hw/s390x/cpu-topology.c

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * CPU Topology
   4  *
   5  * Copyright IBM Corp. 2022, 2023
   6  * Author(s): Pierre Morel <pmorel@linux.ibm.com>
   7  *
   8  * S390 topology handling can be divided in two parts:
   9  *
  10  * - The first part in this file is taking care of all common functions
  11  *   used by KVM and TCG to create and modify the topology.
  12  *
  13  * - The second part, building the topology information data for the
  14  *   guest with CPU and KVM specificity will be implemented inside
  15  *   the target/s390/kvm sub tree.
  16  */
  17
  18 #include "qemu/osdep.h"
  19 #include "qapi/error.h"
  20 #include "qemu/error-report.h"
  21 #include "hw/qdev-properties.h"
  22 #include "hw/boards.h"
  23 #include "target/s390x/cpu.h"
  24 #include "hw/s390x/s390-virtio-ccw.h"
  25 #include "hw/s390x/cpu-topology.h"
  26 #include "qapi/qapi-commands-machine-target.h"
  27 #include "qapi/qapi-events-machine-target.h"
  28
  29 /*
  30  * s390_topology is used to keep the topology information.
  31  * .cores_per_socket: tracks information on the count of cores
  32  *                    per socket.
  33  * .polarization: tracks machine polarization.
  34  */
  35 S390Topology s390_topology = {
  36     /* will be initialized after the CPU model is realized */
  37     .cores_per_socket = NULL,
  38     .polarization = S390_CPU_POLARIZATION_HORIZONTAL,
  39 };
  40
  41 /**
  42  * s390_socket_nb:
  43  * @cpu: s390x CPU
  44  *
  45  * Returns the socket number used inside the cores_per_socket array
  46  * for a topology tree entry
  47  */
  48 static int s390_socket_nb_from_ids(int drawer_id, int book_id, int socket_id)
  49 {
  50     return (drawer_id * current_machine->smp.books + book_id) *
  51            current_machine->smp.sockets + socket_id;
  52 }
  53
  54 /**
  55  * s390_socket_nb:
  56  * @cpu: s390x CPU
  57  *
  58  * Returns the socket number used inside the cores_per_socket array
  59  * for a cpu.
  60  */
  61 static int s390_socket_nb(S390CPU *cpu)
  62 {
  63     return s390_socket_nb_from_ids(cpu->env.drawer_id, cpu->env.book_id,
  64                                    cpu->env.socket_id);
  65 }
  66
  67 /**
  68  * s390_has_topology:
  69  *
  70  * Return: true if the topology is supported by the machine.
  71  */
  72 bool s390_has_topology(void)
  73 {
  74     return s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY);
  75 }
  76
  77 /**
  78  * s390_topology_init:
  79  * @ms: the machine state where the machine topology is defined
  80  *
  81  * Keep track of the machine topology.
  82  *
  83  * Allocate an array to keep the count of cores per socket.
  84  * The index of the array starts at socket 0 from book 0 and
  85  * drawer 0 up to the maximum allowed by the machine topology.
  86  */
  87 static void s390_topology_init(MachineState *ms)
  88 {
  89     CpuTopology *smp = &ms->smp;
  90
  91     s390_topology.cores_per_socket = g_new0(uint8_t, smp->sockets *
  92                                             smp->books * smp->drawers);
  93 }
  94
  95 /*
  96  * s390_handle_ptf:
  97  *
  98  * @register 1: contains the function code
  99  *
 100  * Function codes 0 (horizontal) and 1 (vertical) define the CPU
 101  * polarization requested by the guest.
 102  *
 103  * Function code 2 is handling topology changes and is interpreted
 104  * by the SIE.
