hw/core/machine-smp.c

   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     if (mc->smp_props.drawers_supported) {
  37         g_string_append_printf(s, "drawers (%u) * ", ms->smp.drawers);
  38     }
  39
  40     if (mc->smp_props.books_supported) {
  41         g_string_append_printf(s, "books (%u) * ", ms->smp.books);
  42     }
  43
  44     g_string_append_printf(s, "sockets (%u)", ms->smp.sockets);
  45
  46     if (mc->smp_props.dies_supported) {
  47         g_string_append_printf(s, " * dies (%u)", ms->smp.dies);
  48     }
  49
  50     if (mc->smp_props.clusters_supported) {
  51         g_string_append_printf(s, " * clusters (%u)", ms->smp.clusters);
  52     }
  53
  54     if (mc->smp_props.modules_supported) {
  55         g_string_append_printf(s, " * modules (%u)", ms->smp.modules);
  56     }
  57
  58     g_string_append_printf(s, " * cores (%u)", ms->smp.cores);
  59     g_string_append_printf(s, " * threads (%u)", ms->smp.threads);
  60
  61     return g_string_free(s, false);
  62 }
  63
  64 /*
  65  * machine_parse_smp_config: Generic function used to parse the given
  66  *                           SMP configuration
  67  *
  68  * Any missing parameter in "cpus/maxcpus/sockets/cores/threads" will be
  69  * automatically computed based on the provided ones.
  70  *
  71  * In the calculation of omitted sockets/cores/threads: we prefer sockets
  72  * over cores over threads before 6.2, while preferring cores over sockets
  73  * over threads since 6.2.
  74  *
  75  * In the calculation of cpus/maxcpus: When both maxcpus and cpus are omitted,
  76  * maxcpus will be computed from the given parameters and cpus will be set
  77  * equal to maxcpus. When only one of maxcpus and cpus is given then the
  78  * omitted one will be set to its given counterpart's value. Both maxcpus and
  79  * cpus may be specified, but maxcpus must be equal to or greater than cpus.
  80  *
  81  * For compatibility, apart from the parameters that will be computed, newly
  82  * introduced topology members which are likely to be target specific should
  83  * be directly set as 1 if they are omitted (e.g. dies for PC since 4.1).
  84  */
  85 void machine_parse_smp_config(MachineState *ms,
  86                               const SMPConfiguration *config, Error **errp)
  87 {
  88     MachineClass *mc = MACHINE_GET_CLASS(ms);
  89     unsigned cpus    = config->has_cpus ? config->cpus : 0;
  90     unsigned drawers = config->has_drawers ? config->drawers : 0;
  91     unsigned books   = config->has_books ? config->books : 0;
  92     unsigned sockets = config->has_sockets ? config->sockets : 0;
  93     unsigned dies    = config->has_dies ? config->dies : 0;
  94     unsigned clusters = config->has_clusters ? config->clusters : 0;
  95     unsigned modules = config->has_modules ? config->modules : 0;
  96     unsigned cores   = config->has_cores ? config->cores : 0;
  97     unsigned threads = config->has_threads ? config->threads : 0;
  98     unsigned maxcpus = config->has_maxcpus ? config->maxcpus : 0;
  99     unsigned total_cpus;
 100
 101     /*
 102      * Specified CPU topology parameters must be greater than zero,
 103      * explicit configuration like "cpus=0" is not allowed.
 104      */
 105     if ((config->has_cpus && config->cpus == 0) ||
 106         (config->has_drawers && config->drawers == 0) ||
 107         (config->has_books && config->books == 0) ||
 108         (config->has_sockets && config->sockets == 0) ||
 109         (config->has_dies && config->dies == 0) ||
 110         (config->has_clusters && config->clusters == 0) ||
 111         (config->has_modules && config->modules == 0) ||
 112         (config->has_cores && config->cores == 0) ||
 113         (config->has_threads && config->threads == 0) ||
 114         (config->has_maxcpus && config->maxcpus == 0)) {
 115         error_setg(errp, "Invalid CPU topology: "
 116                    "CPU topology parameters must be greater than zero");
 117         return;
 118     }
 119
 120     /*
 121      * If not supported by the machine, a topology parameter must
 122      * not be set to a value greater than 1.
