores (%u) * threads (%u) < "
-                   "smp_cpus (%u)",
-                   sockets, dies, cores, threads, cpus);
+    if (sockets * dies * cores * threads != maxcpus) {
+        error_setg(errp, "Invalid CPU topology: "
+                   "product of the hierarchy must match maxcpus: "
+                   "sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
+                   "!= maxcpus (%u)",
+                   sockets, dies, cores, threads, maxcpus);
         return;
     }
 
     if (maxcpus < cpus) {
-        error_setg(errp, "maxcpus must be equal to or greater than smp");
-        return;
-    }
-
-    if (sockets * dies * cores * threads != maxcpus) {
-        error_setg(errp, "Invalid CPU topology deprecated: "
+        error_setg(errp, "Invalid CPU topology: "
+                   "maxcpus must be equal to or greater than smp: "
                    "sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
-                   "!= maxcpus (%u)",
-                   sockets, dies, cores, threads,
-                   maxcpus);
+                   "== maxcpus (%u) < smp_cpus (%u)",
+                   sockets, dies, cores, threads, maxcpus, cpus);
         return;
     }
 
-- 
2.19.1

[PATCH v6 07/16] hw: Add compat machines for 6.2

[Yanan Wang]

Add 6.2 machine types for arm/i440fx/q35/s390x/spapr.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
---
 hw/arm/virt.c              |  9 ++++++++-
 hw/core/machine.c          |  3 +++
 hw/i386/pc.c               |  3 +++
 hw/i386/pc_piix.c          | 14 +++++++++++++-
 hw/i386/pc_q35.c           | 13 ++++++++++++-
 hw/ppc/spapr.c             | 15 +++++++++++++--
 hw/s390x/s390-virtio-ccw.c | 14 +++++++++++++-
 include/hw/boards.h        |  3 +++
 include/hw/i386/pc.h       |  3 +++
 9 files changed, 71 insertions(+), 6 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 81eda46b0b..01165f7f53 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2788,10 +2788,17 @@ static void machvirt_machine_init(void)
 }
 type_init(machvirt_machine_init);
 
+static void virt_machine_6_2_options(MachineClass *mc)
+{
+}
+DEFINE_VIRT_MACHINE_AS_LATEST(6, 2)
+
 static void virt_machine_6_1_options(MachineClass *mc)
 {
+    virt_machine_6_2_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_6_1, hw_compat_6_1_len);
 }
-DEFINE_VIRT_MACHINE_AS_LATEST(6, 1)
+DEFINE_VIRT_MACHINE(6, 1)
 
 static void virt_machine_6_0_options(MachineClass *mc)
 {
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 093c0d382d..f1b30b3101 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -37,6 +37,9 @@
 #include "hw/virtio/virtio.h"
 #include "hw/virtio/virtio-pci.h"
 
+GlobalProperty hw_compat_6_1[] = {};
+const size_t hw_compat_6_1_len = G_N_ELEMENTS(hw_compat_6_1);
+
 GlobalProperty hw_compat_6_0[] = {
     { "gpex-pcihost", "allow-unmapped-accesses", "false" },
     { "i8042", "extended-state", "false"},
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index fcf6905219..afd8b9c283 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -94,6 +94,9 @@
 #include "trace.h"
 #include CONFIG_DEVICES
 
+GlobalProperty pc_compat_6_1[] = {};
+const size_t pc_compat_6_1_len = G_N_ELEMENTS(pc_compat_6_1);
+
 GlobalProperty pc_compat_6_0[] = {
     { "qemu64" "-" TYPE_X86_CPU, "family", "6" },
     { "qemu64" "-" TYPE_X86_CPU, "model", "6" },
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 30b8bd6ea9..fd5c2277f2 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -413,7 +413,7 @@ static void pc_i440fx_machine_options(MachineClass *m)
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_VMBUS_BRIDGE);
 }
 
-static void pc_i440fx_6_1_machine_options(MachineClass *m)
+static void pc_i440fx_6_2_machine_options(MachineClass *m)
 {
     PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_i440fx_machine_options(m);
@@ -422,6 +422,18 @@ static void pc_i440fx_6_1_machine_options(MachineClass *m)
     pcmc->default_cpu_version = 1;
 }
 
+DEFINE_I440FX_MACHINE(v6_2, "pc-i440fx-6.2", NULL,
+                      pc_i440fx_6_2_machine_options);
+
+static void pc_i440fx_6_1_machine_options(MachineClass *m)
+{
+    pc_i440fx_6_2_machine_options(m);
+    m->alias = NULL;
+    m->is_default = false;
+    compat_props_add(m->compat_props, hw_compat_6_1, hw_compat_6_1_len);
+    compat_props_add(m->compat_props, pc_compat_6_1, pc_compat_6_1_len);
+}
+
 DEFINE_I440FX_MACHINE(v6_1, "pc-i440fx-6.1", NULL,
                       pc_i440fx_6_1_machine_options);
 
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 04b4a4788d..b45903b15e 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -355,7 +355,7 @@ static void pc_q35_machine_options(MachineClass *m)
     m->max_cpus = 288;
 }
 
-static void pc_q35_6_1_machine_options(MachineClass *m)
+static void pc_q35_6_2_machine_options(MachineClass *m)
 {
     PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_q35_machine_options(m);
@@ -363,6 +363,17 @@ static void pc_q35_6_1_machine_options(MachineClass *m)
     pcmc->default_cpu_version = 1;
 }
 
+DEFINE_Q35_MACHINE(v6_2, "pc-q35-6.2", NULL,
+                   pc_q35_6_2_machine_options);
+
+static void pc_q35_6_1_machine_options(MachineClass *m)
+{
+    pc_q35_6_2_machine_options(m);
+    m->alias = NULL;
+    compat_props_add(m->compat_props, hw_compat_6_1, hw_compat_6_1_len);
+    compat_props_add(m->compat_props, pc_compat_6_1, pc_compat_6_1_len);
+}
+
 DEFINE_Q35_MACHINE(v6_1, "pc-q35-6.1", NULL,
                    pc_q35_6_1_machine_options);
 
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 81699d4f8b..d39fd4e644 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4685,15 +4685,26 @@ static void spapr_machine_latest_class_options(MachineClass *mc)
     }                                                                \
     type_init(spapr_machine_register_##suffix)
 
+/*
+ * pseries-6.2
+ */
+static void spapr_machine_6_2_class_options(MachineClass *mc)
+{
+    /* Defaults for the latest behaviour inherited from the base class */
+}
+
+DEFINE_SPAPR_MACHINE(6_2, "6.2", true);
+
 /*
  * pseries-6.1
  */
 static void spapr_machine_6_1_class_options(MachineClass *mc)
 {
-    /* Defaults for the latest behaviour inherited from the base class */
+    spapr_machine_6_2_class_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_6_1, hw_compat_6_1_len);
 }
 
-DEFINE_SPAPR_MACHINE(6_1, "6.1", true);
+DEFINE_SPAPR_MACHINE(6_1, "6.1", false);
 
 /*
  * pseries-6.0
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index e4b18aef49..4d25278cf2 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -791,14 +791,26 @@ bool css_migration_enabled(void)
     }                                                                         \
     type_init(ccw_machine_register_##suffix)
 
+static void ccw_machine_6_2_instance_options(MachineState *machine)
+{
+}
+
+static void ccw_machine_6_2_class_options(MachineClass *mc)
+{
+}
+DEFINE_CCW_MACHINE(6_2, "6.2", true);
+
 static void ccw_machine_6_1_instance_options(MachineState *machine)
 {
+    ccw_machine_6_2_instance_options(machine);
 }
 
 static void ccw_machine_6_1_class_options(MachineClass *mc)
 {
+    ccw_machine_6_2_class_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_6_1, hw_compat_6_1_len);
 }
-DEFINE_CCW_MACHINE(6_1, "6.1", true);
+DEFINE_CCW_MACHINE(6_1, "6.1", false);
 
 static void ccw_machine_6_0_instance_options(MachineState *machine)
 {
diff --git a/include/hw/boards.h b/include/hw/boards.h
index accd6eff35..463a5514f9 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -353,6 +353,9 @@ struct MachineState {
     } \
     type_init(machine_initfn##_register_types)
 
+extern GlobalProperty hw_compat_6_1[];
+extern const size_t hw_compat_6_1_len;
+
 extern GlobalProperty hw_compat_6_0[];
 extern const size_t hw_compat_6_0_len;
 
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 88dffe7517..97b4ab79b5 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -196,6 +196,9 @@ void pc_system_parse_ovmf_flash(uint8_t *flash_ptr, size_t flash_size);
 void pc_madt_cpu_entry(AcpiDeviceIf *adev, int uid,
                        const CPUArchIdList *apic_ids, GArray *entry);
 
+extern GlobalProperty pc_compat_6_1[];
+extern const size_t pc_compat_6_1_len;
+
 extern GlobalProperty pc_compat_6_0[];
 extern const size_t pc_compat_6_0_len;
 
-- 
2.19.1

[PATCH v6 08/16] machine: Prefer cores over sockets in smp parsing since 6.2

[Yanan Wang]

In the real SMP hardware topology world, it's much more likely that
we have high cores-per-socket counts and few sockets totally. While
the current preference of sockets over cores in smp parsing results
in a virtual cpu topology with low cores-per-sockets counts and a
large number of sockets, which is just contrary to the real world.

Given that it is better to make the virtual cpu topology be more
reflective of the real world and also for the sake of compatibility,
we start to prefer cores over sockets over threads in smp parsing
since machine type 6.2 for different arches.

In this patch, a boolean "smp_prefer_sockets" is added, and we only
enable the old preference on older machines and enable the new one
since type 6.2 for all arches by using the machine compat mechanism.

Suggested-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
---
 hw/arm/virt.c              |  1 +
 hw/core/machine.c          | 35 ++++++++++++++++++++++++++---------
 hw/i386/pc.c               | 35 ++++++++++++++++++++++++++---------
 hw/i386/pc_piix.c          |  1 +
 hw/i386/pc_q35.c           |  1 +
 hw/ppc/spapr.c             |  1 +
 hw/s390x/s390-virtio-ccw.c |  1 +
 include/hw/boards.h        |  1 +
 qemu-options.hx            |  3 ++-
 9 files changed, 60 insertions(+), 19 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 01165f7f53..7babea40dc 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2797,6 +2797,7 @@ static void virt_machine_6_1_options(MachineClass *mc)
 {
     virt_machine_6_2_options(mc);
     compat_props_add(mc->compat_props, hw_compat_6_1, hw_compat_6_1_len);
+    mc->smp_prefer_sockets = true;
 }
 DEFINE_VIRT_MACHINE(6, 1)
 
diff --git a/hw/core/machine.c b/hw/core/machine.c
index f1b30b3101..0df597f99c 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -748,6 +748,7 @@ void machine_set_cpu_numa_node(MachineState *machine,
 
 static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
 {
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
     unsigned cpus    = config->has_cpus ? config->cpus : 0;
     unsigned sockets = config->has_sockets ? config->sockets : 0;
     unsigned cores   = config->has_cores ? config->cores : 0;
@@ -759,7 +760,7 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
         return;
     }
 
-    /* compute missing values, prefer sockets over cores over threads */
+    /* compute missing values based on the provided ones */
     if (cpus == 0 && maxcpus == 0) {
         sockets = sockets > 0 ? sockets : 1;
         cores = cores > 0 ? cores : 1;
@@ -767,14 +768,30 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
     } else {
         maxcpus = maxcpus > 0 ? maxcpus : cpus;
 
