aboutsummaryrefslogtreecommitdiff
path: root/target-i386/topology.h
blob: 24ed525453ed3c94242c44a17e9b660f66f58051 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/*
 *  x86 CPU topology data structures and functions
 *
 *  Copyright (c) 2012 Red Hat Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#ifndef TARGET_I386_TOPOLOGY_H
#define TARGET_I386_TOPOLOGY_H

/* This file implements the APIC-ID-based CPU topology enumeration logic,
 * documented at the following document:
 *   IntelĀ® 64 Architecture Processor Topology Enumeration
 *   http://software.intel.com/en-us/articles/intel-64-architecture-processor-topology-enumeration/
 *
 * This code should be compatible with AMD's "Extended Method" described at:
 *   AMD CPUID Specification (Publication #25481)
 *   Section 3: Multiple Core Calcuation
 * as long as:
 *  nr_threads is set to 1;
 *  OFFSET_IDX is assumed to be 0;
 *  CPUID Fn8000_0008_ECX[ApicIdCoreIdSize[3:0]] is set to apicid_core_width().
 */

#include <stdint.h>
#include <string.h>

#include "qemu/bitops.h"

/* APIC IDs can be 32-bit, but beware: APIC IDs > 255 require x2APIC support
 */
typedef uint32_t apic_id_t;

/* Return the bit width needed for 'count' IDs
 */
static unsigned apicid_bitwidth_for_count(unsigned count)
{
    g_assert(count >= 1);
    if (count == 1) {
        return 0;
    }
    return bitops_flsl(count - 1) + 1;
}

/* Bit width of the SMT_ID (thread ID) field on the APIC ID
 */
static inline unsigned apicid_smt_width(unsigned nr_cores, unsigned nr_threads)
{
    return apicid_bitwidth_for_count(nr_threads);
}

/* Bit width of the Core_ID field
 */
static inline unsigned apicid_core_width(unsigned nr_cores, unsigned nr_threads)
{
    return apicid_bitwidth_for_count(nr_cores);
}

/* Bit offset of the Core_ID field
 */
static inline unsigned apicid_core_offset(unsigned nr_cores,
                                          unsigned nr_threads)
{
    return apicid_smt_width(nr_cores, nr_threads);
}

/* Bit offset of the Pkg_ID (socket ID) field
 */
static inline unsigned apicid_pkg_offset(unsigned nr_cores, unsigned nr_threads)
{
    return apicid_core_offset(nr_cores, nr_threads) +
           apicid_core_width(nr_cores, nr_threads);
}

/* Make APIC ID for the CPU based on Pkg_ID, Core_ID, SMT_ID
 *
 * The caller must make sure core_id < nr_cores and smt_id < nr_threads.
 */
static inline apic_id_t apicid_from_topo_ids(unsigned nr_cores,
                                             unsigned nr_threads,
                                             unsigned pkg_id,
                                             unsigned core_id,
                                             unsigned smt_id)
{
    return (pkg_id  << apicid_pkg_offset(nr_cores, nr_threads)) |
           (core_id << apicid_core_offset(nr_cores, nr_threads)) |
           smt_id;
}

/* Calculate thread/core/package IDs for a specific topology,
 * based on (contiguous) CPU index
 */
static inline void x86_topo_ids_from_idx(unsigned nr_cores,
                                         unsigned nr_threads,
                                         unsigned cpu_index,
                                         unsigned *pkg_id,
                                         unsigned *core_id,
                                         unsigned *smt_id)
{
    unsigned core_index = cpu_index / nr_threads;
    *smt_id = cpu_index % nr_threads;
    *core_id = core_index % nr_cores;
    *pkg_id = core_index / nr_cores;
}

/* Make APIC ID for the CPU 'cpu_index'
 *
 * 'cpu_index' is a sequential, contiguous ID for the CPU.
 */
static inline apic_id_t x86_apicid_from_cpu_idx(unsigned nr_cores,
                                                unsigned nr_threads,
                                                unsigned cpu_index)
{
    unsigned pkg_id, core_id, smt_id;
    x86_topo_ids_from_idx(nr_cores, nr_threads, cpu_index,
                          &pkg_id, &core_id, &smt_id);
    return apicid_from_topo_ids(nr_cores, nr_threads, pkg_id, core_id, smt_id);
}

#endif /* TARGET_I386_TOPOLOGY_H */