 123      */
 124     if (!mc->smp_props.modules_supported &&
 125         config->has_modules && config->modules > 1) {
 126         error_setg(errp,
 127                    "modules > 1 not supported by this machine's CPU topology");
 128         return;
 129     }
 130     modules = modules > 0 ? modules : 1;
 131
 132     if (!mc->smp_props.clusters_supported &&
 133         config->has_clusters && config->clusters > 1) {
 134         error_setg(errp,
 135                    "clusters > 1 not supported by this machine's CPU topology");
 136         return;
 137     }
 138     clusters = clusters > 0 ? clusters : 1;
 139
 140     if (!mc->smp_props.dies_supported &&
 141         config->has_dies && config->dies > 1) {
 142         error_setg(errp,
 143                    "dies > 1 not supported by this machine's CPU topology");
 144         return;
 145     }
 146     dies = dies > 0 ? dies : 1;
 147
 148     if (!mc->smp_props.books_supported &&
 149         config->has_books && config->books > 1) {
 150         error_setg(errp,
 151                    "books > 1 not supported by this machine's CPU topology");
 152         return;
 153     }
 154     books = books > 0 ? books : 1;
 155
 156     if (!mc->smp_props.drawers_supported &&
 157         config->has_drawers && config->drawers > 1) {
 158         error_setg(errp,
 159                    "drawers > 1 not supported by this machine's CPU topology");
 160         return;
 161     }
 162     drawers = drawers > 0 ? drawers : 1;
 163
 164     /* compute missing values based on the provided ones */
 165     if (cpus == 0 && maxcpus == 0) {
 166         sockets = sockets > 0 ? sockets : 1;
 167         cores = cores > 0 ? cores : 1;
 168         threads = threads > 0 ? threads : 1;
 169     } else {
 170         maxcpus = maxcpus > 0 ? maxcpus : cpus;
 171
 172         if (mc->smp_props.prefer_sockets) {
 173             /* prefer sockets over cores before 6.2 */
 174             if (sockets == 0) {
 175                 cores = cores > 0 ? cores : 1;
 176                 threads = threads > 0 ? threads : 1;
 177                 sockets = maxcpus /
 178                           (drawers * books * dies * clusters *
 179                            modules * cores * threads);
 180             } else if (cores == 0) {
 181                 threads = threads > 0 ? threads : 1;
 182                 cores = maxcpus /
 183                         (drawers * books * sockets * dies *
 184                          clusters * modules * threads);
 185             }
 186         } else {
 187             /* prefer cores over sockets since 6.2 */
 188             if (cores == 0) {
 189                 sockets = sockets > 0 ? sockets : 1;
 190                 threads = threads > 0 ? threads : 1;
 191                 cores = maxcpus /
 192                         (drawers * books * sockets * dies *
 193                          clusters * modules * threads);
 194             } else if (sockets == 0) {
 195                 threads = threads > 0 ? threads : 1;
 196                 sockets = maxcpus /
 197                           (drawers * books * dies * clusters *
 198                            modules * cores * threads);
 199             }
 200         }
 201
 202         /* try to calculate omitted threads at last */
 203         if (threads == 0) {
 204             threads = maxcpus /
 205                       (drawers * books * sockets * dies *
 206                        clusters * modules * cores);
 207         }
 208     }
 209
 210     total_cpus = drawers * books * sockets * dies *
 211                  clusters * modules * cores * threads;
 212     maxcpus = maxcpus > 0 ? maxcpus : total_cpus;
 213     cpus = cpus > 0 ? cpus : maxcpus;
 214
 215     ms->smp.cpus = cpus;
 216     ms->smp.drawers = drawers;
 217     ms->smp.books = books;
 218     ms->smp.sockets = sockets;
 219     ms->smp.dies = dies;
 220     ms->smp.clusters = clusters;
 221     ms->smp.modules = modules;
 222     ms->smp.cores = cores;
 223     ms->smp.threads = threads;
 224     ms->smp.max_cpus = maxcpus;
 225
 226     mc->smp_props.has_clusters = config->has_clusters;
 227
 228     /* sanity-check of the computed topology */
 229     if (total_cpus != maxcpus) {
 230         g_autofree char *topo_msg = cpu_hierarchy_to_string(ms);
 231         error_setg(errp, "Invalid CPU topology: "
 232                    "product of the hierarchy must match maxcpus: "
 233                    "%s != maxcpus (%u)",
 234                    topo_msg, maxcpus);
 235         return;
 236     }
 237
 238     if (maxcpus < cpus) {
 239         g_autofree char *topo_msg = cpu_hierarchy_to_string(ms);
 240         error_setg(errp, "Invalid CPU topology: "
 241                    "maxcpus must be equal to or greater than smp: "
 242                    "%s == maxcpus (%u) < smp_cpus (%u)",
 243                    topo_msg, maxcpus, cpus);
 244         return;
 245     }
 246
 247     if (ms->smp.cpus < mc->min_cpus) {
 248         error_setg(errp, "Invalid SMP CPUs %d. The min CPUs "
 249                    "supported by machine '%s' is %d",
 250                    ms->smp.cpus,
 251                    mc->name, mc->min_cpus);
 252         return;
 253     }
 254
 255     if (ms->smp.max_cpus > mc->max_cpus) {
 256         error_setg(errp, "Invalid SMP CPUs %d. The max CPUs "
 257                    "supported by machine '%s' is %d",
 258                    ms->smp.max_cpus,
 259                    mc->name, mc->max_cpus);
 260         return;
 261     }
 262 }
 263
 264 unsigned int machine_topo_get_cores_per_socket(const MachineState *ms)
 265 {
 266     return ms->smp.cores * ms->smp.modules * ms->smp.clusters * ms->smp.dies;
 267 }
 268
 269 unsigned int machine_topo_get_threads_per_socket(const MachineState *ms)
 270 {
 271     return ms->smp.threads * machine_topo_get_cores_per_socket(ms);
 272 }