-        if (sockets == 0) {
-            cores = cores > 0 ? cores : 1;
-            threads = threads > 0 ? threads : 1;
-            sockets = maxcpus / (cores * threads);
-        } else if (cores == 0) {
-            threads = threads > 0 ? threads : 1;
-            cores = maxcpus / (sockets * threads);
-        } else if (threads == 0) {
+        if (mc->smp_prefer_sockets) {
+            /* prefer sockets over cores before 6.2 */
+            if (sockets == 0) {
+                cores = cores > 0 ? cores : 1;
+                threads = threads > 0 ? threads : 1;
+                sockets = maxcpus / (cores * threads);
+            } else if (cores == 0) {
+                threads = threads > 0 ? threads : 1;
+                cores = maxcpus / (sockets * threads);
+            }
+        } else {
+            /* prefer cores over sockets since 6.2 */
+            if (cores == 0) {
+                sockets = sockets > 0 ? sockets : 1;
+                threads = threads > 0 ? threads : 1;
+                cores = maxcpus / (sockets * threads);
+            } else if (sockets == 0) {
+                threads = threads > 0 ? threads : 1;
+                sockets = maxcpus / (cores * threads);
+            }
+        }
+
+        /* try to calculate omitted threads at last */
+        if (threads == 0) {
             threads = maxcpus / (sockets * cores);
         }
     }
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index afd8b9c283..4b05ff7160 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -717,6 +717,7 @@ void pc_acpi_smi_interrupt(void *opaque, int irq, int level)
  */
 static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
 {
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
     unsigned cpus    = config->has_cpus ? config->cpus : 0;
     unsigned sockets = config->has_sockets ? config->sockets : 0;
     unsigned dies    = config->has_dies ? config->dies : 0;
@@ -727,7 +728,7 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
     /* directly default dies to 1 if it's omitted */
     dies = dies > 0 ? dies : 1;
 
-    /* compute missing values, prefer sockets over cores over threads */
+    /* compute missing values based on the provided ones */
     if (cpus == 0 && maxcpus == 0) {
         sockets = sockets > 0 ? sockets : 1;
         cores = cores > 0 ? cores : 1;
@@ -735,14 +736,30 @@ static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **err
     } else {
         maxcpus = maxcpus > 0 ? maxcpus : cpus;
 
-        if (sockets == 0) {
-            cores = cores > 0 ? cores : 1;
-            threads = threads > 0 ? threads : 1;
-            sockets = maxcpus / (dies * cores * threads);
-        } else if (cores == 0) {
-            threads = threads > 0 ? threads : 1;
-            cores = maxcpus / (sockets * dies * threads);
-        } else if (threads == 0) {
+        if (mc->smp_prefer_sockets) {
+            /* prefer sockets over cores before 6.2 */
+            if (sockets == 0) {
+                cores = cores > 0 ? cores : 1;
+                threads = threads > 0 ? threads : 1;
+                sockets = maxcpus / (dies * cores * threads);
+            } else if (cores == 0) {
+                threads = threads > 0 ? threads : 1;
+                cores = maxcpus / (sockets * dies * threads);
+            }
+        } else {
+            /* prefer cores over sockets since 6.2 */
+            if (cores == 0) {
+                sockets = sockets > 0 ? sockets : 1;
+                threads = threads > 0 ? threads : 1;
+                cores = maxcpus / (sockets * dies * threads);
+            } else if (sockets == 0) {
+                threads = threads > 0 ? threads : 1;
+                sockets = maxcpus / (dies * cores * threads);
+            }
+        }
+
+        /* try to calculate omitted threads at last */
+        if (threads == 0) {
             threads = maxcpus / (sockets * dies * cores);
         }
     }
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index fd5c2277f2..9b811fc6ca 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -432,6 +432,7 @@ static void pc_i440fx_6_1_machine_options(MachineClass *m)
     m->is_default = false;
     compat_props_add(m->compat_props, hw_compat_6_1, hw_compat_6_1_len);
     compat_props_add(m->compat_props, pc_compat_6_1, pc_compat_6_1_len);
+    m->smp_prefer_sockets = true;
 }
 
 DEFINE_I440FX_MACHINE(v6_1, "pc-i440fx-6.1", NULL,
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index b45903b15e..88efb7fde4 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -372,6 +372,7 @@ static void pc_q35_6_1_machine_options(MachineClass *m)
     m->alias = NULL;
     compat_props_add(m->compat_props, hw_compat_6_1, hw_compat_6_1_len);
     compat_props_add(m->compat_props, pc_compat_6_1, pc_compat_6_1_len);
+    m->smp_prefer_sockets = true;
 }
 
 DEFINE_Q35_MACHINE(v6_1, "pc-q35-6.1", NULL,
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index d39fd4e644..a481fade51 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4702,6 +4702,7 @@ static void spapr_machine_6_1_class_options(MachineClass *mc)
 {
     spapr_machine_6_2_class_options(mc);
     compat_props_add(mc->compat_props, hw_compat_6_1, hw_compat_6_1_len);
+    mc->smp_prefer_sockets = true;
 }
 
 DEFINE_SPAPR_MACHINE(6_1, "6.1", false);
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 4d25278cf2..b40e647883 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -809,6 +809,7 @@ static void ccw_machine_6_1_class_options(MachineClass *mc)
 {
     ccw_machine_6_2_class_options(mc);
     compat_props_add(mc->compat_props, hw_compat_6_1, hw_compat_6_1_len);
+    mc->smp_prefer_sockets = true;
 }
 DEFINE_CCW_MACHINE(6_1, "6.1", false);
 
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 463a5514f9..2ae039b74f 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -247,6 +247,7 @@ struct MachineClass {
     bool nvdimm_supported;
     bool numa_mem_supported;
     bool auto_enable_numa;
+    bool smp_prefer_sockets;
     const char *default_ram_id;
 
     HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
diff --git a/qemu-options.hx b/qemu-options.hx
index 06f819177e..451d2cd817 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -238,7 +238,8 @@ SRST
     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.
+    liable to change. Prior to 6.2 the preference was sockets over cores
+    over threads. Since 6.2 the preference is cores over sockets over threads.
 ERST
 
 DEF("numa", HAS_ARG, QEMU_OPTION_numa,
-- 
2.19.1

[PATCH v6 09/16] machine: Use ms instead of global current_machine in sanity-check

[Yanan Wang]

In the sanity-check of smp_cpus and max_cpus against mc in function
machine_set_smp(), we are now using ms->smp.max_cpus for the check
but using current_machine->smp.max_cpus in the error message.
Tweak this by uniformly using the local ms.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
---
 hw/core/machine.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 0df597f99c..1ad5dac3e8 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -881,7 +881,7 @@ static void machine_set_smp(Object *obj, Visitor *v, const char *name,
     } else if (ms->smp.max_cpus > mc->max_cpus) {
         error_setg(errp, "Invalid SMP CPUs %d. The max CPUs "
                    "supported by machine '%s' is %d",
-                   current_machine->smp.max_cpus,
+                   ms->smp.max_cpus,
                    mc->name, mc->max_cpus);
     }
 
-- 
2.19.1

[PATCH v6 10/16] machine: Tweak the order of topology members in struct CpuTopology

[Yanan Wang]

Now that all the possible topology parameters are integrated in struct
CpuTopology, tweak the order of topology members to be "cpus/sockets/
dies/cores/threads/maxcpus" for readability and consistency. We also
tweak the comment by adding explanation of dies parameter.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
---
 hw/core/machine.c   | 8 ++++----
 include/hw/boards.h | 7 ++++---
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 1ad5dac3e8..a21fcd7700 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -829,11 +829,11 @@ static void machine_get_smp(Object *obj, Visitor *v, const char *name,
 {
     MachineState *ms = MACHINE(obj);
     SMPConfiguration *config = &(SMPConfiguration){
-        .has_cores = true, .cores = ms->smp.cores,
+        .has_cpus = true, .cpus = ms->smp.cpus,
         .has_sockets = true, .sockets = ms->smp.sockets,
         .has_dies = true, .dies = ms->smp.dies,
+        .has_cores = true, .cores = ms->smp.cores,
         .has_threads = true, .threads = ms->smp.threads,
-        .has_cpus = true, .cpus = ms->smp.cpus,
         .has_maxcpus = true, .maxcpus = ms->smp.max_cpus,
     };
     if (!visit_type_SMPConfiguration(v, name, &config, &error_abort)) {
@@ -1060,10 +1060,10 @@ static void machine_initfn(Object *obj)
     /* default to mc->default_cpus */
     ms->smp.cpus = mc->default_cpus;
     ms->smp.max_cpus = mc->default_cpus;
-    ms->smp.cores = 1;
+    ms->smp.sockets = 1;
     ms->smp.dies = 1;
+    ms->smp.cores = 1;
     ms->smp.threads = 1;
-    ms->smp.sockets = 1;
 }
 
 static void machine_finalize(Object *obj)
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 2ae039b74f..2a1bba86c0 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -275,17 +275,18 @@ typedef struct DeviceMemoryState {
 /**
  * CpuTopology:
  * @cpus: the number of present logical processors on the machine
- * @cores: the number of cores in one package
- * @threads: the number of threads in one core
  * @sockets: the number of sockets on the machine
+ * @dies: the number of dies in one socket
+ * @cores: the number of cores in one die
+ * @threads: the number of threads in one core
  * @max_cpus: the maximum number of logical processors on the machine
  */
 typedef struct CpuTopology {
     unsigned int cpus;
+    unsigned int sockets;
     unsigned int dies;
     unsigned int cores;
     unsigned int threads;
-    unsigned int sockets;
     unsigned int max_cpus;
 } CpuTopology;
 
-- 
2.19.1

[PATCH v6 11/16] machine: Make smp_parse generic enough for all arches

[Yanan Wang]

Currently the only difference between smp_parse and pc_smp_parse
is the support of dies parameter and the related error reporting.
With some arch compat variables like "bool dies_supported", we can
make smp_parse generic enough for all arches and the PC specific
one can be removed.

Making smp_parse() generic enough can reduce code duplication and
ease the code maintenance, and also allows extending the topology
with more arch specific members (e.g., clusters) in the future.

Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 hw/core/machine.c   | 110 ++++++++++++++++++++++++++++++++++++--------
 hw/i386/pc.c        |  84 +--------------------------------
 include/hw/boards.h |   9 ++++
 3 files changed, 100 insertions(+), 103 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index a21fcd7700..4b5c943f8e 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -15,6 +15,7 @@
 #include "qapi/qmp/qerror.h"
 #include "sysemu/replay.h"
 #include "qemu/units.h"
+#include "qemu/cutils.h"
 #include "hw/boards.h"
 #include "hw/loader.h"
 #include "qapi/error.h"
@@ -746,20 +747,87 @@ void machine_set_cpu_numa_node(MachineState *machine,
     }
 }
 
+static char *cpu_topology_hierarchy(MachineState *ms)
+{
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
+    SMPCompatProps *smp_props = &mc->smp_props;
+    char topo_msg[256] = "";
+
+    /*
+     * Topology members should be ordered from the largest to the smallest.
+     * Concept of sockets/cores/threads is supported by default and will be
+     * reported in the hierarchy. Unsupported members will not be reported.
+     */
+    g_autofree char *sockets_msg = g_strdup_printf(
+            " * sockets (%u)", ms->smp.sockets);
+    pstrcat(topo_msg, sizeof(topo_msg), sockets_msg);
+
+    if (smp_props->dies_supported) {
+        g_autofree char *dies_msg = g_strdup_printf(
+                " * dies (%u)", ms->smp.dies);
+        pstrcat(topo_msg, sizeof(topo_msg), dies_msg);
+    }
+
+    g_autofree char *cores_msg = g_strdup_printf(
+            " * cores (%u)", ms->smp.cores);
+    pstrcat(topo_msg, sizeof(topo_msg), cores_msg);
+
+    g_autofree char *threads_msg = g_strdup_printf(
+            " * threads (%u)", ms->smp.threads);
+    pstrcat(topo_msg, sizeof(topo_msg), threads_msg);
+
+    return g_strdup_printf("%s", topo_msg + 3);
+}
+
+/*
+ * smp_parse - Generic function used to parse the given SMP configuration
+ *
+ * If not supported by the machine, a topology parameter must be omitted
+ * or specified equal to 1. Concept of sockets/cores/threads is supported
+ * by default. Unsupported members will not be reported in the topology
+ * hierarchy message.
+ *
+ * For compatibility, omitted arch-specific members (e.g. dies) will not
+ * be computed, but will directly default to 1 instead. This logic should
+ * also apply to future introduced ones.
+ *
+ * Omitted arch-neutral parameters (i.e. cpus/sockets/cores/threads/maxcpus)
+ * will be computed based on the provided ones. When both maxcpus and cpus
+ * are omitted, maxcpus will be computed from the given parameters and cpus
+ * will be set equal to maxcpus. When only one of maxcpus and cpus is given
+ * then the omitted one will be set to its given counterpart's value.
+ * Both maxcpus and cpus may be specified, but maxcpus must be equal to or
+ * greater than cpus.
+ *
+ * In calculation of omitted sockets/cores/threads, we prefer sockets over
+ * cores over threads before 6.2, while preferring cores over sockets over
+ * threads since 6.2.
+ */
 static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
 {
     MachineClass *mc = MACHINE_GET_CLASS(ms);
     unsigned cpus    = config->has_cpus ? config->cpus : 0;
     unsigned sockets = config->has_sockets ? config->sockets : 0;
+    unsigned dies    = config->has_dies ? config->dies : 0;
     unsigned cores   = config->has_cores ? config->cores : 0;
     unsigned threads = config->has_threads ? config->threads : 0;
     unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
 
