Re: [PATCH v6 11/11] smp: drop support for deprecated (invalid topologies)

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 23 Sep 2020 05:46:50 -0400
Igor Mammedov <imammedo@redhat.com> wrote:

> it's was deprecated since 3.1
> 
> Support for invalid topologies is removed, the user must ensure
> that topologies described with -smp include all possible cpus,
> i.e. (sockets * cores * threads) == maxcpus or QEMU will
> exit with error.

ignore this stowaway, it's not part of the series 


> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
>  docs/system/deprecated.rst | 26 +++++++++++++-------------
>  hw/core/machine.c          | 16 ++++------------
>  hw/i386/pc.c               | 16 ++++------------
>  3 files changed, 21 insertions(+), 37 deletions(-)
> 
> diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
> index 808c334fe7..fb95d2ecc4 100644
> --- a/docs/system/deprecated.rst
> +++ b/docs/system/deprecated.rst
> @@ -47,19 +47,6 @@ 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
>  for these file types is 'host_cdrom' or 'host_device' as appropriate.
>  
> -``-smp`` (invalid topologies) (since 3.1)
> -'''''''''''''''''''''''''''''''''''''''''
> -
> -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 will be removed, the user must ensure
> -topologies described with -smp include all possible cpus, i.e.
> -*sockets* * *cores* * *threads* = *maxcpus*.
> -
>  ``-vnc acl`` (since 4.0.0)
>  ''''''''''''''''''''''''''
>  
> @@ -642,6 +629,19 @@ New machine versions (since 5.1) will not accept the option but it will still
>  work with old machine types. User can check the QAPI schema to see if the legacy
>  option is supported by looking at MachineInfo::numa-mem-supported property.
>  
> +``-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*.
> +
>  Block devices
>  -------------
>  
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index ea26d61237..09aee4ea52 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -754,23 +754,15 @@ static void smp_parse(MachineState *ms, QemuOpts *opts)
>              exit(1);
>          }
>  
> -        if (sockets * cores * threads > ms->smp.max_cpus) {
> -            error_report("cpu topology: "
> -                         "sockets (%u) * cores (%u) * threads (%u) > "
> -                         "maxcpus (%u)",
> +        if (sockets * cores * threads != ms->smp.max_cpus) {
> +            error_report("Invalid CPU topology: "
> +                         "sockets (%u) * cores (%u) * threads (%u) "
> +                         "!= maxcpus (%u)",
>                           sockets, cores, threads,
>                           ms->smp.max_cpus);
>              exit(1);
>          }
>  
> -        if (sockets * cores * threads != ms->smp.max_cpus) {
> -            warn_report("Invalid CPU topology deprecated: "
> -                        "sockets (%u) * cores (%u) * threads (%u) "
> -                        "!= maxcpus (%u)",
> -                        sockets, cores, threads,
> -                        ms->smp.max_cpus);
> -        }
> -
>          ms->smp.cpus = cpus;
>          ms->smp.cores = cores;
>          ms->smp.threads = threads;
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 2af660c55e..53e21a186d 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -748,23 +748,15 @@ void pc_smp_parse(MachineState *ms, QemuOpts *opts)
>              exit(1);
>          }
>  
> -        if (sockets * dies * cores * threads > ms->smp.max_cpus) {
> -            error_report("cpu topology: "
> -                         "sockets (%u) * dies (%u) * cores (%u) * threads (%u) > "
> -                         "maxcpus (%u)",
> +        if (sockets * dies * cores * threads != ms->smp.max_cpus) {
> +            error_report("Invalid CPU topology deprecated: "
> +                         "sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
> +                         "!= maxcpus (%u)",
>                           sockets, dies, cores, threads,
>                           ms->smp.max_cpus);
>              exit(1);
>          }
>  
> -        if (sockets * dies * cores * threads != ms->smp.max_cpus) {
> -            warn_report("Invalid CPU topology deprecated: "
> -                        "sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
> -                        "!= maxcpus (%u)",
> -                        sockets, dies, cores, threads,
> -                        ms->smp.max_cpus);
> -        }
> -
>          ms->smp.cpus = cpus;
>          ms->smp.cores = cores;
>          ms->smp.threads = threads;