 105  */
 106 void s390_handle_ptf(S390CPU *cpu, uint8_t r1, uintptr_t ra)
 107 {
 108     CpuS390Polarization polarization;
 109     CPUS390XState *env = &cpu->env;
 110     uint64_t reg = env->regs[r1];
 111     int fc = reg & S390_TOPO_FC_MASK;
 112
 113     if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
 114         s390_program_interrupt(env, PGM_OPERATION, ra);
 115         return;
 116     }
 117
 118     if (env->psw.mask & PSW_MASK_PSTATE) {
 119         s390_program_interrupt(env, PGM_PRIVILEGED, ra);
 120         return;
 121     }
 122
 123     if (reg & ~S390_TOPO_FC_MASK) {
 124         s390_program_interrupt(env, PGM_SPECIFICATION, ra);
 125         return;
 126     }
 127
 128     polarization = S390_CPU_POLARIZATION_VERTICAL;
 129     switch (fc) {
 130     case 0:
 131         polarization = S390_CPU_POLARIZATION_HORIZONTAL;
 132         /* fallthrough */
 133     case 1:
 134         if (s390_topology.polarization == polarization) {
 135             env->regs[r1] |= S390_PTF_REASON_DONE;
 136             setcc(cpu, 2);
 137         } else {
 138             s390_topology.polarization = polarization;
 139             s390_cpu_topology_set_changed(true);
 140             qapi_event_send_cpu_polarization_change(polarization);
 141             setcc(cpu, 0);
 142         }
 143         break;
 144     default:
 145         /* Note that fc == 2 is interpreted by the SIE */
 146         s390_program_interrupt(env, PGM_SPECIFICATION, ra);
 147     }
 148 }
 149
 150 /**
 151  * s390_topology_reset:
 152  *
 153  * Generic reset for CPU topology, calls s390_topology_reset()
 154  * to reset the kernel Modified Topology Change Record.
 155  */
 156 void s390_topology_reset(void)
 157 {
 158     s390_cpu_topology_set_changed(false);
 159     s390_topology.polarization = S390_CPU_POLARIZATION_HORIZONTAL;
 160 }
 161
 162 /**
 163  * s390_topology_cpu_default:
 164  * @cpu: pointer to a S390CPU
 165  * @errp: Error pointer
 166  *
 167  * Setup the default topology if no attributes are already set.
 168  * Passing a CPU with some, but not all, attributes set is considered
 169  * an error.
 170  *
 171  * The function calculates the (drawer_id, book_id, socket_id)
 172  * topology by filling the cores starting from the first socket
 173  * (0, 0, 0) up to the last (smp->drawers, smp->books, smp->sockets).
 174  *
 175  * CPU type and dedication have defaults values set in the
 176  * s390x_cpu_properties, entitlement must be adjust depending on the
 177  * dedication.
 178  *
 179  * Returns false if it is impossible to setup a default topology
 180  * true otherwise.
 181  */
 182 static bool s390_topology_cpu_default(S390CPU *cpu, Error **errp)
 183 {
 184     CpuTopology *smp = &current_machine->smp;
 185     CPUS390XState *env = &cpu->env;
 186
 187     /* All geometry topology attributes must be set or all unset */
 188     if ((env->socket_id < 0 || env->book_id < 0 || env->drawer_id < 0) &&
 189         (env->socket_id >= 0 || env->book_id >= 0 || env->drawer_id >= 0)) {
 190         error_setg(errp,
 191                    "Please define all or none of the topology geometry attributes");
 192         return false;
 193     }
 194
 195     /* If one value is unset all are unset -> calculate defaults */
 196     if (env->socket_id < 0) {
 197         env->socket_id = s390_std_socket(env->core_id, smp);
 198         env->book_id = s390_std_book(env->core_id, smp);
 199         env->drawer_id = s390_std_drawer(env->core_id, smp);
 200     }
 201
 202     /*
 203      * When the user specifies the entitlement as 'auto' on the command line,
 204      * QEMU will set the entitlement as:
 205      * Medium when the CPU is not dedicated.
 206      * High when dedicated is true.
 207      */
 208     if (env->entitlement == S390_CPU_ENTITLEMENT_AUTO) {
 209         if (env->dedicated) {
 210             env->entitlement = S390_CPU_ENTITLEMENT_HIGH;
 211         } else {
 212             env->entitlement = S390_CPU_ENTITLEMENT_MEDIUM;
 213         }
 214     }
 215     return true;
 216 }
 217
 218 /**
 219  * s390_topology_check:
 220  * @socket_id: socket to check
 221  * @book_id: book to check
 222  * @drawer_id: drawer to check
 223  * @entitlement: entitlement to check
 224  * @dedicated: dedication to check
 225  * @errp: Error pointer
 226  *
 227  * The function checks if the topology
 228  * attributes fits inside the system topology.
 229  *
 230  * Returns false if the specified topology does not match with
 231  * the machine topology.