-    if (config->has_dies && config->dies > 1) {
+    /*
+     * If not supported by the machine, a topology parameter must be
+     * omitted or specified equal to 1.
+     */
+    if (!mc->smp_props.dies_supported && dies > 1) {
         error_setg(errp, "dies not supported by this machine's CPU topology");
         return;
     }
 
+    /*
+     * Omitted arch-specific members will not be computed, but will
+     * directly default to 1 instead.
+     */
+    dies = dies > 0 ? dies : 1;
+
     /* compute missing values based on the provided ones */
     if (cpus == 0 && maxcpus == 0) {
         sockets = sockets > 0 ? sockets : 1;
@@ -773,55 +841,57 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
             if (sockets == 0) {
                 cores = cores > 0 ? cores : 1;
                 threads = threads > 0 ? threads : 1;
-                sockets = maxcpus / (cores * threads);
+                sockets = maxcpus / (dies * cores * threads);
             } else if (cores == 0) {
                 threads = threads > 0 ? threads : 1;
-                cores = maxcpus / (sockets * threads);
+                cores = maxcpus / (sockets * dies * threads);
             }
         } else {
             /* prefer cores over sockets since 6.2 */
             if (cores == 0) {
                 sockets = sockets > 0 ? sockets : 1;
                 threads = threads > 0 ? threads : 1;
-                cores = maxcpus / (sockets * threads);
+                cores = maxcpus / (sockets * dies * threads);
             } else if (sockets == 0) {
                 threads = threads > 0 ? threads : 1;
-                sockets = maxcpus / (cores * threads);
+                sockets = maxcpus / (dies * cores * threads);
             }
         }
 
         /* try to calculate omitted threads at last */
         if (threads == 0) {
-            threads = maxcpus / (sockets * cores);
+            threads = maxcpus / (sockets * dies * cores);
         }
     }
 
-    maxcpus = maxcpus > 0 ? maxcpus : sockets * cores * threads;
+    maxcpus = maxcpus > 0 ? maxcpus : sockets * dies * cores * threads;
     cpus = cpus > 0 ? cpus : maxcpus;
 
-    if (sockets * cores * threads != maxcpus) {
+    ms->smp.cpus = cpus;
+    ms->smp.sockets = sockets;
+    ms->smp.dies = dies;
+    ms->smp.cores = cores;
+    ms->smp.threads = threads;
+    ms->smp.max_cpus = maxcpus;
+
+    /* sanity-check of the computed topology */
+    if (sockets * dies * cores * threads != maxcpus) {
+        g_autofree char *topo_msg = cpu_topology_hierarchy(ms);
         error_setg(errp, "Invalid CPU topology: "
                    "product of the hierarchy must match maxcpus: "
-                   "sockets (%u) * cores (%u) * threads (%u) "
-                   "!= maxcpus (%u)",
-                   sockets, cores, threads, maxcpus);
+                   "%s != maxcpus (%u)",
+                   topo_msg, maxcpus);
         return;
     }
 
     if (maxcpus < cpus) {
+        g_autofree char *topo_msg = cpu_topology_hierarchy(ms);
         error_setg(errp, "Invalid CPU topology: "
                    "maxcpus must be equal to or greater than smp: "
-                   "sockets (%u) * cores (%u) * threads (%u) "
-                   "== maxcpus (%u) < smp_cpus (%u)",
-                   sockets, cores, threads, maxcpus, cpus);
+                   "%s == maxcpus (%u) < smp_cpus (%u)",
+                   topo_msg, maxcpus, cpus);
         return;
     }
-
-    ms->smp.cpus = cpus;
-    ms->smp.sockets = sockets;
-    ms->smp.cores = cores;
-    ms->smp.threads = threads;
-    ms->smp.max_cpus = maxcpus;
 }
 
 static void machine_get_smp(Object *obj, Visitor *v, const char *name,
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 4b05ff7160..ce493a9294 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -711,88 +711,6 @@ void pc_acpi_smi_interrupt(void *opaque, int irq, int level)
     }
 }
 
-/*
- * This function is very similar to smp_parse()
- * in hw/core/machine.c but includes CPU die support.
- */
-static void pc_smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
-{
-    MachineClass *mc = MACHINE_GET_CLASS(ms);
-    unsigned cpus    = config->has_cpus ? config->cpus : 0;
-    unsigned sockets = config->has_sockets ? config->sockets : 0;
-    unsigned dies    = config->has_dies ? config->dies : 0;
-    unsigned cores   = config->has_cores ? config->cores : 0;
-    unsigned threads = config->has_threads ? config->threads : 0;
-    unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
-
-    /* directly default dies to 1 if it's omitted */
-    dies = dies > 0 ? dies : 1;
-
-    /* compute missing values based on the provided ones */
-    if (cpus == 0 && maxcpus == 0) {
-        sockets = sockets > 0 ? sockets : 1;
-        cores = cores > 0 ? cores : 1;
-        threads = threads > 0 ? threads : 1;
-    } else {
-        maxcpus = maxcpus > 0 ? maxcpus : cpus;
-
-        if (mc->smp_prefer_sockets) {
-            /* prefer sockets over cores before 6.2 */
-            if (sockets == 0) {
-                cores = cores > 0 ? cores : 1;
-                threads = threads > 0 ? threads : 1;
-                sockets = maxcpus / (dies * cores * threads);
-            } else if (cores == 0) {
-                threads = threads > 0 ? threads : 1;
-                cores = maxcpus / (sockets * dies * threads);
-            }
-        } else {
-            /* prefer cores over sockets since 6.2 */
-            if (cores == 0) {
-                sockets = sockets > 0 ? sockets : 1;
-                threads = threads > 0 ? threads : 1;
-                cores = maxcpus / (sockets * dies * threads);
-            } else if (sockets == 0) {
-                threads = threads > 0 ? threads : 1;
-                sockets = maxcpus / (dies * cores * threads);
-            }
-        }
-
-        /* try to calculate omitted threads at last */
-        if (threads == 0) {
-            threads = maxcpus / (sockets * dies * cores);
-        }
-    }
-
-    maxcpus = maxcpus > 0 ? maxcpus : sockets * dies * cores * threads;
-    cpus = cpus > 0 ? cpus : maxcpus;
-
-    if (sockets * dies * cores * threads != maxcpus) {
-        error_setg(errp, "Invalid CPU topology: "
-                   "product of the hierarchy must match maxcpus: "
-                   "sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
-                   "!= maxcpus (%u)",
-                   sockets, dies, cores, threads, maxcpus);
-        return;
-    }
-
-    if (maxcpus < cpus) {
-        error_setg(errp, "Invalid CPU topology: "
-                   "maxcpus must be equal to or greater than smp: "
-                   "sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
-                   "== maxcpus (%u) < smp_cpus (%u)",
-                   sockets, dies, cores, threads, maxcpus, cpus);
-        return;
-    }
-
-    ms->smp.cpus = cpus;
-    ms->smp.sockets = sockets;
-    ms->smp.dies = dies;
-    ms->smp.cores = cores;
-    ms->smp.threads = threads;
-    ms->smp.maxcpus = maxcpus;
-}
-
 static
 void pc_machine_done(Notifier *notifier, void *data)
 {
@@ -1746,7 +1664,6 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
     mc->auto_enable_numa_with_memdev = true;
     mc->has_hotpluggable_cpus = true;
     mc->default_boot_order = "cad";
-    mc->smp_parse = pc_smp_parse;
     mc->block_default_type = IF_IDE;
     mc->max_cpus = 255;
     mc->reset = pc_machine_reset;
@@ -1757,6 +1674,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
     hc->unplug = pc_machine_device_unplug_cb;
     mc->default_cpu_type = TARGET_DEFAULT_CPU_TYPE;
     mc->nvdimm_supported = true;
+    mc->smp_props.dies_supported = true;
     mc->default_ram_id = "pc.ram";
 
     object_class_property_add(oc, PC_MACHINE_MAX_RAM_BELOW_4G, "size",
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 2a1bba86c0..72a23e4e0f 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -108,6 +108,14 @@ typedef struct {
     CPUArchId cpus[];
 } CPUArchIdList;
 
+/**
+ * SMPCompatProps:
+ * @dies_supported - whether dies are supported by the machine
+ */
+typedef struct {
+    bool dies_supported;
+} SMPCompatProps;
+
 /**
  * MachineClass:
  * @deprecation_reason: If set, the machine is marked as deprecated. The
@@ -248,6 +256,7 @@ struct MachineClass {
     bool numa_mem_supported;
     bool auto_enable_numa;
     bool smp_prefer_sockets;
+    SMPCompatProps smp_props;
     const char *default_ram_id;
 
     HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
-- 
2.19.1

[PATCH v6 12/16] machine: Remove smp_parse callback from MachineClass

[Yanan Wang]

Now we have a generic smp parser for all arches, and there will
not be any other arch specific ones, so let's remove the callback
from MachineClass and call the parser directly.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 hw/core/machine.c   | 3 +--
 include/hw/boards.h | 5 -----
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 4b5c943f8e..ca7ca68ae3 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -937,7 +937,7 @@ static void machine_set_smp(Object *obj, Visitor *v, const char *name,
                     "CPU topology parameters must be greater than zero");
     }
 
-    mc->smp_parse(ms, config, errp);
+    smp_parse(ms, config, errp);
     if (*errp) {
         goto out_free;
     }
@@ -966,7 +966,6 @@ static void machine_class_init(ObjectClass *oc, void *data)
     /* Default 128 MB as guest ram size */
     mc->default_ram_size = 128 * MiB;
     mc->rom_file_has_mr = true;
-    mc->smp_parse = smp_parse;
 
     /* numa node memory size aligned on 8MB by default.
      * On Linux, each node's border has to be 8MB aligned
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 72a23e4e0f..fa284e01e9 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -177,10 +177,6 @@ typedef struct {
  *    kvm-type may be NULL if it is not needed.
  * @numa_mem_supported:
  *    true if '--numa node.mem' option is supported and false otherwise
- * @smp_parse:
- *    The function pointer to hook different machine specific functions for
- *    parsing "smp-opts" from QemuOpts to MachineState::CpuTopology and more
- *    machine specific topology fields, such as smp_dies for PCMachine.
  * @hotplug_allowed:
  *    If the hook is provided, then it'll be called for each device
  *    hotplug to check whether the device hotplug is allowed.  Return
@@ -217,7 +213,6 @@ struct MachineClass {
     void (*reset)(MachineState *state);
     void (*wakeup)(MachineState *state);
     int (*kvm_type)(MachineState *machine, const char *arg);
-    void (*smp_parse)(MachineState *ms, SMPConfiguration *config, Error **errp);
 
     BlockInterfaceType block_default_type;
     int units_per_default_bus;
-- 
2.19.1

[PATCH v6 13/16] machine: Move smp_prefer_sockets to struct SMPCompatProps

[Yanan Wang]

Now we have a common structure SMPCompatProps used to store information
about SMP compatibility stuff, so we can also move smp_prefer_sockets
there for cleaner code.

