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 24 /* 25 * Report information of a machine's supported CPU topology hierarchy. 26 * Topology members will be ordered from the largest to the smallest 27 * in the string. 28 */ 29 static char *cpu_hierarchy_to_string(MachineState *ms) 30 { 31 MachineClass *mc = MACHINE_GET_CLASS(ms); 32 GString *s = g_string_new(NULL); 33 34 g_string_append_printf(s, "sockets (%u)", ms->smp.sockets); 35 36 if (mc->smp_props.dies_supported) { 37 g_string_append_printf(s, " * dies (%u)", ms->smp.dies); 38 } 39 40 if (mc->smp_props.clusters_supported) { 41 g_string_append_printf(s, " * clusters (%u)", ms->smp.clusters); 42 } 43 44 g_string_append_printf(s, " * cores (%u)", ms->smp.cores); 45 g_string_append_printf(s, " * threads (%u)", ms->smp.threads); 46 47 return g_string_free(s, false); 48 } 49 50 /* 51 * machine_parse_smp_config: Generic function used to parse the given 52 * SMP configuration 53 * 54 * Any missing parameter in "cpus/maxcpus/sockets/cores/threads" will be 55 * automatically computed based on the provided ones. 56 * 57 * In the calculation of omitted sockets/cores/threads: we prefer sockets 58 * over cores over threads before 6.2, while preferring cores over sockets 59 * over threads since 6.2. 60 * 61 * In the calculation of cpus/maxcpus: When both maxcpus and cpus are omitted, 62 * maxcpus will be computed from the given parameters and cpus will be set 63 * equal to maxcpus. When only one of maxcpus and cpus is given then the 64 * omitted one will be set to its given counterpart's value. Both maxcpus and 65 * cpus may be specified, but maxcpus must be equal to or greater than cpus. 66 * 67 * For compatibility, apart from the parameters that will be computed, newly 68 * introduced topology members which are likely to be target specific should 69 * be directly set as 1 if they are omitted (e.g. dies for PC since 4.1). 70 */ 71 void machine_parse_smp_config(MachineState *ms, 72 const SMPConfiguration *config, Error **errp) 73 { 74 MachineClass *mc = MACHINE_GET_CLASS(ms); 75 unsigned cpus = config->has_cpus ? config->cpus : 0; 76 unsigned sockets = config->has_sockets ? config->sockets : 0; 77 unsigned dies = config->has_dies ? config->dies : 0; 78 unsigned clusters = config->has_clusters ? config->clusters : 0; 79 unsigned cores = config->has_cores ? config->cores : 0; 80 unsigned threads = config->has_threads ? config->threads : 0; 81 unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0; 82 83 /* 84 * Specified CPU topology parameters must be greater than zero, 85 * explicit configuration like "cpus=0" is not allowed. 86 */ 87 if ((config->has_cpus && config->cpus == 0) || 88 (config->has_sockets && config->sockets == 0) || 89 (config->has_dies && config->dies == 0) || 90 (config->has_clusters && config->clusters == 0) || 91 (config->has_cores && config->cores == 0) || 92 (config->has_threads && config->threads == 0) || 93 (config->has_maxcpus && config->maxcpus == 0)) { 94 warn_report("Deprecated CPU topology (considered invalid): " 95 "CPU topology parameters must be greater than zero"); 96 } 97 98 /* 99 * If not supported by the machine, a topology parameter must be 100 * omitted or specified equal to 1. 101 */ 102 if (!mc->smp_props.dies_supported && dies > 1) { 103 error_setg(errp, "dies not supported by this machine's CPU topology"); 104 return; 105 } 106 if (!mc->smp_props.clusters_supported && clusters > 1) { 107 error_setg(errp, "clusters not supported by this machine's CPU topology"); 108 return; 109 } 110 111 dies = dies > 0 ? dies : 1; 112 clusters = clusters > 0 ? clusters : 1; 113 114 /* compute missing values based on the provided ones */ 115 if (cpus == 0 && maxcpus == 0) { 116 sockets = sockets > 0 ? sockets : 1; 117 cores = cores > 0 ? cores : 1; 118 threads = threads > 0 ? threads : 1; 119 } else { 120 maxcpus = maxcpus > 0 ? maxcpus : cpus; 121 122 if (mc->smp_props.prefer_sockets) { 123 /* prefer sockets over cores before 6.2 */ 124 if (sockets == 0) { 125 cores = cores > 0 ? cores : 1; 126 threads = threads > 0 ? threads : 1; 127 sockets = maxcpus / (dies * clusters * cores * threads); 128 } else if (cores == 0) { 129 threads = threads > 0 ? threads : 1; 130 cores = maxcpus / (sockets * dies * clusters * threads); 131 } 132 } else { 133 /* prefer cores over sockets since 6.2 */ 134 if (cores == 0) { 135 sockets = sockets > 0 ? sockets : 1; 136 threads = threads > 0 ? threads : 1; 137 cores = maxcpus / (sockets * dies * clusters * threads); 138 } else if (sockets == 0) { 139 threads = threads > 0 ? threads : 1; 140 sockets = maxcpus / (dies * clusters * cores * threads); 141 } 142 } 143 144 /* try to calculate omitted threads at last */ 145 if (threads == 0) { 146 threads = maxcpus / (sockets * dies * clusters * cores); 147 } 148 } 149 150 maxcpus = maxcpus > 0 ? maxcpus : sockets * dies * clusters * cores * threads; 151 cpus = cpus > 0 ? cpus : maxcpus; 152 153 ms->smp.cpus = cpus; 154 ms->smp.sockets = sockets; 155 ms->smp.dies = dies; 156 ms->smp.clusters = clusters; 157 ms->smp.cores = cores; 158 ms->smp.threads = threads; 159 ms->smp.max_cpus = maxcpus; 160 161 mc->smp_props.has_clusters = config->has_clusters; 162 163 /* sanity-check of the computed topology */ 164 if (sockets * dies * clusters * cores * threads != maxcpus) { 165 g_autofree char *topo_msg = cpu_hierarchy_to_string(ms); 166 error_setg(errp, "Invalid CPU topology: " 167 "product of the hierarchy must match maxcpus: " 168 "%s != maxcpus (%u)", 169 topo_msg, maxcpus); 170 return; 171 } 172 173 if (maxcpus < cpus) { 174 g_autofree char *topo_msg = cpu_hierarchy_to_string(ms); 175 error_setg(errp, "Invalid CPU topology: " 176 "maxcpus must be equal to or greater than smp: " 177 "%s == maxcpus (%u) < smp_cpus (%u)", 178 topo_msg, maxcpus, cpus); 179 return; 180 } 181 182 if (ms->smp.cpus < mc->min_cpus) { 183 error_setg(errp, "Invalid SMP CPUs %d. The min CPUs " 184 "supported by machine '%s' is %d", 185 ms->smp.cpus, 186 mc->name, mc->min_cpus); 187 return; 188 } 189 190 if (ms->smp.max_cpus > mc->max_cpus) { 191 error_setg(errp, "Invalid SMP CPUs %d. The max CPUs " 192 "supported by machine '%s' is %d", 193 ms->smp.max_cpus, 194 mc->name, mc->max_cpus); 195 return; 196 } 197 } 198