include/hw/i386/topology.h

   1 /*
   2  *  x86 CPU topology data structures and functions
   3  *
   4  *  Copyright (c) 2012 Red Hat Inc.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #ifndef HW_I386_TOPOLOGY_H
  25 #define HW_I386_TOPOLOGY_H
  26
  27 /* This file implements the APIC-ID-based CPU topology enumeration logic,
  28  * documented at the following document:
  29  *   Intel® 64 Architecture Processor Topology Enumeration
  30  *   http://software.intel.com/en-us/articles/intel-64-architecture-processor-topology-enumeration/
  31  *
  32  * This code should be compatible with AMD's "Extended Method" described at:
  33  *   AMD CPUID Specification (Publication #25481)
  34  *   Section 3: Multiple Core Calcuation
  35  * as long as:
  36  *  nr_threads is set to 1;
  37  *  OFFSET_IDX is assumed to be 0;
  38  *  CPUID Fn8000_0008_ECX[ApicIdCoreIdSize[3:0]] is set to apicid_core_width().
  39  */
  40
  41
  42 #include "qemu/bitops.h"
  43
  44 /* APIC IDs can be 32-bit, but beware: APIC IDs > 255 require x2APIC support
  45  */
  46 typedef uint32_t apic_id_t;
  47
  48 typedef struct X86CPUTopoIDs {
  49     unsigned pkg_id;
  50     unsigned die_id;
  51     unsigned core_id;
  52     unsigned smt_id;
  53 } X86CPUTopoIDs;
  54
  55 typedef struct X86CPUTopoInfo {
  56     unsigned dies_per_pkg;
  57     unsigned cores_per_die;
  58     unsigned threads_per_core;
  59 } X86CPUTopoInfo;
  60
  61 /* Return the bit width needed for 'count' IDs
  62  */
  63 static unsigned apicid_bitwidth_for_count(unsigned count)
  64 {
  65     g_assert(count >= 1);
  66     count -= 1;
  67     return count ? 32 - clz32(count) : 0;
  68 }
  69
  70 /* Bit width of the SMT_ID (thread ID) field on the APIC ID
  71  */
  72 static inline unsigned apicid_smt_width(X86CPUTopoInfo *topo_info)
  73 {
  74     return apicid_bitwidth_for_count(topo_info->threads_per_core);
  75 }
  76
  77 /* Bit width of the Core_ID field
  78  */
  79 static inline unsigned apicid_core_width(X86CPUTopoInfo *topo_info)
  80 {
  81     return apicid_bitwidth_for_count(topo_info->cores_per_die);
  82 }
  83
  84 /* Bit width of the Die_ID field */
  85 static inline unsigned apicid_die_width(X86CPUTopoInfo *topo_info)
  86 {
  87     return apicid_bitwidth_for_count(topo_info->dies_per_pkg);
  88 }
  89
  90 /* Bit offset of the Core_ID field
  91  */
  92 static inline unsigned apicid_core_offset(X86CPUTopoInfo *topo_info)
  93 {
  94     return apicid_smt_width(topo_info);
  95 }
  96
  97 /* Bit offset of the Die_ID field */
  98 static inline unsigned apicid_die_offset(X86CPUTopoInfo *topo_info)
  99 {
 100     return apicid_core_offset(topo_info) + apicid_core_width(topo_info);
 101 }
 102
 103 /* Bit offset of the Pkg_ID (socket ID) field
 104  */
 105 static inline unsigned apicid_pkg_offset(X86CPUTopoInfo *topo_info)
 106 {
 107     return apicid_die_offset(topo_info) + apicid_die_width(topo_info);
 108 }
 109
 110 /* Make APIC ID for the CPU based on Pkg_ID, Core_ID, SMT_ID
 111  *
 112  * The caller must make sure core_id < nr_cores and smt_id < nr_threads.
 113  */
 114 static inline apic_id_t x86_apicid_from_topo_ids(X86CPUTopoInfo *topo_info,
 115                                                  const X86CPUTopoIDs *topo_ids)
 116 {
 117     return (topo_ids->pkg_id  << apicid_pkg_offset(topo_info)) |
 118            (topo_ids->die_id  << apicid_die_offset(topo_info)) |
 119            (topo_ids->core_id << apicid_core_offset(topo_info)) |
 120            topo_ids->smt_id;
 121 }
 122
 123 /* Calculate thread/core/package IDs for a specific topology,
 124  * based on (contiguous) CPU index
 125  */
 126 static inline void x86_topo_ids_from_idx(X86CPUTopoInfo *topo_info,
 127                                          unsigned cpu_index,
 128                                          X86CPUTopoIDs *topo_ids)
 129 {
 130     unsigned nr_dies = topo_info->dies_per_pkg;
 131     unsigned nr_cores = topo_info->cores_per_die;
 132     unsigned nr_threads = topo_info->threads_per_core;
 133
 134     topo_ids->pkg_id = cpu_index / (nr_dies * nr_cores * nr_threads);
 135     topo_ids->die_id = cpu_index / (nr_cores * nr_threads) % nr_dies;
 136     topo_ids->core_id = cpu_index / nr_threads % nr_cores;
 137     topo_ids->smt_id = cpu_index % nr_threads;
 138 }
 139
 140 /* Calculate thread/core/package IDs for a specific topology,
 141  * based on APIC ID
 142  */
 143 static inline void x86_topo_ids_from_apicid(apic_id_t apicid,
 144                                             X86CPUTopoInfo *topo_info,
 145                                             X86CPUTopoIDs *topo_ids)
 146 {
 147     topo_ids->smt_id = apicid &
 148             ~(0xFFFFFFFFUL << apicid_smt_width(topo_info));
 149     topo_ids->core_id =
 150             (apicid >> apicid_core_offset(topo_info)) &
 151             ~(0xFFFFFFFFUL << apicid_core_width(topo_info));
 152     topo_ids->die_id =
 153             (apicid >> apicid_die_offset(topo_info)) &
 154             ~(0xFFFFFFFFUL << apicid_die_width(topo_info));
 155     topo_ids->pkg_id = apicid >> apicid_pkg_offset(topo_info);
 156 }
 157
 158 /* Make APIC ID for the CPU 'cpu_index'
 159  *
 160  * 'cpu_index' is a sequential, contiguous ID for the CPU.
 161  */
 162 static inline apic_id_t x86_apicid_from_cpu_idx(X86CPUTopoInfo *topo_info,
 163                                                 unsigned cpu_index)
 164 {
 165     X86CPUTopoIDs topo_ids;
 166     x86_topo_ids_from_idx(topo_info, cpu_index, &topo_ids);
 167     return x86_apicid_from_topo_ids(topo_info, &topo_ids);
 168 }
 169
 170 #endif /* HW_I386_TOPOLOGY_H */