No functional change intended.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 hw/arm/virt.c              | 2 +-
 hw/core/machine.c          | 2 +-
 hw/i386/pc_piix.c          | 2 +-
 hw/i386/pc_q35.c           | 2 +-
 hw/ppc/spapr.c             | 2 +-
 hw/s390x/s390-virtio-ccw.c | 2 +-
 include/hw/boards.h        | 3 ++-
 7 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 7babea40dc..ae029680da 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2797,7 +2797,7 @@ static void virt_machine_6_1_options(MachineClass *mc)
 {
     virt_machine_6_2_options(mc);
     compat_props_add(mc->compat_props, hw_compat_6_1, hw_compat_6_1_len);
-    mc->smp_prefer_sockets = true;
+    mc->smp_props.prefer_sockets = true;
 }
 DEFINE_VIRT_MACHINE(6, 1)
 
diff --git a/hw/core/machine.c b/hw/core/machine.c
index ca7ca68ae3..1bdeff32b3 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -836,7 +836,7 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
     } else {
         maxcpus = maxcpus > 0 ? maxcpus : cpus;
 
-        if (mc->smp_prefer_sockets) {
+        if (mc->smp_props.prefer_sockets) {
             /* prefer sockets over cores before 6.2 */
             if (sockets == 0) {
                 cores = cores > 0 ? cores : 1;
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 9b811fc6ca..a60ebfc2c1 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -432,7 +432,7 @@ static void pc_i440fx_6_1_machine_options(MachineClass *m)
     m->is_default = false;
     compat_props_add(m->compat_props, hw_compat_6_1, hw_compat_6_1_len);
     compat_props_add(m->compat_props, pc_compat_6_1, pc_compat_6_1_len);
-    m->smp_prefer_sockets = true;
+    m->smp_props.prefer_sockets = true;
 }
 
 DEFINE_I440FX_MACHINE(v6_1, "pc-i440fx-6.1", NULL,
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 88efb7fde4..4b622ffb82 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -372,7 +372,7 @@ static void pc_q35_6_1_machine_options(MachineClass *m)
     m->alias = NULL;
     compat_props_add(m->compat_props, hw_compat_6_1, hw_compat_6_1_len);
     compat_props_add(m->compat_props, pc_compat_6_1, pc_compat_6_1_len);
-    m->smp_prefer_sockets = true;
+    m->smp_props.prefer_sockets = true;
 }
 
 DEFINE_Q35_MACHINE(v6_1, "pc-q35-6.1", NULL,
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index a481fade51..efdea43c0d 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4702,7 +4702,7 @@ static void spapr_machine_6_1_class_options(MachineClass *mc)
 {
     spapr_machine_6_2_class_options(mc);
     compat_props_add(mc->compat_props, hw_compat_6_1, hw_compat_6_1_len);
-    mc->smp_prefer_sockets = true;
+    mc->smp_props.prefer_sockets = true;
 }
 
 DEFINE_SPAPR_MACHINE(6_1, "6.1", false);
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index b40e647883..5bdef9b4d7 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -809,7 +809,7 @@ static void ccw_machine_6_1_class_options(MachineClass *mc)
 {
     ccw_machine_6_2_class_options(mc);
     compat_props_add(mc->compat_props, hw_compat_6_1, hw_compat_6_1_len);
-    mc->smp_prefer_sockets = true;
+    mc->smp_props.prefer_sockets = true;
 }
 DEFINE_CCW_MACHINE(6_1, "6.1", false);
 
diff --git a/include/hw/boards.h b/include/hw/boards.h
index fa284e01e9..5adbcbb99b 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -110,9 +110,11 @@ typedef struct {
 
 /**
  * SMPCompatProps:
+ * @prefer_sockets - whether sockets are preferred over cores in smp parsing
  * @dies_supported - whether dies are supported by the machine
  */
 typedef struct {
+    bool prefer_sockets;
     bool dies_supported;
 } SMPCompatProps;
 
@@ -250,7 +252,6 @@ struct MachineClass {
     bool nvdimm_supported;
     bool numa_mem_supported;
     bool auto_enable_numa;
-    bool smp_prefer_sockets;
     SMPCompatProps smp_props;
     const char *default_ram_id;
 
-- 
2.19.1

[PATCH v6 14/16] machine: Put all sanity-check in the generic SMP parser

[Yanan Wang]

Put both sanity-check of the input SMP configuration and sanity-check
of the output SMP configuration uniformly in the generic parser. Then
machine_set_smp() will become cleaner, also all the invalid scenarios
can be tested only by calling the parser.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
---
 hw/core/machine.c | 63 +++++++++++++++++++++++------------------------
 1 file changed, 31 insertions(+), 32 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 1bdeff32b3..5b62ba7e34 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -813,6 +813,20 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
     unsigned threads = config->has_threads ? config->threads : 0;
     unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
 
+    /*
+     * Specified CPU topology parameters must be greater than zero,
+     * 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)) {
+        warn_report("Invalid CPU topology deprecated: "
+                    "CPU topology parameters must be greater than zero");
+    }
+
     /*
      * If not supported by the machine, a topology parameter must be
      * omitted or specified equal to 1.
@@ -892,6 +906,22 @@ static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
                    topo_msg, maxcpus, cpus);
         return;
     }
+
+    if (ms->smp.cpus < mc->min_cpus) {
+        error_setg(errp, "Invalid SMP CPUs %d. The min CPUs "
+                   "supported by machine '%s' is %d",
+                   ms->smp.cpus,
+                   mc->name, mc->min_cpus);
+        return;
+    }
+
+    if (ms->smp.max_cpus > mc->max_cpus) {
+        error_setg(errp, "Invalid SMP CPUs %d. The max CPUs "
+                   "supported by machine '%s' is %d",
+                   ms->smp.max_cpus,
+                   mc->name, mc->max_cpus);
+        return;
+    }
 }
 
 static void machine_get_smp(Object *obj, Visitor *v, const char *name,
@@ -914,7 +944,6 @@ static void machine_get_smp(Object *obj, Visitor *v, const char *name,
 static void machine_set_smp(Object *obj, Visitor *v, const char *name,
                             void *opaque, Error **errp)
 {
-    MachineClass *mc = MACHINE_GET_CLASS(obj);
     MachineState *ms = MACHINE(obj);
     SMPConfiguration *config;
     ERRP_GUARD();
@@ -923,40 +952,10 @@ static void machine_set_smp(Object *obj, Visitor *v, const char *name,
         return;
     }
 
-    /*
-     * Specified CPU topology parameters must be greater than zero,
-     * 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)) {
-        warn_report("Invalid CPU topology deprecated: "
-                    "CPU topology parameters must be greater than zero");
-    }
-
     smp_parse(ms, config, errp);
     if (*errp) {
-        goto out_free;
-    }
-
-    /* sanity-check smp_cpus and max_cpus against mc */
-    if (ms->smp.cpus < mc->min_cpus) {
-        error_setg(errp, "Invalid SMP CPUs %d. The min CPUs "
-                   "supported by machine '%s' is %d",
-                   ms->smp.cpus,
-                   mc->name, mc->min_cpus);
-    } else if (ms->smp.max_cpus > mc->max_cpus) {
-        error_setg(errp, "Invalid SMP CPUs %d. The max CPUs "
-                   "supported by machine '%s' is %d",
-                   ms->smp.max_cpus,
-                   mc->name, mc->max_cpus);
+        qapi_free_SMPConfiguration(config);
     }
-
-out_free:
-    qapi_free_SMPConfiguration(config);
 }
 
 static void machine_class_init(ObjectClass *oc, void *data)
-- 
2.19.1

[PATCH v6 15/16] machine: Split out the smp parsing code

[Yanan Wang]

We are going to introduce an unit test for the parser smp_parse()
in hw/core/machine.c, but now machine.c is only built in softmmu.

In order to solve the build dependency on the smp parsing code and
avoid building unrelated stuff for the unit tests, move the related
code from machine.c into a new common file, i.e., machine-smp.c.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 MAINTAINERS           |   1 +
 hw/core/machine-smp.c | 200 ++++++++++++++++++++++++++++++++++++++++++
 hw/core/machine.c     | 178 -------------------------------------
 hw/core/meson.build   |   1 +
 include/hw/boards.h   |   1 +
 5 files changed, 203 insertions(+), 178 deletions(-)
 create mode 100644 hw/core/machine-smp.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 6b3697962c..1e03352501 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1629,6 +1629,7 @@ F: cpu.c
 F: hw/core/cpu.c
 F: hw/core/machine-qmp-cmds.c
 F: hw/core/machine.c
+F: hw/core/machine-smp.c
 F: hw/core/null-machine.c
 F: hw/core/numa.c
 F: hw/cpu/cluster.c
diff --git a/hw/core/machine-smp.c b/hw/core/machine-smp.c
new file mode 100644
index 0000000000..07604aef8d
--- /dev/null
+++ b/hw/core/machine-smp.c
@@ -0,0 +1,200 @@
+/*
+ * QEMU Machine (related to SMP)
+ *
+ * Copyright (c) 2021 Huawei Technologies Co., Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/boards.h"
+#include "qapi/error.h"
+#include "qemu/cutils.h"
+
+static char *cpu_topology_hierarchy(MachineState *ms)
+{
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
+    SMPCompatProps *smp_props = &mc->smp_props;
+    char topo_msg[256] = "";
+
+    /*
+     * Topology members should be ordered from the largest to the smallest.
+     * Concept of sockets/cores/threads is supported by default and will be
+     * reported in the hierarchy. Unsupported members will not be reported.
+     */
+    g_autofree char *sockets_msg = g_strdup_printf(
+            " * sockets (%u)", ms->smp.sockets);
+    pstrcat(topo_msg, sizeof(topo_msg), sockets_msg);
+
+    if (smp_props->dies_supported) {
+        g_autofree char *dies_msg = g_strdup_printf(
+                " * dies (%u)", ms->smp.dies);
+        pstrcat(topo_msg, sizeof(topo_msg), dies_msg);
+    }
+
+    g_autofree char *cores_msg = g_strdup_printf(
+            " * cores (%u)", ms->smp.cores);
+    pstrcat(topo_msg, sizeof(topo_msg), cores_msg);
+
+    g_autofree char *threads_msg = g_strdup_printf(
+            " * threads (%u)", ms->smp.threads);
+    pstrcat(topo_msg, sizeof(topo_msg), threads_msg);
+
+    return g_strdup_printf("%s", topo_msg + 3);
+}
+
+/*
+ * smp_parse - Generic function used to parse the given SMP configuration
+ *
+ * If not supported by the machine, a topology parameter must be omitted
+ * or specified equal to 1. Concept of sockets/cores/threads is supported
+ * by default. Unsupported members will not be reported in the topology
+ * hierarchy message.
+ *
+ * For compatibility, omitted arch-specific members (e.g. dies) will not
+ * be computed, but will directly default to 1 instead. This logic should
+ * also apply to future introduced ones.
+ *
+ * Omitted arch-neutral parameters (i.e. cpus/sockets/cores/threads/maxcpus)
+ * will be computed based on the provided ones. When both maxcpus and cpus
+ * are omitted, maxcpus will be computed from the given parameters and cpus
+ * will be set equal to maxcpus. When only one of maxcpus and cpus is given
+ * then the omitted one will be set to its given counterpart's value.
+ * Both maxcpus and cpus may be specified, but maxcpus must be equal to or
+ * greater than cpus.
+ *
+ * In calculation of omitted sockets/cores/threads, we prefer sockets over
+ * cores over threads before 6.2, while preferring cores over sockets over
+ * threads since 6.2.
+ */
+void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
+{
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
+    unsigned cpus    = config->has_cpus ? config->cpus : 0;
+    unsigned sockets = config->has_sockets ? config->sockets : 0;
+    unsigned dies    = config->has_dies ? config->dies : 0;
+    unsigned cores   = config->has_cores ? config->cores : 0;
+    unsigned threads = config->has_threads ? config->threads : 0;
+    unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
+
+    /*
+     * Specified CPU topology parameters must be greater than zero,
+     * 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)) {
+        warn_report("Invalid CPU topology deprecated: "
+                    "CPU topology parameters must be greater than zero");
+    }
+
+    /*
+     * If not supported by the machine, a topology parameter must be
+     * omitted or specified equal to 1.
+     */
+    if (!mc->smp_props.dies_supported && dies > 1) {
+        error_setg(errp, "dies not supported by this machine's CPU topology");
+        return;
+    }
+
+    /*
+     * Omitted arch-specific members will not be computed, but will
+     * directly default to 1 instead.
+     */
+    dies = dies > 0 ? dies : 1;
+
+    /* compute missing values based on the provided ones */
+    if (cpus == 0 && maxcpus == 0) {
+        sockets = sockets > 0 ? sockets : 1;
+        cores = cores > 0 ? cores : 1;
+        threads = threads > 0 ? threads : 1;
+    } else {
+        maxcpus = maxcpus > 0 ? maxcpus : cpus;
+
+        if (mc->smp_props.prefer_sockets) {
+            /* prefer sockets over cores before 6.2 */
+            if (sockets == 0) {
+                cores = cores > 0 ? cores : 1;
+                threads = threads > 0 ? threads : 1;
+                sockets = maxcpus / (dies * cores * threads);
+            } else if (cores == 0) {
+                threads = threads > 0 ? threads : 1;
+                cores = maxcpus / (sockets * dies * threads);
+            }
+        } else {
+            /* prefer cores over sockets since 6.2 */
+            if (cores == 0) {
+                sockets = sockets > 0 ? sockets : 1;
+                threads = threads > 0 ? threads : 1;
+                cores = maxcpus / (sockets * dies * threads);
+            } else if (sockets == 0) {
+                threads = threads > 0 ? threads : 1;
+                sockets = maxcpus / (dies * cores * threads);
+            }
+        }
+
+        /* try to calculate omitted threads at last */
+        if (threads == 0) {
+            threads = maxcpus / (sockets * dies * cores);
+        }
+    }
+
+    maxcpus = maxcpus > 0 ? maxcpus : sockets * dies * cores * threads;
+    cpus = cpus > 0 ? cpus : maxcpus;
+
+    ms->smp.cpus = cpus;
+    ms->smp.sockets = sockets;
+    ms->smp.dies = dies;
+    ms->smp.cores = cores;
+    ms->smp.threads = threads;
+    ms->smp.max_cpus = maxcpus;
+
+    /* sanity-check of the computed topology */
+    if (sockets * dies * cores * threads != maxcpus) {
+        g_autofree char *topo_msg = cpu_topology_hierarchy(ms);
+        error_setg(errp, "Invalid CPU topology: "
+                   "product of the hierarchy must match maxcpus: "
+                   "%s != maxcpus (%u)",
+                   topo_msg, maxcpus);
+        return;
+    }
+
+    if (maxcpus < cpus) {
+        g_autofree char *topo_msg = cpu_topology_hierarchy(ms);
+        error_setg(errp, "Invalid CPU topology: "
+                   "maxcpus must be equal to or greater than smp: "
+                   "%s == maxcpus (%u) < smp_cpus (%u)",
+                   topo_msg, maxcpus, cpus);
+        return;
+    }
+
+    if (ms->smp.cpus < mc->min_cpus) {
+        error_setg(errp, "Invalid SMP CPUs %d. The min CPUs "
+                   "supported by machine '%s' is %d",
+                   ms->smp.cpus,
+                   mc->name, mc->min_cpus);
+        return;
+    }
+
+    if (ms->smp.max_cpus > mc->max_cpus) {
+        error_setg(errp, "Invalid SMP CPUs %d. The max CPUs "
+                   "supported by machine '%s' is %d",
+                   ms->smp.max_cpus,
+                   mc->name, mc->max_cpus);
+        return;
+    }
+}
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 5b62ba7e34..771c0be17d 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -15,7 +15,6 @@
 #include "qapi/qmp/qerror.h"
 #include "sysemu/replay.h"
 #include "qemu/units.h"
-#include "qemu/cutils.h"
 #include "hw/boards.h"
 #include "hw/loader.h"
 #include "qapi/error.h"
@@ -747,183 +746,6 @@ void machine_set_cpu_numa_node(MachineState *machine,
     }
 }
 
