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[109.43.177.71]) by smtp.gmail.com with ESMTPSA id x11-20020a05620a448b00b0072c01a3b6aasm7401405qkp.100.2023.02.06.04.21.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Feb 2023 04:21:22 -0800 (PST) Message-ID: <92f02547-569f-2ea8-455b-585dcfaa2a74@redhat.com> Date: Mon, 6 Feb 2023 13:21:17 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 Content-Language: en-US To: Pierre Morel , qemu-s390x@nongnu.org Cc: qemu-devel@nongnu.org, borntraeger@de.ibm.com, pasic@linux.ibm.com, richard.henderson@linaro.org, david@redhat.com, cohuck@redhat.com, mst@redhat.com, pbonzini@redhat.com, kvm@vger.kernel.org, ehabkost@redhat.com, marcel.apfelbaum@gmail.com, eblake@redhat.com, armbru@redhat.com, seiden@linux.ibm.com, nrb@linux.ibm.com, nsg@linux.ibm.com, frankja@linux.ibm.com, berrange@redhat.com, clg@kaod.org References: <20230201132051.126868-1-pmorel@linux.ibm.com> <20230201132051.126868-9-pmorel@linux.ibm.com> From: Thomas Huth Subject: Re: [PATCH v15 08/11] qapi/s390x/cpu topology: x-set-cpu-topology monitor command In-Reply-To: <20230201132051.126868-9-pmorel@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-1.148, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 01/02/2023 14.20, Pierre Morel wrote: > The modification of the CPU attributes are done through a monitor > command. > > It allows to move the core inside the topology tree to optimise I'm not a native speaker, but "optimize" is more common, I think? > the cache usage in the case the host's hypervisor previously > moved the CPU. > > The same command allows to modify the CPU attributes modifiers > like polarization entitlement and the dedicated attribute to notify > the guest if the host admin modified scheduling or dedication of a vCPU. > > With this knowledge the guest has the possibility to optimize the > usage of the vCPUs. > > The command is made experimental for the moment. > > Signed-off-by: Pierre Morel > --- > qapi/machine-target.json | 29 +++++++++++++ > include/monitor/hmp.h | 1 + > hw/s390x/cpu-topology.c | 88 ++++++++++++++++++++++++++++++++++++++++ > hmp-commands.hx | 16 ++++++++ > 4 files changed, 134 insertions(+) > > diff --git a/qapi/machine-target.json b/qapi/machine-target.json > index 2e267fa458..58df0f5061 100644 > --- a/qapi/machine-target.json > +++ b/qapi/machine-target.json > @@ -342,3 +342,32 @@ > 'TARGET_S390X', > 'TARGET_MIPS', > 'TARGET_LOONGARCH64' ] } } > + > +## > +# @x-set-cpu-topology: > +# > +# @core: the vCPU ID to be moved > +# @socket: the destination socket where to move the vCPU > +# @book: the destination book where to move the vCPU > +# @drawer: the destination drawer where to move the vCPU > +# @polarity: optional polarity, default is last polarity set by the guest Hmm, below you do something like that: if (!has_polarity) { polarity = POLARITY_VERTICAL_MEDIUM; } ... so it rather seems like medium polarity is the default? ... that looks weird. I think you should maybe rather pass the has_polarity and has_dedication flags to the s390_change_topology() function and only change the value if they have really been provided? > +# @dedicated: optional, if the vCPU is dedicated to a real CPU > +# > +# Modifies the topology by moving the CPU inside the topology > +# tree or by changing a modifier attribute of a CPU. > +# > +# Returns: Nothing on success, the reason on failure. > +# > +# Since: Please replace with "Since: 8.0" ... I hope we'll get it merged during this cycle! > +{ 'command': 'x-set-cpu-topology', > + 'data': { > + 'core': 'int', > + 'socket': 'int', > + 'book': 'int', > + 'drawer': 'int', > + '*polarity': 'int', > + '*dedicated': 'bool' > + }, > + 'if': { 'all': [ 'TARGET_S390X', 'CONFIG_KVM' ] } > +} > diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h > index 1b3bdcb446..12827479cf 100644 > --- a/include/monitor/hmp.h > +++ b/include/monitor/hmp.h > @@ -151,5 +151,6 @@ void hmp_human_readable_text_helper(Monitor *mon, > HumanReadableText *(*qmp_handler)(Error **)); > void hmp_info_stats(Monitor *mon, const QDict *qdict); > void hmp_pcie_aer_inject_error(Monitor *mon, const QDict *qdict); > +void hmp_x_set_cpu_topology(Monitor *mon, const QDict *qdict); > > #endif > diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c > index c33378577b..6c50050991 100644 > --- a/hw/s390x/cpu-topology.c > +++ b/hw/s390x/cpu-topology.c > @@ -18,6 +18,10 @@ > #include "target/s390x/cpu.h" > #include "hw/s390x/s390-virtio-ccw.h" > #include "hw/s390x/cpu-topology.h" > +#include "qapi/qapi-commands-machine-target.h" > +#include "qapi/qmp/qdict.h" > +#include "monitor/hmp.h" > +#include "monitor/monitor.h" > > /* > * s390_topology is used to keep the topology information. > @@ -379,3 +383,87 @@ void s390_topology_set_cpu(MachineState *ms, S390CPU *cpu, Error **errp) > /* topology tree is reflected in props */ > s390_update_cpu_props(ms, cpu); > } > + > +/* > + * qmp and hmp implementations > + */ > + > +static void s390_change_topology(int64_t core_id, int64_t socket_id, > + int64_t book_id, int64_t drawer_id, > + int64_t polarity, bool dedicated, > + Error **errp) > +{ > + MachineState *ms = current_machine; > + S390CPU *cpu; > + ERRP_GUARD(); > + > + cpu = (S390CPU *)ms->possible_cpus->cpus[core_id].cpu; I think you should add a sanity check for core_id being in a valid range ... otherwise this will cause an access beyond the end of the array if core_id is too big or negative. > + if (!cpu) { > + error_setg(errp, "Core-id %ld does not exist!", core_id); > + return; > + } > + > + /* Verify the new topology */ > + s390_topology_check(cpu, errp); > + if (*errp) { > + return; > + } > + > + /* Move the CPU into its new socket */ > + s390_set_core_in_socket(cpu, drawer_id, book_id, socket_id, true, errp); > + > + /* All checks done, report topology in environment */ > + cpu->env.drawer_id = drawer_id; > + cpu->env.book_id = book_id; > + cpu->env.socket_id = socket_id; > + cpu->env.dedicated = dedicated; > + cpu->env.entitlement = polarity; As mentioned above, I think dedicated and polarity should only be changed if they have really been provided? > + /* topology tree is reflected in props */ > + s390_update_cpu_props(ms, cpu); > + > + /* Advertise the topology change */ > + s390_cpu_topology_set_modified(); > +} > + > +void qmp_x_set_cpu_topology(int64_t core, int64_t socket, > + int64_t book, int64_t drawer, > + bool has_polarity, int64_t polarity, > + bool has_dedicated, bool dedicated, > + Error **errp) > +{ > + ERRP_GUARD(); > + > + if (!s390_has_topology()) { > + error_setg(errp, "This machine doesn't support topology"); > + return; > + } > + if (!has_polarity) { > + polarity = POLARITY_VERTICAL_MEDIUM; > + } > + if (!has_dedicated) { > + dedicated = false; > + } > + s390_change_topology(core, socket, book, drawer, polarity, dedicated, errp); > +} > + > +void hmp_x_set_cpu_topology(Monitor *mon, const QDict *qdict) > +{ > + const int64_t core = qdict_get_int(qdict, "core"); > + const int64_t socket = qdict_get_int(qdict, "socket"); > + const int64_t book = qdict_get_int(qdict, "book"); > + const int64_t drawer = qdict_get_int(qdict, "drawer"); > + bool has_polarity = qdict_haskey(qdict, "polarity"); > + const int64_t polarity = qdict_get_try_int(qdict, "polarity", 0); > + bool has_dedicated = qdict_haskey(qdict, "dedicated"); > + const bool dedicated = qdict_get_try_bool(qdict, "dedicated", false); > + Error *local_err = NULL; > + > + qmp_x_set_cpu_topology(core, socket, book, drawer, > + has_polarity, polarity, > + has_dedicated, dedicated, > + &local_err); > + if (hmp_handle_error(mon, local_err)) { > + return; > + } > +} > diff --git a/hmp-commands.hx b/hmp-commands.hx > index 673e39a697..bb3c908356 100644 > --- a/hmp-commands.hx > +++ b/hmp-commands.hx > @@ -1815,3 +1815,19 @@ SRST > Dump the FDT in dtb format to *filename*. > ERST > #endif > + > +#if defined(TARGET_S390X) && defined(CONFIG_KVM) > + { > + .name = "x-set-cpu-topology", > + .args_type = "core:l,socket:l,book:l,drawer:l,polarity:l?,dedicated:b?", > + .params = "core socket book drawer [polarity] [dedicated]", > + .help = "Move CPU 'core' to 'socket/book/drawer' " > + "optionaly modifies polarity and dedication", optionaly ==> optionally > + .cmd = hmp_x_set_cpu_topology, > + }, > + > +SRST > +``x-set-cpu-topology`` *core* *socket* *book* *drawer* *polarity* *dedicated* > + Moves the CPU *core* to *socket* *book* *drawer* with *polarity* *dedicated*. > +ERST > +#endif Thomas