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