/* * QEMU Machine core (related to -smp parsing) * * 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 . */ #include "qemu/osdep.h" #include "hw/boards.h" #include "qapi/error.h" /* * Report information of a machine's supported CPU topology hierarchy. * Topology members will be ordered from the largest to the smallest * in the string. */ static char *cpu_hierarchy_to_string(MachineState *ms) { MachineClass *mc = MACHINE_GET_CLASS(ms); GString *s = g_string_new(NULL); g_string_append_printf(s, "sockets (%u)", ms->smp.sockets); if (mc->smp_props.dies_supported) { g_string_append_printf(s, " * dies (%u)", ms->smp.dies); } g_string_append_printf(s, " * cores (%u)", ms->smp.cores); g_string_append_printf(s, " * threads (%u)", ms->smp.threads); return g_string_free(s, false); } /* * smp_parse - Generic function used to parse the given SMP configuration * * Any missing parameter in "cpus/maxcpus/sockets/cores/threads" will be * automatically computed based on the provided ones. * * In the 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. * * In the calculation of cpus/maxcpus: 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. * * For compatibility, apart from the parameters that will be computed, newly * introduced topology members which are likely to be target specific should * be directly set as 1 if they are omitted (e.g. dies for PC since 4.1). */ 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("Deprecated CPU topology (considered invalid): " "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; } 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_hierarchy_to_string(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_hierarchy_to_string(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; } }