1 /* 2 * QEMU Machine core (related to -smp parsing) 3 * 4 * Copyright (c) 2021 Huawei Technologies Co., Ltd 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, 9 * or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include "qemu/osdep.h" 21 #include "hw/boards.h" 22 #include "qapi/error.h" 23 #include "qemu/error-report.h" 24 25 26 /* 27 * Report information of a machine's supported CPU topology hierarchy. 28 * Topology members will be ordered from the largest to the smallest 29 * in the string. 30 */ 31 static char *cpu_hierarchy_to_string(MachineState *ms) 32 { 33 MachineClass *mc = MACHINE_GET_CLASS(ms); 34 GString *s = g_string_new(NULL); 35 36 g_string_append_printf(s, "sockets (%u)", ms->smp.sockets); 37 38 if (mc->smp_props.dies_supported) { 39 g_string_append_printf(s, " * dies (%u)", ms->smp.dies); 40 } 41 42 if (mc->smp_props.clusters_supported) { 43 g_string_append_printf(s, " * clusters (%u)", ms->smp.clusters); 44 } 45 46 g_string_append_printf(s, " * cores (%u)", ms->smp.cores); 47 g_string_append_printf(s, " * threads (%u)", ms->smp.threads); 48 49 return g_string_free(s, false); 50 } 51 52 /* 53 * machine_parse_smp_config: Generic function used to parse the given 54 * SMP configuration 55 * 56 * Any missing parameter in "cpus/maxcpus/sockets/cores/threads" will be 57 * automatically computed based on the provided ones. 58 * 59 * In the calculation of omitted sockets/cores/threads: we prefer sockets 60 * over cores over threads before 6.2, while preferring cores over sockets 61 * over threads since 6.2. 62 * 63 * In the calculation of cpus/maxcpus: When both maxcpus and cpus are omitted, 64 * maxcpus will be computed from the given parameters and cpus will be set 65 * equal to maxcpus. When only one of maxcpus and cpus is given then the 66 * omitted one will be set to its given counterpart's value. Both maxcpus and 67 * cpus may be specified, but maxcpus must be equal to or greater than cpus. 68 * 69 * For compatibility, apart from the parameters that will be computed, newly 70 * introduced topology members which are likely to be target specific should 71 * be directly set as 1 if they are omitted (e.g. dies for PC since 4.1). 72 */ 73 void machine_parse_smp_config(MachineState *ms, 74 const SMPConfiguration *config, Error **errp) 75 { 76 MachineClass *mc = MACHINE_GET_CLASS(ms); 77 unsigned cpus = config->has_cpus ? config->cpus : 0; 78 unsigned sockets = config->has_sockets ? config->sockets : 0; 79 unsigned dies = config->has_dies ? config->dies : 0; 80 unsigned clusters = config->has_clusters ? config->clusters : 0; 81 unsigned cores = config->has_cores ? config->cores : 0; 82 unsigned threads = config->has_threads ? config->threads : 0; 83 unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0; 84 85 /* 86 * Specified CPU topology parameters must be greater than zero, 87 * explicit configuration like "cpus=0" is not allowed. 88 */ 89 if ((config->has_cpus && config->cpus == 0) || 90 (config->has_sockets && config->sockets == 0) || 91 (config->has_dies && config->dies == 0) || 92 (config->has_clusters && config->clusters == 0) || 93 (config->has_cores && config->cores == 0) || 94 (config->has_threads && config->threads == 0) || 95 (config->has_maxcpus && config->maxcpus == 0)) { 96 warn_report("Deprecated CPU topology (considered invalid): " 97 "CPU topology parameters must be greater than zero"); 98 } 99 100 /* 101 * If not supported by the machine, a topology parameter must be 102 * omitted or specified equal to 1. 103 */ 104 if (!mc->smp_props.dies_supported && dies > 1) { 105 error_setg(errp, "dies not supported by this machine's CPU topology"); 106 return; 107 } 108 if (!mc->smp_props.clusters_supported && clusters > 1) { 109 error_setg(errp, "clusters not supported by this machine's CPU topology"); 110 return; 111 } 112 113 dies = dies > 0 ? dies : 1; 114 clusters = clusters > 0 ? clusters : 1; 115 116 /* compute missing values based on the provided ones */ 117 if (cpus == 0 && maxcpus == 0) { 118 sockets = sockets > 0 ? sockets : 1; 119 cores = cores > 0 ? cores : 1; 120 threads = threads > 0 ? threads : 1; 121 } else { 122 maxcpus = maxcpus > 0 ? maxcpus : cpus; 123 124 if (mc->smp_props.prefer_sockets) { 125 /* prefer sockets over cores before 6.2 */ 126 if (sockets == 0) { 127 cores = cores > 0 ? cores : 1; 128 threads = threads > 0 ? threads : 1; 129 sockets = maxcpus / (dies * clusters * cores * threads); 130 } else if (cores == 0) { 131 threads = threads > 0 ? threads : 1; 132 cores = maxcpus / (sockets * dies * clusters * threads); 133 } 134 } else { 135 /* prefer cores over sockets since 6.2 */ 136 if (cores == 0) { 137 sockets = sockets > 0 ? sockets : 1; 138 threads = threads > 0 ? threads : 1; 139 cores = maxcpus / (sockets * dies * clusters * threads); 140 } else if (sockets == 0) { 141 threads = threads > 0 ? threads : 1; 142 sockets = maxcpus / (dies * clusters * cores * threads); 143 } 144 } 145 146 /* try to calculate omitted threads at last */ 147 if (threads == 0) { 148 threads = maxcpus / (sockets * dies * clusters * cores); 149 } 150 } 151 152 maxcpus = maxcpus > 0 ? maxcpus : sockets * dies * clusters * cores * threads; 153 cpus = cpus > 0 ? cpus : maxcpus; 154 155 ms->smp.cpus = cpus; 156 ms->smp.sockets = sockets; 157 ms->smp.dies = dies; 158 ms->smp.clusters = clusters; 159 ms->smp.cores = cores; 160 ms->smp.threads = threads; 161 ms->smp.max_cpus = maxcpus; 162 163 mc->smp_props.has_clusters = config->has_clusters; 164 165 /* sanity-check of the computed topology */ 166 if (sockets * dies * clusters * cores * threads != maxcpus) { 167 g_autofree char *topo_msg = cpu_hierarchy_to_string(ms); 168 error_setg(errp, "Invalid CPU topology: " 169 "product of the hierarchy must match maxcpus: " 170 "%s != maxcpus (%u)", 171 topo_msg, maxcpus); 172 return; 173 } 174 175 if (maxcpus < cpus) { 176 g_autofree char *topo_msg = cpu_hierarchy_to_string(ms); 177 error_setg(errp, "Invalid CPU topology: " 178 "maxcpus must be equal to or greater than smp: " 179 "%s == maxcpus (%u) < smp_cpus (%u)", 180 topo_msg, maxcpus, cpus); 181 return; 182 } 183 184 if (ms->smp.cpus < mc->min_cpus) { 185 error_setg(errp, "Invalid SMP CPUs %d. The min CPUs " 186 "supported by machine '%s' is %d", 187 ms->smp.cpus, 188 mc->name, mc->min_cpus); 189 return; 190 } 191 192 if (ms->smp.max_cpus > mc->max_cpus) { 193 error_setg(errp, "Invalid SMP CPUs %d. The max CPUs " 194 "supported by machine '%s' is %d", 195 ms->smp.max_cpus, 196 mc->name, mc->max_cpus); 197 return; 198 } 199 } 200