-static char *cpu_topology_hierarchy(MachineState *ms)
-{
-    MachineClass *mc = MACHINE_GET_CLASS(ms);
-    SMPCompatProps *smp_props = &mc->smp_props;
-    char topo_msg[256] = "";
-
-    /*
-     * Topology members should be ordered from the largest to the smallest.
-     * Concept of sockets/cores/threads is supported by default and will be
-     * reported in the hierarchy. Unsupported members will not be reported.
-     */
-    g_autofree char *sockets_msg = g_strdup_printf(
-            " * sockets (%u)", ms->smp.sockets);
-    pstrcat(topo_msg, sizeof(topo_msg), sockets_msg);
-
-    if (smp_props->dies_supported) {
-        g_autofree char *dies_msg = g_strdup_printf(
-                " * dies (%u)", ms->smp.dies);
-        pstrcat(topo_msg, sizeof(topo_msg), dies_msg);
-    }
-
-    g_autofree char *cores_msg = g_strdup_printf(
-            " * cores (%u)", ms->smp.cores);
-    pstrcat(topo_msg, sizeof(topo_msg), cores_msg);
-
-    g_autofree char *threads_msg = g_strdup_printf(
-            " * threads (%u)", ms->smp.threads);
-    pstrcat(topo_msg, sizeof(topo_msg), threads_msg);
-
-    return g_strdup_printf("%s", topo_msg + 3);
-}
-
-/*
- * smp_parse - Generic function used to parse the given SMP configuration
- *
- * If not supported by the machine, a topology parameter must be omitted
- * or specified equal to 1. Concept of sockets/cores/threads is supported
- * by default. Unsupported members will not be reported in the topology
- * hierarchy message.
- *
- * For compatibility, omitted arch-specific members (e.g. dies) will not
- * be computed, but will directly default to 1 instead. This logic should
- * also apply to future introduced ones.
- *
- * Omitted arch-neutral parameters (i.e. cpus/sockets/cores/threads/maxcpus)
- * will be computed based on the provided ones. When both maxcpus and cpus
- * are omitted, maxcpus will be computed from the given parameters and cpus
- * will be set equal to maxcpus. When only one of maxcpus and cpus is given
- * then the omitted one will be set to its given counterpart's value.
- * Both maxcpus and cpus may be specified, but maxcpus must be equal to or
- * greater than cpus.
- *
- * In calculation of omitted sockets/cores/threads, we prefer sockets over
- * cores over threads before 6.2, while preferring cores over sockets over
- * threads since 6.2.
- */
-static void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp)
-{
-    MachineClass *mc = MACHINE_GET_CLASS(ms);
-    unsigned cpus    = config->has_cpus ? config->cpus : 0;
-    unsigned sockets = config->has_sockets ? config->sockets : 0;
-    unsigned dies    = config->has_dies ? config->dies : 0;
-    unsigned cores   = config->has_cores ? config->cores : 0;
-    unsigned threads = config->has_threads ? config->threads : 0;
-    unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
-
-    /*
-     * Specified CPU topology parameters must be greater than zero,
-     * 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)) {
-        warn_report("Invalid CPU topology deprecated: "
-                    "CPU topology parameters must be greater than zero");
-    }
-
-    /*
-     * If not supported by the machine, a topology parameter must be
-     * omitted or specified equal to 1.
-     */
-    if (!mc->smp_props.dies_supported && dies > 1) {
-        error_setg(errp, "dies not supported by this machine's CPU topology");
-        return;
-    }
-
-    /*
-     * Omitted arch-specific members will not be computed, but will
-     * directly default to 1 instead.
-     */
-    dies = dies > 0 ? dies : 1;
-
-    /* compute missing values based on the provided ones */
-    if (cpus == 0 && maxcpus == 0) {
-        sockets = sockets > 0 ? sockets : 1;
-        cores = cores > 0 ? cores : 1;
-        threads = threads > 0 ? threads : 1;
-    } else {
-        maxcpus = maxcpus > 0 ? maxcpus : cpus;
-
-        if (mc->smp_props.prefer_sockets) {
-            /* prefer sockets over cores before 6.2 */
-            if (sockets == 0) {
-                cores = cores > 0 ? cores : 1;
-                threads = threads > 0 ? threads : 1;
-                sockets = maxcpus / (dies * cores * threads);
-            } else if (cores == 0) {
-                threads = threads > 0 ? threads : 1;
-                cores = maxcpus / (sockets * dies * threads);
-            }
-        } else {
-            /* prefer cores over sockets since 6.2 */
-            if (cores == 0) {
-                sockets = sockets > 0 ? sockets : 1;
-                threads = threads > 0 ? threads : 1;
-                cores = maxcpus / (sockets * dies * threads);
-            } else if (sockets == 0) {
-                threads = threads > 0 ? threads : 1;
-                sockets = maxcpus / (dies * cores * threads);
-            }
-        }
-
-        /* try to calculate omitted threads at last */
-        if (threads == 0) {
-            threads = maxcpus / (sockets * dies * cores);
-        }
-    }
-
-    maxcpus = maxcpus > 0 ? maxcpus : sockets * dies * cores * threads;
-    cpus = cpus > 0 ? cpus : maxcpus;
-
-    ms->smp.cpus = cpus;
-    ms->smp.sockets = sockets;
-    ms->smp.dies = dies;
-    ms->smp.cores = cores;
-    ms->smp.threads = threads;
-    ms->smp.max_cpus = maxcpus;
-
-    /* sanity-check of the computed topology */
-    if (sockets * dies * cores * threads != maxcpus) {
-        g_autofree char *topo_msg = cpu_topology_hierarchy(ms);
-        error_setg(errp, "Invalid CPU topology: "
-                   "product of the hierarchy must match maxcpus: "
-                   "%s != maxcpus (%u)",
-                   topo_msg, maxcpus);
-        return;
-    }
-
-    if (maxcpus < cpus) {
-        g_autofree char *topo_msg = cpu_topology_hierarchy(ms);
-        error_setg(errp, "Invalid CPU topology: "
-                   "maxcpus must be equal to or greater than smp: "
-                   "%s == maxcpus (%u) < smp_cpus (%u)",
-                   topo_msg, maxcpus, cpus);
-        return;
-    }
-
-    if (ms->smp.cpus < mc->min_cpus) {
-        error_setg(errp, "Invalid SMP CPUs %d. The min CPUs "
-                   "supported by machine '%s' is %d",
-                   ms->smp.cpus,
-                   mc->name, mc->min_cpus);
-        return;
-    }
-
-    if (ms->smp.max_cpus > mc->max_cpus) {
-        error_setg(errp, "Invalid SMP CPUs %d. The max CPUs "
-                   "supported by machine '%s' is %d",
-                   ms->smp.max_cpus,
-                   mc->name, mc->max_cpus);
-        return;
-    }
-}
-
 static void machine_get_smp(Object *obj, Visitor *v, const char *name,
                             void *opaque, Error **errp)
 {
diff --git a/hw/core/meson.build b/hw/core/meson.build
index 18f44fb7c2..6d727c7742 100644
--- a/hw/core/meson.build
+++ b/hw/core/meson.build
@@ -14,6 +14,7 @@ hwcore_files = files(
 )
 
 common_ss.add(files('cpu-common.c'))
+common_ss.add(files('machine-smp.c'))
 common_ss.add(when: 'CONFIG_FITLOADER', if_true: files('loader-fit.c'))
 common_ss.add(when: 'CONFIG_GENERIC_LOADER', if_true: files('generic-loader.c'))
 common_ss.add(when: ['CONFIG_GUEST_LOADER', fdt], if_true: files('guest-loader.c'))
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 5adbcbb99b..e36fc7d861 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -34,6 +34,7 @@ HotpluggableCPUList *machine_query_hotpluggable_cpus(MachineState *machine);
 void machine_set_cpu_numa_node(MachineState *machine,
                                const CpuInstanceProperties *props,
                                Error **errp);
+void smp_parse(MachineState *ms, SMPConfiguration *config, Error **errp);
 
 /**
  * machine_class_allow_dynamic_sysbus_dev: Add type to list of valid devices
-- 
2.19.1

[PATCH v6 16/16] tests/unit: Add a unit test for smp parsing

[Yanan Wang]

Add a QEMU unit test for the parsing of given SMP configuration.
Since all the parsing logic is in generic function smp_parse(),
this test passes different SMP configurations to the function
and compare the parsing result with what is expected.

