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 #include <stdint.h> 42 #include <string.h> 43 44 #include "qemu/bitops.h" 45 46 /* APIC IDs can be 32-bit, but beware: APIC IDs > 255 require x2APIC support 47 */ 48 typedef uint32_t apic_id_t; 49 50 typedef struct X86CPUTopoInfo { 51 unsigned pkg_id; 52 unsigned core_id; 53 unsigned smt_id; 54 } X86CPUTopoInfo; 55 56 /* Return the bit width needed for 'count' IDs 57 */ 58 static unsigned apicid_bitwidth_for_count(unsigned count) 59 { 60 g_assert(count >= 1); 61 count -= 1; 62 return count ? 32 - clz32(count) : 0; 63 } 64 65 /* Bit width of the SMT_ID (thread ID) field on the APIC ID 66 */ 67 static inline unsigned apicid_smt_width(unsigned nr_cores, unsigned nr_threads) 68 { 69 return apicid_bitwidth_for_count(nr_threads); 70 } 71 72 /* Bit width of the Core_ID field 73 */ 74 static inline unsigned apicid_core_width(unsigned nr_cores, unsigned nr_threads) 75 { 76 return apicid_bitwidth_for_count(nr_cores); 77 } 78 79 /* Bit offset of the Core_ID field 80 */ 81 static inline unsigned apicid_core_offset(unsigned nr_cores, 82 unsigned nr_threads) 83 { 84 return apicid_smt_width(nr_cores, nr_threads); 85 } 86 87 /* Bit offset of the Pkg_ID (socket ID) field 88 */ 89 static inline unsigned apicid_pkg_offset(unsigned nr_cores, unsigned nr_threads) 90 { 91 return apicid_core_offset(nr_cores, nr_threads) + 92 apicid_core_width(nr_cores, nr_threads); 93 } 94 95 /* Make APIC ID for the CPU based on Pkg_ID, Core_ID, SMT_ID 96 * 97 * The caller must make sure core_id < nr_cores and smt_id < nr_threads. 98 */ 99 static inline apic_id_t apicid_from_topo_ids(unsigned nr_cores, 100 unsigned nr_threads, 101 const X86CPUTopoInfo *topo) 102 { 103 return (topo->pkg_id << apicid_pkg_offset(nr_cores, nr_threads)) | 104 (topo->core_id << apicid_core_offset(nr_cores, nr_threads)) | 105 topo->smt_id; 106 } 107 108 /* Calculate thread/core/package IDs for a specific topology, 109 * based on (contiguous) CPU index 110 */ 111 static inline void x86_topo_ids_from_idx(unsigned nr_cores, 112 unsigned nr_threads, 113 unsigned cpu_index, 114 X86CPUTopoInfo *topo) 115 { 116 unsigned core_index = cpu_index / nr_threads; 117 topo->smt_id = cpu_index % nr_threads; 118 topo->core_id = core_index % nr_cores; 119 topo->pkg_id = core_index / nr_cores; 120 } 121 122 /* Make APIC ID for the CPU 'cpu_index' 123 * 124 * 'cpu_index' is a sequential, contiguous ID for the CPU. 125 */ 126 static inline apic_id_t x86_apicid_from_cpu_idx(unsigned nr_cores, 127 unsigned nr_threads, 128 unsigned cpu_index) 129 { 130 X86CPUTopoInfo topo; 131 x86_topo_ids_from_idx(nr_cores, nr_threads, cpu_index, &topo); 132 return apicid_from_topo_ids(nr_cores, nr_threads, &topo); 133 } 134 135 #endif /* HW_I386_TOPOLOGY_H */ 136