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author | Yanan Wang <wangyanan55@huawei.com> | 2021-09-29 10:58:02 +0800 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-10-01 15:27:56 +0200 |
commit | c2511b1632e109130df524121dfb7d2413216d3c (patch) | |
tree | 57a0a342ab04a4d7a8917b7e7413afbeb6c4226b | |
parent | 7237c7ce772794d6be10b8b987fe4d02dfd76562 (diff) | |
download | qemu-c2511b1632e109130df524121dfb7d2413216d3c.zip qemu-c2511b1632e109130df524121dfb7d2413216d3c.tar.gz qemu-c2511b1632e109130df524121dfb7d2413216d3c.tar.bz2 |
machine: Deprecate "parameter=0" SMP configurations
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>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210929025816.21076-3-wangyanan55@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r-- | docs/about/deprecated.rst | 15 | ||||
-rw-r--r-- | hw/core/machine.c | 14 | ||||
-rw-r--r-- | qemu-options.hx | 12 |
3 files changed, 36 insertions, 5 deletions
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 2f7db9a..0bed6ec 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -160,6 +160,21 @@ Use ``-display sdl`` instead. Use ``-display curses`` 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. Plugin argument passing through ``arg=<string>`` (since 6.1) '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' diff --git a/hw/core/machine.c b/hw/core/machine.c index 067f42b..4e40926 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -835,6 +835,20 @@ 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("Deprecated CPU topology (considered invalid): " + "CPU topology parameters must be greater than zero"); + } + mc->smp_parse(ms, config, errp); if (*errp) { goto out_free; diff --git a/qemu-options.hx b/qemu-options.hx index ceca528..4a092a0 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -233,11 +233,13 @@ 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, |