In the test, all possible collections of the topology parameters
and the corresponding expected results are listed, including the
valid and invalid ones.

The preference of sockets over cores and the preference of cores
over sockets, and the support of multi-dies are also considered.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 MAINTAINERS                 |   1 +
 tests/unit/meson.build      |   1 +
 tests/unit/test-smp-parse.c | 866 ++++++++++++++++++++++++++++++++++++
 3 files changed, 868 insertions(+)
 create mode 100644 tests/unit/test-smp-parse.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 1e03352501..64255fecd4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1639,6 +1639,7 @@ F: include/hw/boards.h
 F: include/hw/core/cpu.h
 F: include/hw/cpu/cluster.h
 F: include/sysemu/numa.h
+F: tests/unit/test-smp-parse.c
 T: git https://gitlab.com/ehabkost/qemu.git machine-next
 
 Xtensa Machines
diff --git a/tests/unit/meson.build b/tests/unit/meson.build
index 5736d285b2..e208173970 100644
--- a/tests/unit/meson.build
+++ b/tests/unit/meson.build
@@ -45,6 +45,7 @@ tests = {
   'test-uuid': [],
   'ptimer-test': ['ptimer-test-stubs.c', meson.source_root() / 'hw/core/ptimer.c'],
   'test-qapi-util': [],
+  'test-smp-parse': [qom, meson.source_root() / 'hw/core/machine-smp.c'],
 }
 