 232  */
 233 static bool s390_topology_check(uint16_t socket_id, uint16_t book_id,
 234                                 uint16_t drawer_id, uint16_t entitlement,
 235                                 bool dedicated, Error **errp)
 236 {
 237     CpuTopology *smp = &current_machine->smp;
 238
 239     if (socket_id >= smp->sockets) {
 240         error_setg(errp, "Unavailable socket: %d", socket_id);
 241         return false;
 242     }
 243     if (book_id >= smp->books) {
 244         error_setg(errp, "Unavailable book: %d", book_id);
 245         return false;
 246     }
 247     if (drawer_id >= smp->drawers) {
 248         error_setg(errp, "Unavailable drawer: %d", drawer_id);
 249         return false;
 250     }
 251     if (entitlement >= S390_CPU_ENTITLEMENT__MAX) {
 252         error_setg(errp, "Unknown entitlement: %d", entitlement);
 253         return false;
 254     }
 255     if (dedicated && (entitlement == S390_CPU_ENTITLEMENT_LOW ||
 256                       entitlement == S390_CPU_ENTITLEMENT_MEDIUM)) {
 257         error_setg(errp, "A dedicated CPU implies high entitlement");
 258         return false;
 259     }
 260     return true;
 261 }
 262
 263 /**
 264  * s390_topology_need_report
 265  * @cpu: Current cpu
 266  * @drawer_id: future drawer ID
 267  * @book_id: future book ID
 268  * @socket_id: future socket ID
 269  * @entitlement: future entitlement
 270  * @dedicated: future dedicated
 271  *
 272  * A modified topology change report is needed if the topology
 273  * tree or the topology attributes change.
 274  */
 275 static bool s390_topology_need_report(S390CPU *cpu, int drawer_id,
 276                                       int book_id, int socket_id,
 277                                       uint16_t entitlement, bool dedicated)
 278 {
 279     return cpu->env.drawer_id != drawer_id ||
 280            cpu->env.book_id != book_id ||
 281            cpu->env.socket_id != socket_id ||
 282            cpu->env.entitlement != entitlement ||
 283            cpu->env.dedicated != dedicated;
 284 }
 285
 286 /**
 287  * s390_update_cpu_props:
 288  * @ms: the machine state
 289  * @cpu: the CPU for which to update the properties from the environment.
 290  *
 291  */
 292 static void s390_update_cpu_props(MachineState *ms, S390CPU *cpu)
 293 {
 294     CpuInstanceProperties *props;
 295
 296     props = &ms->possible_cpus->cpus[cpu->env.core_id].props;
 297
 298     props->socket_id = cpu->env.socket_id;
 299     props->book_id = cpu->env.book_id;
 300     props->drawer_id = cpu->env.drawer_id;
 301 }
 302
 303 /**
 304  * s390_topology_setup_cpu:
 305  * @ms: MachineState used to initialize the topology structure on
 306  *      first call.
 307  * @cpu: the new S390CPU to insert in the topology structure
 308  * @errp: the error pointer
 309  *
 310  * Called from CPU hotplug to check and setup the CPU attributes
 311  * before the CPU is inserted in the topology.
 312  * There is no need to update the MTCR explicitly here because it
 313  * will be updated by KVM on creation of the new CPU.
 314  */
 315 void s390_topology_setup_cpu(MachineState *ms, S390CPU *cpu, Error **errp)
 316 {
 317     int entry;
 318
 319     /*
 320      * We do not want to initialize the topology if the CPU model
 321      * does not support topology, consequently, we have to wait for
 322      * the first CPU to be realized, which realizes the CPU model
 323      * to initialize the topology structures.
 324      *
 325      * s390_topology_setup_cpu() is called from the CPU hotplug.
