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/*
* 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 HW_I386_TOPOLOGY_H
#define HW_I386_TOPOLOGY_H
/* This file implements the APIC-ID-based CPU topology enumeration logic,
* documented at the following document:
* Intel® 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;
typedef struct X86CPUTopoInfo {
unsigned pkg_id;
unsigned core_id;
unsigned smt_id;
} X86CPUTopoInfo;
/* Return the bit width needed for 'count' IDs
*/
static unsigned apicid_bitwidth_for_count(unsigned count)
{
g_assert(count >= 1);
count -= 1;
return count ? 32 - clz32(count) : 0;
}
/* 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,
const X86CPUTopoInfo *topo)
{
return (topo->pkg_id << apicid_pkg_offset(nr_cores, nr_threads)) |
(topo->core_id << apicid_core_offset(nr_cores, nr_threads)) |
topo->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,
X86CPUTopoInfo *topo)
{
unsigned core_index = cpu_index / nr_threads;
topo->smt_id = cpu_index % nr_threads;
topo->core_id = core_index % nr_cores;
topo->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)
{
X86CPUTopoInfo topo;
x86_topo_ids_from_idx(nr_cores, nr_threads, cpu_index, &topo);
return apicid_from_topo_ids(nr_cores, nr_threads, &topo);
}
#endif /* HW_I386_TOPOLOGY_H */
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