 if have_system or have_tools
diff --git a/tests/unit/test-smp-parse.c b/tests/unit/test-smp-parse.c
new file mode 100644
index 0000000000..836dfd320f
--- /dev/null
+++ b/tests/unit/test-smp-parse.c
@@ -0,0 +1,866 @@
+/*
+ * SMP parsing unit-tests
+ *
+ * Copyright (c) 2021 Huawei Technologies Co., Ltd
+ *
+ * Authors:
+ *  Yanan Wang <wangyanan55@huawei.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qom/object.h"
+#include "qemu/module.h"
+#include "qapi/error.h"
+
+#include "hw/boards.h"
+
+#define T true
+#define F false
+
+#define MIN_CPUS 1
+#define MAX_CPUS 512
+
+/* define a CPU topology hierarchy of sockets/cores/threads */
+#define SMP_CONFIG_GENERIC(ha, a, hb, b, hc, c, hd, d, he, e) \
+        {                                                     \
+            .has_cpus    = ha, .cpus    = a,                  \
+            .has_sockets = hb, .sockets = b,                  \
+            .has_cores   = hc, .cores   = c,                  \
+            .has_threads = hd, .threads = d,                  \
+            .has_maxcpus = he, .maxcpus = e,                  \
+        }
+
+#define CPU_TOPOLOGY_GENERIC(a, b, c, d, e)                   \
+        {                                                     \
+            .cpus     = a,                                    \
+            .sockets  = b,                                    \
+            .cores    = c,                                    \
+            .threads  = d,                                    \
+            .max_cpus = e,                                    \
+        }
+
+/* define a CPU topology hierarchy of sockets/dies/cores/threads */
+#define SMP_CONFIG_WITH_DIES(ha, a, hb, b, hc, c, hd, d, he, e, hf, f) \
+        {                                                     \
+            .has_cpus    = ha, .cpus    = a,                  \
+            .has_sockets = hb, .sockets = b,                  \
+            .has_dies    = hc, .dies    = c,                  \
+            .has_cores   = hd, .cores   = d,                  \
+            .has_threads = he, .threads = e,                  \
+            .has_maxcpus = hf, .maxcpus = f,                  \
+        }
+
+#define CPU_TOPOLOGY_WITH_DIES(a, b, c, d, e, f)              \
+        {                                                     \
+            .cpus     = a,                                    \
+            .sockets  = b,                                    \
+            .dies     = c,                                    \
+            .cores    = d,                                    \
+            .threads  = e,                                    \
+            .max_cpus = f,                                    \
+        }
+
+/**
+ * SMPTestData:
+ * @config - the given SMP configuration
+ * @expect_prefer_sockets - expected topology result for the valid
+ * configuration, when sockets are preferred over cores in parsing
+ * @expect_prefer_cores - expected topology result for the valid
+ * configuration, when cores are preferred over sockets in parsing
+ * @expect_error - expected error report for the invalid configuration
+ */
+typedef struct SMPTestData {
+    SMPConfiguration config;
+    CpuTopology expect_prefer_sockets;
+    CpuTopology expect_prefer_cores;
+    const char *expect_error;
+} SMPTestData;
+
+/* specific machine type info for testing */
+static const TypeInfo smp_machine_info = {
+    .name = TYPE_MACHINE,
+    .parent = TYPE_OBJECT,
+    .class_size = sizeof(MachineClass),
+    .instance_size = sizeof(MachineState),
+};
+
+/*
+ * all possible valid collections of generic topology parameters
+ * and the corresponding expected outputs are listed.
+ */
+static struct SMPTestData data_generic[] = {
+    {
+        /* config: no configuration provided
+         * expect: cpus=1,sockets=1,cores=1,threads=1,maxcpus=1 */
+        .config = SMP_CONFIG_GENERIC(F, 0, F, 0, F, 0, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(1, 1, 1, 1, 1),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(1, 1, 1, 1, 1),
+    }, {
+        /* config: -smp 8
+         * prefer_sockets: cpus=8,sockets=8,cores=1,threads=1,maxcpus=8
+         * prefer_cores: cpus=8,sockets=1,cores=8,threads=1,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(T, 8, F, 0, F, 0, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 8, 1, 1, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 1, 8, 1, 8),
+    }, {
+        /* config: -smp sockets=2
+         * expect: cpus=2,sockets=2,cores=1,threads=1,maxcpus=2 */
+        .config = SMP_CONFIG_GENERIC(F, 0, T, 2, F, 0, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(2, 2, 1, 1, 2),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(2, 2, 1, 1, 2),
+    }, {
+        /* config: -smp cores=4
+         * expect: cpus=4,sockets=1,cores=4,threads=1,maxcpus=4 */
+        .config = SMP_CONFIG_GENERIC(F, 0, F, 0, T, 4, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(4, 1, 4, 1, 4),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(4, 1, 4, 1, 4),
+    }, {
+        /* config: -smp threads=2
+         * expect: cpus=2,sockets=1,cores=1,threads=2,maxcpus=2 */
+        .config = SMP_CONFIG_GENERIC(F, 0, F, 0, F, 0, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(2, 1, 1, 2, 2),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(2, 1, 1, 2, 2),
+    }, {
+        /* config: -smp maxcpus=16
+         * prefer_sockets: cpus=16,sockets=16,cores=1,threads=1,maxcpus=16
+         * prefer_cores: cpus=16,sockets=1,cores=16,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(F, 0, F, 0, F, 0, F, 0, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(16, 16, 1, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(16, 1, 16, 1, 16),
+    }, {
+        /* config: -smp 8,sockets=2
+         * expect: cpus=8,sockets=2,cores=4,threads=1,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(T, 8, T, 2, F, 0, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+    }, {
+        /* config: -smp 8,cores=4
+         * expect: cpus=8,sockets=2,cores=4,threads=1,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(T, 8, F, 0, T, 4, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+    }, {
+        /* config: -smp 8,threads=2
+         * prefer_sockets: cpus=8,sockets=4,cores=1,threads=2,maxcpus=8
+         * prefer_cores: cpus=8,sockets=1,cores=4,threads=2,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(T, 8, F, 0, F, 0, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 4, 1, 2, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 1, 4, 2, 8),
+    }, {
+        /* config: -smp 8,maxcpus=16
+         * prefer_sockets: cpus=8,sockets=16,cores=1,threads=1,maxcpus=16
+         * prefer_cores: cpus=8,sockets=1,cores=16,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(T, 8, F, 0, F, 0, F, 0, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 16, 1, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 1, 16, 1, 16),
+    }, {
+        /* config: -smp sockets=2,cores=4
+         * expect: cpus=8,sockets=2,cores=4,threads=1,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(F, 0, T, 2, T, 4, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+    }, {
+        /* config: -smp sockets=2,threads=2
+         * expect: cpus=4,sockets=2,cores=1,threads=2,maxcpus=4 */
+        .config = SMP_CONFIG_GENERIC(F, 0, T, 2, F, 0, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(4, 2, 1, 2, 4),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(4, 2, 1, 2, 4),
+    }, {
+        /* config: -smp sockets=2,maxcpus=16
+         * expect: cpus=16,sockets=2,cores=8,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(F, 0, T, 2, F, 0, F, 0, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(16, 2, 8, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(16, 2, 8, 1, 16),
+    }, {
+        /* config: -smp cores=4,threads=2
+         * expect: cpus=8,sockets=1,cores=4,threads=2,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(F, 0, F, 0, T, 4, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 1, 4, 2, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 1, 4, 2, 8),
+    }, {
+        /* config: -smp cores=4,maxcpus=16
+         * expect: cpus=16,sockets=4,cores=4,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(F, 0, F, 0, T, 4, F, 0, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(16, 4, 4, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(16, 4, 4, 1, 16),
+    }, {
+        /* config: -smp threads=2,maxcpus=16
+         * prefer_sockets: cpus=16,sockets=8,cores=1,threads=2,maxcpus=16
+         * prefer_cores: cpus=16,sockets=1,cores=8,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(F, 0, F, 0, F, 0, T, 2, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(16, 8, 1, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(16, 1, 8, 2, 16),
+    }, {
+        /* config: -smp 8,sockets=2,cores=4
+         * expect: cpus=8,sockets=2,cores=4,threads=1,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(T, 8, T, 2, T, 4, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+    }, {
+        /* config: -smp 8,sockets=2,threads=2
+         * expect: cpus=8,sockets=2,cores=2,threads=2,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(T, 8, T, 2, F, 0, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 2, 2, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 2, 2, 8),
+    }, {
+        /* config: -smp 8,sockets=2,maxcpus=16
+         * expect: cpus=8,sockets=2,cores=8,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(T, 8, T, 2, F, 0, F, 0, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 8, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 8, 1, 16),
+    }, {
+        /* config: -smp 8,cores=4,threads=2
+         * expect: cpus=8,sockets=1,cores=4,threads=2,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(T, 8, F, 0, T, 4, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 1, 4, 2, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 1, 4, 2, 8),
+    }, {
+        /* config: -smp 8,cores=4,maxcpus=16
+         * expect: cpus=8,sockets=4,cores=4,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(T, 8, F, 0, T, 4, F, 0, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 4, 4, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 4, 4, 1, 16),
+    }, {
+        /* config: -smp 8,threads=2,maxcpus=16
+         * prefer_sockets: cpus=8,sockets=8,cores=1,threads=2,maxcpus=16
+         * prefer_cores: cpus=8,sockets=1,cores=8,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(T, 8, F, 0, F, 0, T, 2, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 8, 1, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 1, 8, 2, 16),
+    }, {
+        /* config: -smp sockets=2,cores=4,threads=2
+         * expect: cpus=16,sockets=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(F, 0, T, 2, T, 4, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+    }, {
+        /* config: -smp sockets=2,cores=4,maxcpus=16
+         * expect: cpus=16,sockets=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(F, 0, T, 2, T, 4, F, 0, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+    }, {
+        /* config: -smp sockets=2,threads=2,maxcpus=16
+         * expect: cpus=16,sockets=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(F, 0, T, 2, F, 0, T, 2, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+    }, {
+        /* config: -smp cores=4,threads=2,maxcpus=16
+         * expect: cpus=16,sockets=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(F, 0, F, 0, T, 4, T, 2, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+    }, {
+        /* config: -smp 8,sockets=2,cores=4,threads=1
+         * expect: cpus=8,sockets=2,cores=4,threads=1,maxcpus=8 */
+        .config = SMP_CONFIG_GENERIC(T, 8, T, 2, T, 4, T, 1, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 4, 1, 8),
+    }, {
+        /* config: -smp 8,sockets=2,cores=4,maxcpus=16
+         * expect: cpus=8,sockets=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(T, 8, T, 2, T, 4, F, 0, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 4, 2, 16),
+    }, {
+        /* config: -smp 8,sockets=2,threads=2,maxcpus=16
+         * expect: cpus=8,sockets=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(T, 8, T, 2, F, 0, T, 2, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 4, 2, 16),
+    }, {
+        /* config: -smp 8,cores=4,threads=2,maxcpus=16
+         * expect: cpus=8,sockets=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(T, 8, F, 0, T, 4, T, 2, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 4, 2, 16),
+    }, {
+        /* config: -smp sockets=2,cores=4,threads=2,maxcpus=16
+         * expect: cpus=16,sockets=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(F, 0, T, 2, T, 4, T, 2, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(16, 2, 4, 2, 16),
+    }, {
+        /* config: -smp 8,sockets=2,cores=4,threads=2,maxcpus=16
+         * expect: cpus=8,sockets=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_GENERIC(T, 8, T, 2, T, 4, T, 2, T, 16),
+        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(8, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(8, 2, 4, 2, 16),
+    },
+};
+
+/*
+ * all possible valid collections of topology parameters (with dies)
+ * and the corresponding expected outputs are listed.
+ */
+static SMPTestData data_with_dies[] = {
+    {
+        /* config: -smp dies=2
+         * expect: cpus=2,sockets=1,dies=2,cores=1,threads=1,maxcpus=2 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, F, 0, T, 2, F, 0, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(2, 1, 2, 1, 1, 2),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(2, 1, 2, 1, 1, 2),
+    }, {
+        /* config: -smp 16,dies=2
+         * prefer_sockets: cpus=16,sockets=8,dies=2,cores=1,threads=1,maxcpus=16
+         * prefer_cores: cpus=16,sockets=1,dies=2,cores=8,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, F, 0, T, 2, F, 0, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 8, 2, 1, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 1, 2, 8, 1, 16),
+    }, {
+        /* config: -smp sockets=2,dies=2
+         * expect: cpus=4,sockets=2,dies=2,cores=1,threads=1,maxcpus=4 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, T, 2, T, 2, F, 0, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(4, 2, 2, 1, 1, 4),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(4, 2, 2, 1, 1, 4),
+    }, {
+        /* config: -smp dies=2,cores=4
+         * expect: cpus=8,sockets=1,dies=2,cores=4,threads=1,maxcpus=8 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, F, 0, T, 2, T, 4, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(8, 1, 2, 4, 1, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(8, 1, 2, 4, 1, 8),
+    }, {
+        /* config: -smp dies=2,threads=2
+         * expect: cpus=4,sockets=1,dies=2,cores=1,threads=2,maxcpus=4 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, F, 0, T, 2, F, 0, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(4, 1, 2, 1, 2, 4),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(4, 1, 2, 1, 2, 4),
+    }, {
+        /* config: -smp dies=2,maxcpus=32
+         * prefer_sockets: cpus=32,sockets=16,dies=2,cores=1,threads=1,maxcpus=32
+         * prefer_cores: cpus=32,sockets=1,dies=2,cores=16,threads=1,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, F, 0, T, 2, F, 0, F, 0, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(32, 16, 2, 1, 1, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(32, 1, 2, 16, 1, 32),
+    }, {
+        /* config: -smp 16,sockets=2,dies=2
+         * expect: cpus=16,sockets=2,dies=2,cores=4,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, T, 2, T, 2, F, 0, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+    }, {
+        /* config: -smp 16,dies=2,cores=4
+         * expect: cpus=16,sockets=2,dies=2,cores=4,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, F, 0, T, 2, T, 4, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+    }, {
+        /* config: -smp 16,dies=2,threads=2
+         * prefer_sockets: cpus=16,sockets=4,dies=2,cores=1,threads=2,maxcpus=16
+         * prefer_cores: cpus=16,sockets=1,dies=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, F, 0, T, 2, F, 0, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 4, 2, 1, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 1, 2, 4, 2, 16),
+    }, {
+        /* config: -smp 16,dies=2,maxcpus=32
+         * prefer_sockets: cpus=16,sockets=16,dies=2,cores=1,threads=1,maxcpus=32
+         * prefer_cores: cpus=16,sockets=1,dies=2,cores=16,threads=1,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, F, 0, T, 2, F, 0, F, 0, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 16, 2, 1, 1, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 1, 2, 16, 1, 32),
+    }, {
+        /* config: -smp sockets=2,dies=2,cores=4
+         * expect: cpus=16,sockets=2,dies=2,cores=4,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, T, 2, T, 2, T, 4, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+    }, {
+        /* config: -smp sockets=2,dies=2,threads=2
+         * expect: cpus=8,sockets=2,dies=2,cores=1,threads=2,maxcpus=8 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, T, 2, T, 2, F, 0, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(8, 2, 2, 1, 2, 8),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(8, 2, 2, 1, 2, 8),
+    }, {
+        /* config: -smp sockets=2,dies=2,maxcpus=32
+         * expect: cpus=32,sockets=2,dies=2,cores=8,threads=1,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, T, 2, T, 2, F, 0, F, 0, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 8, 1, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 8, 1, 32),
+    }, {
+        /* config: -smp dies=2,cores=4,threads=2
+         * expect: cpus=16,sockets=1,dies=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, F, 0, T, 2, T, 4, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 1, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 1, 2, 4, 2, 16),
+    }, {
+        /* config: -smp dies=2,cores=4,maxcpus=32