 326      */
 327     if (!s390_topology.cores_per_socket) {
 328         s390_topology_init(ms);
 329     }
 330
 331     if (!s390_topology_cpu_default(cpu, errp)) {
 332         return;
 333     }
 334
 335     if (!s390_topology_check(cpu->env.socket_id, cpu->env.book_id,
 336                              cpu->env.drawer_id, cpu->env.entitlement,
 337                              cpu->env.dedicated, errp)) {
 338         return;
 339     }
 340
 341     /* Do we still have space in the socket */
 342     entry = s390_socket_nb(cpu);
 343     if (s390_topology.cores_per_socket[entry] >= ms->smp.cores) {
 344         error_setg(errp, "No more space on this socket");
 345         return;
 346     }
 347
 348     /* Update the count of cores in sockets */
 349     s390_topology.cores_per_socket[entry] += 1;
 350
 351     /* topology tree is reflected in props */
 352     s390_update_cpu_props(ms, cpu);
 353 }
 354
 355 static void s390_change_topology(uint16_t core_id,
 356                                  bool has_socket_id, uint16_t socket_id,
 357                                  bool has_book_id, uint16_t book_id,
 358                                  bool has_drawer_id, uint16_t drawer_id,
 359                                  bool has_entitlement,
 360                                  CpuS390Entitlement entitlement,
 361                                  bool has_dedicated, bool dedicated,
 362                                  Error **errp)
 363 {
 364     MachineState *ms = current_machine;
 365     int old_socket_entry;
 366     int new_socket_entry;
 367     bool report_needed;
 368     S390CPU *cpu;
 369
 370     cpu = s390_cpu_addr2state(core_id);
 371     if (!cpu) {
 372         error_setg(errp, "Core-id %d does not exist!", core_id);
 373         return;
 374     }
 375
 376     /* Get attributes not provided from cpu and verify the new topology */
 377     if (!has_socket_id) {
 378         socket_id = cpu->env.socket_id;
 379     }
 380     if (!has_book_id) {
 381         book_id = cpu->env.book_id;
 382     }
 383     if (!has_drawer_id) {
 384         drawer_id = cpu->env.drawer_id;
 385     }
 386     if (!has_dedicated) {
 387         dedicated = cpu->env.dedicated;
 388     }
 389
 390     /*
 391      * When the user specifies the entitlement as 'auto' on the command line,
 392      * QEMU will set the entitlement as:
 393      * Medium when the CPU is not dedicated.
 394      * High when dedicated is true.
 395      */
 396     if (!has_entitlement || entitlement == S390_CPU_ENTITLEMENT_AUTO) {
 397         if (dedicated) {
 398             entitlement = S390_CPU_ENTITLEMENT_HIGH;
 399         } else {
 400             entitlement = S390_CPU_ENTITLEMENT_MEDIUM;
 401         }
 402     }
 403
 404     if (!s390_topology_check(socket_id, book_id, drawer_id,
 405                              entitlement, dedicated, errp)) {
 406         return;
 407     }
 408
 409     /* Check for space on new socket */
 410     old_socket_entry = s390_socket_nb(cpu);
 411     new_socket_entry = s390_socket_nb_from_ids(drawer_id, book_id, socket_id);
 412
 413     if (new_socket_entry != old_socket_entry) {
 414         if (s390_topology.cores_per_socket[new_socket_entry] >=
 415             ms->smp.cores) {
 416             error_setg(errp, "No more space on this socket");
 417             return;
 418         }
 419         /* Update the count of cores in sockets */
 420         s390_topology.cores_per_socket[new_socket_entry] += 1;
 421         s390_topology.cores_per_socket[old_socket_entry] -= 1;
 422     }
 423
 424     /* Check if we will need to report the modified topology */
 425     report_needed = s390_topology_need_report(cpu, drawer_id, book_id,
 426                                               socket_id, entitlement,
 427                                               dedicated);
 428
 429     /* All checks done, report new topology into the vCPU */
 430     cpu->env.drawer_id = drawer_id;
 431     cpu->env.book_id = book_id;
 432     cpu->env.socket_id = socket_id;
 433     cpu->env.dedicated = dedicated;
 434     cpu->env.entitlement = entitlement;
 435
 436     /* topology tree is reflected in props */
 437     s390_update_cpu_props(ms, cpu);
 438
 439     /* Advertise the topology change */
 440     if (report_needed) {
 441         s390_cpu_topology_set_changed(true);
 442     }
 443 }
 444
 445 void qmp_set_cpu_topology(uint16_t core,
 446                           bool has_socket, uint16_t socket,
 447                           bool has_book, uint16_t book,
 448                           bool has_drawer, uint16_t drawer,
 449                           bool has_entitlement, CpuS390Entitlement entitlement,
 450                           bool has_dedicated, bool dedicated,
 451                           Error **errp)
 452 {
 453     if (!s390_has_topology()) {
 454         error_setg(errp, "This machine doesn't support topology");
 455         return;
 456     }
 457
 458     s390_change_topology(core, has_socket, socket, has_book, book,
 459                          has_drawer, drawer, has_entitlement, entitlement,
 460                          has_dedicated, dedicated, errp);
 461 }
 462
 463 CpuPolarizationInfo *qmp_query_s390x_cpu_polarization(Error **errp)
 464 {
 465     CpuPolarizationInfo *info = g_new0(CpuPolarizationInfo, 1);
 466
 467     info->polarization = s390_topology.polarization;
 468     return info;
 469 }