+         * expect: cpus=32,sockets=4,dies=2,cores=4,threads=1,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, F, 0, T, 2, T, 4, F, 0, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(32, 4, 2, 4, 1, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(32, 4, 2, 4, 1, 32),
+    }, {
+        /* config: -smp dies=2,threads=2,maxcpus=32
+         * prefer_sockets: cpus=32,sockets=8,dies=2,cores=1,threads=2,maxcpus=32
+         * prefer_cores: cpus=32,sockets=1,dies=2,cores=8,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, F, 0, T, 2, F, 0, T, 2, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(32, 8, 2, 1, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(32, 1, 2, 8, 2, 32),
+    }, {
+        /* config: -smp 16,sockets=2,dies=2,cores=4
+         * expect: cpus=16,sockets=2,dies=2,cores=4,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, T, 2, T, 2, T, 4, F, 0, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+    }, {
+        /* config: -smp 16,sockets=2,dies=2,threads=2
+         * expect: cpus=16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, T, 2, T, 2, F, 0, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 2, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 2, 2, 16),
+    }, {
+        /* config: -smp 16,sockets=2,dies=2,maxcpus=32
+         * expect: cpus=16,sockets=2,dies=2,cores=8,threads=1,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, T, 2, T, 2, F, 0, F, 0, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 8, 1, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 8, 1, 32),
+    }, {
+        /* config: -smp 16,dies=2,cores=4,threads=2
+         * expect: cpus=16,sockets=1,dies=2,cores=4,threads=2,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, F, 0, T, 2, T, 4, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 1, 2, 4, 2, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 1, 2, 4, 2, 16),
+    }, {
+        /* config: -smp 16,dies=2,cores=4,maxcpus=32
+         * expect: cpus=16,sockets=4,dies=2,cores=4,threads=1,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, F, 0, T, 2, T, 4, F, 0, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 4, 2, 4, 1, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 4, 2, 4, 1, 32),
+    }, {
+        /* config: -smp 16,dies=2,threads=2,maxcpus=32
+         * prefer_sockets: cpus=16,sockets=8,dies=2,cores=1,threads=2,maxcpus=32
+         * prefer_cores: cpus=16,sockets=1,dies=2,cores=8,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, F, 0, T, 2, F, 0, T, 2, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 8, 2, 1, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 1, 2, 8, 2, 32),
+    }, {
+        /* config: -smp sockets=2,dies=2,cores=4,threads=2
+         * expect: cpus=32,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, T, 2, T, 2, T, 4, T, 2, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+    }, {
+        /* config: -smp sockets=2,dies=2,cores=4,maxcpus=32
+         * expect: cpus=32,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, T, 2, T, 2, T, 4, F, 0, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+    }, {
+        /* config: -smp sockets=2,dies=2,threads=2,maxcpus=32
+         * expect: cpus=32,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, T, 2, T, 2, F, 0, T, 2, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+    }, {
+        /* config: -smp dies=2,cores=4,threads=2,maxcpus=32
+         * expect: cpus=32,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, F, 0, T, 2, T, 4, T, 2, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+    }, {
+        /* config: -smp 16,sockets=2,dies=2,cores=4,threads=1
+         * expect: cpus=16,sockets=2,dies=2,cores=4,threads=1,maxcpus=16 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, T, 2, T, 2, T, 4, T, 1, F, 0),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 1, 16),
+    }, {
+        /* config: -smp 16,sockets=2,dies=2,cores=4,maxcpus=32
+         * expect: cpus=16,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, T, 2, T, 2, T, 4, F, 0, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 2, 32),
+    }, {
+        /* config: -smp 16,sockets=2,dies=2,threads=2,maxcpus=32
+         * expect: cpus=16,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, T, 2, T, 2, F, 0, T, 2, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 2, 32),
+    }, {
+        /* config: -smp 16,dies=2,cores=4,threads=2,maxcpus=32
+         * expect: cpus=16,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, F, 0, T, 2, T, 4, T, 2, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 2, 32),
+    }, {
+        /* config: -smp sockets=2,dies=2,cores=4,threads=2,maxcpus=32
+         * expect: cpus=32,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(F, 0, T, 2, T, 2, T, 4, T, 2, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(32, 2, 2, 4, 2, 32),
+    }, {
+        /* config: -smp 16,sockets=2,dies=2,cores=4,threads=2,maxcpus=32
+         * expect: cpus=16,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+        .config = SMP_CONFIG_WITH_DIES(T, 16, T, 2, T, 2, T, 4, T, 2, T, 32),
+        .expect_prefer_sockets = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 2, 32),
+        .expect_prefer_cores   = CPU_TOPOLOGY_WITH_DIES(16, 2, 2, 4, 2, 32),
+    },
+};
+
+/*
+ * generic invalid configurations
+ * specified smp CPUs can't be less than supported min CPUs.
+ * specified max CPUs can't be more than supported max CPUs.
+ */
+
+static SMPTestData data_generic_invalid[] = {
+    {
+        /* config: -smp MIN_CPUS
+         * reset the machine supported min CPUs to "MIN_CPUS + 1" */
+        .config = SMP_CONFIG_GENERIC(T, MIN_CPUS, F, 0, F, 0, F, 0, F, 0),
+        .expect_error = "Invalid SMP CPUs 1. The min CPUs supported "
+                        "by machine '(null)' is 2",
+    }, {
+        /* config: -smp MAX_CPUS
+         * reset the machine supported max CPUs to "MAX_CPUS - 1" */
+        .config = SMP_CONFIG_GENERIC(T, MAX_CPUS, F, 0, F, 0, F, 0, F, 0),
+        .expect_error = "Invalid SMP CPUs 512. The max CPUs supported "
+                        "by machine '(null)' is 511",
+    },
+};
+
+static char *get_config_info(SMPConfiguration *config)
+{
+    return g_strdup_printf(
+        "(SMPConfiguration) {\n"
+        "    .has_cpus    = %5s, cpus    = %ld,\n"
+        "    .has_sockets = %5s, sockets = %ld,\n"
+        "    .has_dies    = %5s, dies    = %ld,\n"
+        "    .has_cores   = %5s, cores   = %ld,\n"
+        "    .has_threads = %5s, threads = %ld,\n"
+        "    .has_maxcpus = %5s, maxcpus = %ld,\n"
+        "}",
+        config->has_cpus ? "true" : "false", config->cpus,
+        config->has_sockets ? "true" : "false", config->sockets,
+        config->has_dies ? "true" : "false", config->dies,
+        config->has_cores ? "true" : "false", config->cores,
+        config->has_threads ? "true" : "false", config->threads,
+        config->has_maxcpus ? "true" : "false", config->maxcpus);
+}
+
+static char *get_topo_info(CpuTopology *topo)
+{
+    return g_strdup_printf(
+        "(CpuTopology) {\n"
+        "    .cpus     = %u,\n"
+        "    .sockets  = %u,\n"
+        "    .dies     = %u,\n"
+        "    .cores    = %u,\n"
+        "    .threads  = %u,\n"
+        "    .max_cpus = %u,\n"
+        "}",
+        topo->cpus, topo->sockets, topo->dies,
+        topo->cores, topo->threads, topo->max_cpus);
+}
+
+static void check_smp_parse(MachineState *ms, SMPConfiguration *config,
+                            CpuTopology *expect_topo, const char *expect_err,
+                            bool valid)
+{
+    g_autofree char *config_info = NULL;
+    g_autofree char *expect_topo_info = NULL;
+    g_autofree char *result_topo_info = NULL;
+    const char *result_err;
+    Error *err = NULL;
+
+    /* call the generic parser smp_parse() in hw/core/machine-smp.c */
+    smp_parse(ms, config, &err);
+
+    if (valid) {
+        if ((err == NULL) &&
+            (ms->smp.cpus == expect_topo->cpus) &&
+            (ms->smp.sockets == expect_topo->sockets) &&
+            (ms->smp.dies == expect_topo->dies) &&
+            (ms->smp.cores == expect_topo->cores) &&
+            (ms->smp.threads == expect_topo->threads) &&
+            (ms->smp.max_cpus == expect_topo->max_cpus)) {
+            return;
+        }
+
+        config_info = get_config_info(config);
+        expect_topo_info = get_topo_info(expect_topo);
+
+        if (err != NULL) {
+            g_printerr("Check smp_parse failed:\n"
+                       "config: %s\n"
+                       "expect_topo: %s\n"
+                       "should_be_valid: yes\n\n"
+                       "result_is_valid: no\n"
+                       "result_error: %s\n",
+                       config_info, expect_topo_info,
+                       error_get_pretty(err));
+            error_free(err);
+        } else {
+            result_topo_info = get_topo_info(&ms->smp);
+            g_printerr("Check smp_parse failed:\n"
+                       "config: %s\n"
+                       "expect_topo: %s\n"
+                       "should_be_valid: yes\n\n"
+                       "result_is_valid: yes\n"
+                       "result_topo: %s\n",
+                       config_info, expect_topo_info,
+                       result_topo_info);
+        }
+    } else {
+        if (err != NULL) {
+            result_err = error_get_pretty(err);
+
+            if (expect_err == NULL || (expect_err != NULL &&
+                g_str_equal(expect_err, result_err))) {
+                error_free(err);
+                return;
+            }
+
+            config_info = get_config_info(config);
+            g_printerr("Check smp_parse failed:\n"
+                       "config: %s\n"
+                       "expect_error: %s\n"
+                       "should_be_valid: no\n\n"
+                       "result_is_valid: no\n"
+                       "result_error: %s\n",
+                       config_info, expect_err, result_err);
+            error_free(err);
+        } else {
+            config_info = get_config_info(config);
+            result_topo_info = get_topo_info(&ms->smp);
+
+            g_printerr("Check smp_parse failed:\n"
+                       "config: %s\n"
+                       "should_be_valid: no\n\n"
+                       "result_is_valid: yes\n"
+                       "result_topo: %s\n",
+                       config_info, result_topo_info);
+        }
+    }
+
+    abort();
+}
+
+static void smp_test_data_init(SMPTestData *targ, SMPTestData *src)
+{
+    targ->config = src->config;
+    targ->expect_prefer_sockets = src->expect_prefer_sockets;
+    targ->expect_prefer_cores = src->expect_prefer_cores;
+    targ->expect_error = src->expect_error;
+}
+
+static void smp_machine_class_reinit(MachineClass *mc)
+{
+    mc->min_cpus = MIN_CPUS;
+    mc->max_cpus = MAX_CPUS;
+
+    mc->smp_props.prefer_sockets = true;
+    mc->smp_props.dies_supported = false;
+}
+
+static void smp_generic_test(void)
+{
+    Object *obj = object_new(TYPE_MACHINE);
+    MachineState *ms = MACHINE(obj);
+    MachineClass *mc = MACHINE_GET_CLASS(obj);
+    SMPTestData data;
+    int i;
+
+    /* make sure that we have created the object */
+    g_assert_nonnull(ms);
+    g_assert_nonnull(mc);
+
+    /* reinitialize related machine properties before each subtest */
+    smp_machine_class_reinit(mc);
+
+    for (i = 0; i < ARRAY_SIZE(data_generic); i++) {
+        smp_test_data_init(&data, &data_generic[i]);
+
+        /* parsed values of unsupported parameters should be 1 */
+        data.expect_prefer_sockets.dies = 1;
+        data.expect_prefer_cores.dies = 1;
+
+        mc->smp_props.prefer_sockets = true;
+        check_smp_parse(ms, &data.config,
+                        &data.expect_prefer_sockets, NULL, true);
+
+        mc->smp_props.prefer_sockets = false;
+        check_smp_parse(ms, &data.config,
+                        &data.expect_prefer_cores, NULL, true);
+
+        /*
+         * it's now allowed that unsupported dies can be set equal to 1
+         * in the SMP configuration.
+         */
+        data.config.has_dies = true;
+        data.config.dies = 1;
+
+        mc->smp_props.prefer_sockets = true;
+        check_smp_parse(ms, &data.config,
+                        &data.expect_prefer_sockets, NULL, true);
+
+        mc->smp_props.prefer_sockets = false;
+        check_smp_parse(ms, &data.config,
+                        &data.expect_prefer_cores, NULL, true);
+    }
+
+    object_unref(obj);
+}
+
+static void smp_with_dies_test(void)
+{
+    Object *obj = object_new(TYPE_MACHINE);
+    MachineState *ms = MACHINE(obj);
+    MachineClass *mc = MACHINE_GET_CLASS(obj);
+    SMPTestData data;
+    int i;
+
+    /* make sure that we have created the object */
+    g_assert_nonnull(ms);
+    g_assert_nonnull(mc);
+
+    /* reinitialize related machine properties before each subtest */
+    smp_machine_class_reinit(mc);
+
+    mc->smp_props.dies_supported = true;
+
+    for (i = 0; i < ARRAY_SIZE(data_generic); i++) {
+        smp_test_data_init(&data, &data_generic[i]);
+
+        /* omitted arch-specific dies should directly default to 1 */
+        data.expect_prefer_sockets.dies = 1;
+        data.expect_prefer_cores.dies = 1;
+
+        mc->smp_props.prefer_sockets = true;
+        check_smp_parse(ms, &data.config,
+                        &data.expect_prefer_sockets, NULL, true);
+
+        mc->smp_props.prefer_sockets = false;
+        check_smp_parse(ms, &data.config,
+                        &data.expect_prefer_cores, NULL, true);
+    }
+
+    /* when dies is provided in the configuration */
+    for (i = 0; i < ARRAY_SIZE(data_with_dies); i++) {
+        smp_test_data_init(&data, &data_with_dies[i]);
+
+        mc->smp_props.prefer_sockets = true;
+        check_smp_parse(ms, &data.config,
+                        &data.expect_prefer_sockets, NULL, true);
+
+        mc->smp_props.prefer_sockets = false;
+        check_smp_parse(ms, &data.config,
+                        &data.expect_prefer_cores, NULL, true);
+    }
+
+    object_unref(obj);
+}
+
+static void acceptance_generic_test(void)
+{
+    Object *obj = object_new(TYPE_MACHINE);
+    MachineState *ms = MACHINE(obj);
+    MachineClass *mc = MACHINE_GET_CLASS(obj);
+    SMPTestData *datap;
+    int i;
+
+    /* make sure that we have created the object */
+    g_assert_nonnull(ms);
+    g_assert_nonnull(mc);
+
+    /* reinitialize related machine properties before each subtest */
+    smp_machine_class_reinit(mc);
+
+    /* reset the machine supported min CPUs and max CPUs */
+    mc->min_cpus = MIN_CPUS + 1;
+    mc->max_cpus = MAX_CPUS - 1;
+
+    for (i = 0; i < ARRAY_SIZE(data_generic_invalid); i++) {
+        datap = &data_generic_invalid[i];
+        check_smp_parse(ms, &datap->config, NULL, datap->expect_error, false);
+    }
+
+    /* config: -smp 8,sockets=2,cores=4,threads=2,maxcpus=8 */
+    datap = &(SMPTestData){
+        .config = SMP_CONFIG_GENERIC(T, 8, T, 2, T, 4, T, 2, T, 8),
+        .expect_error = "Invalid CPU topology: "
+                        "product of the hierarchy must match maxcpus: "
+                        "sockets (2) * cores (4) * threads (2) "
+                        "!= maxcpus (8)",
+    };
+    check_smp_parse(ms, &datap->config, NULL, datap->expect_error, false);
+
+    /* config: -smp 18,sockets=2,cores=4,threads=2,maxcpus=16 */
+    datap = &(SMPTestData){
+        .config = SMP_CONFIG_GENERIC(T, 18, T, 2, T, 4, T, 2, T, 16),
+        .expect_error = "Invalid CPU topology: "
+                        "maxcpus must be equal to or greater than smp: "
+                        "sockets (2) * cores (4) * threads (2) "
+                        "== maxcpus (16) < smp_cpus (18)",
+    };
+    check_smp_parse(ms, &datap->config, NULL, datap->expect_error, false);
+
+    /* config: -smp 8,dies=2 */
+    datap = &(SMPTestData){
+        .config = SMP_CONFIG_WITH_DIES(T, 8, F, 0, T, 2, F, 0, F, 0, F, 0),
+        .expect_error = "dies not supported by this machine's CPU topology",
+    };
+    check_smp_parse(ms, &datap->config, NULL, datap->expect_error, false);
+
+    object_unref(obj);
+}
+
+static void acceptance_with_dies_test(void)
+{
+    Object *obj = object_new(TYPE_MACHINE);
+    MachineState *ms = MACHINE(obj);
+    MachineClass *mc = MACHINE_GET_CLASS(obj);
+    SMPTestData *datap;
+
+    /* make sure that we have created the object */
+    g_assert_nonnull(ms);
+    g_assert_nonnull(mc);
+
+    /* reinitialize related machine properties before each subtest */
+    smp_machine_class_reinit(mc);
+
+    mc->smp_props.dies_supported = true;
+
+    /* config: -smp 16,sockets=2,dies=2,cores=4,threads=2,maxcpus=16 */
+    datap = &(SMPTestData){
+        .config = SMP_CONFIG_WITH_DIES(T, 16, T, 2, T, 2, T, 4, T, 2, T, 16),
+        .expect_error = "Invalid CPU topology: "
+                        "product of the hierarchy must match maxcpus: "
+                        "sockets (2) * dies (2) * cores (4) * threads (2) "
+                        "!= maxcpus (16)",
+    };
+    check_smp_parse(ms, &datap->config, NULL, datap->expect_error, false);
+
+    /* config: -smp 34,sockets=2,dies=2,cores=4,threads=2,maxcpus=32 */
+    datap = &(SMPTestData){
+        .config = SMP_CONFIG_WITH_DIES(T, 34, T, 2, T, 2, T, 4, T, 2, T, 32),
+        .expect_error = "Invalid CPU topology: "
+                        "maxcpus must be equal to or greater than smp: "
+                        "sockets (2) * dies (2) * cores (4) * threads (2) "
+                        "== maxcpus (32) < smp_cpus (34)",
+    };
+    check_smp_parse(ms, &datap->config, NULL, datap->expect_error, false);
+
+    object_unref(obj);
+}
+
+int main(int argc, char *argv[])
+{
+    g_test_init(&argc, &argv, NULL);
+
+    module_call_init(MODULE_INIT_QOM);
+    type_register_static(&smp_machine_info);
+
+    g_test_add_func("/test-smp-parse/smp-generic", smp_generic_test);
+    g_test_add_func("/test-smp-parse/smp-with-dies", smp_with_dies_test);
+    g_test_add_func("/test-smp-parse/acceptance-generic",
+                    acceptance_generic_test);
+    g_test_add_func("/test-smp-parse/acceptance-with-dies",
+                    acceptance_with_dies_test);
+
+    g_test_run();
+
+    return 0;
+}
-- 
2.19.1