target/i386/host-cpu.c

   1 /*
   2  * x86 host CPU functions, and "host" cpu type initialization
   3  *
   4  * Copyright 2021 SUSE LLC
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  */
   9
  10 #include "qemu/osdep.h"
  11 #include "cpu.h"
  12 #include "host-cpu.h"
  13 #include "qapi/error.h"
  14 #include "qemu/error-report.h"
  15 #include "sysemu/sysemu.h"
  16
  17 /* Note: Only safe for use on x86(-64) hosts */
  18 static uint32_t host_cpu_phys_bits(void)
  19 {
  20     uint32_t eax;
  21     uint32_t host_phys_bits;
  22
  23     host_cpuid(0x80000000, 0, &eax, NULL, NULL, NULL);
  24     if (eax >= 0x80000008) {
  25         host_cpuid(0x80000008, 0, &eax, NULL, NULL, NULL);
  26         /*
  27          * Note: According to AMD doc 25481 rev 2.34 they have a field
  28          * at 23:16 that can specify a maximum physical address bits for
  29          * the guest that can override this value; but I've not seen
  30          * anything with that set.
  31          */
  32         host_phys_bits = eax & 0xff;
  33     } else {
  34         /*
  35          * It's an odd 64 bit machine that doesn't have the leaf for
  36          * physical address bits; fall back to 36 that's most older
  37          * Intel.
  38          */
  39         host_phys_bits = 36;
  40     }
  41
  42     return host_phys_bits;
  43 }
  44
  45 static uint32_t host_cpu_adjust_phys_bits(X86CPU *cpu)
  46 {
  47     uint32_t host_phys_bits = host_cpu_phys_bits();
  48     uint32_t phys_bits = cpu->phys_bits;
  49
  50     /*
  51      * Print a warning if the user set it to a value that's not the
  52      * host value.
  53      */
  54     if (phys_bits != host_phys_bits && phys_bits != 0) {
  55         warn_report_once("Host physical bits (%u)"
  56                          " does not match phys-bits property (%u)",
  57                          host_phys_bits, phys_bits);
  58     }
  59
  60     if (cpu->host_phys_bits) {
  61         /* The user asked for us to use the host physical bits */
  62         phys_bits = host_phys_bits;
  63         if (cpu->host_phys_bits_limit &&
  64             phys_bits > cpu->host_phys_bits_limit) {
  65             phys_bits = cpu->host_phys_bits_limit;
  66         }
  67     }
  68
  69     return phys_bits;
  70 }
  71
  72 bool host_cpu_realizefn(CPUState *cs, Error **errp)
  73 {
  74     X86CPU *cpu = X86_CPU(cs);
  75     CPUX86State *env = &cpu->env;
  76
  77     if (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM) {
  78         uint32_t phys_bits = host_cpu_adjust_phys_bits(cpu);
  79
  80         if (phys_bits &&
  81             (phys_bits > TARGET_PHYS_ADDR_SPACE_BITS ||
  82              phys_bits < 32)) {
  83             error_setg(errp, "phys-bits should be between 32 and %u "
  84                        " (but is %u)",
  85                        TARGET_PHYS_ADDR_SPACE_BITS, phys_bits);
  86             return false;
  87         }
  88         cpu->phys_bits = phys_bits;
  89     }
  90     return true;
  91 }
  92
  93 #define CPUID_MODEL_ID_SZ 48
  94 /**
  95  * cpu_x86_fill_model_id:
  96  * Get CPUID model ID string from host CPU.
  97  *
  98  * @str should have at least CPUID_MODEL_ID_SZ bytes
  99  *
 100  * The function does NOT add a null terminator to the string
 101  * automatically.
 102  */
 103 static int host_cpu_fill_model_id(char *str)
 104 {
 105     uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
 106     int i;
 107
 108     for (i = 0; i < 3; i++) {
 109         host_cpuid(0x80000002 + i, 0, &eax, &ebx, &ecx, &edx);
 110         memcpy(str + i * 16 +  0, &eax, 4);
 111         memcpy(str + i * 16 +  4, &ebx, 4);
 112         memcpy(str + i * 16 +  8, &ecx, 4);
 113         memcpy(str + i * 16 + 12, &edx, 4);
 114     }
 115     return 0;
 116 }
 117
 118 void host_cpu_vendor_fms(char *vendor, int *family, int *model, int *stepping)
 119 {
 120     uint32_t eax, ebx, ecx, edx;
 121
 122     host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
 123     x86_cpu_vendor_words2str(vendor, ebx, edx, ecx);
 124
 125     host_cpuid(0x1, 0, &eax, &ebx, &ecx, &edx);
 126     if (family) {
 127         *family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
 128     }
 129     if (model) {
 130         *model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
 131     }
 132     if (stepping) {
 133         *stepping = eax & 0x0F;
 134     }
 135 }
 136
 137 void host_cpu_instance_init(X86CPU *cpu)
 138 {
 139     X86CPUClass *xcc = X86_CPU_GET_CLASS(cpu);
 140
 141     if (xcc->model) {
 142         uint32_t ebx = 0, ecx = 0, edx = 0;
 143         char vendor[CPUID_VENDOR_SZ + 1];
 144
 145         host_cpuid(0, 0, NULL, &ebx, &ecx, &edx);
 146         x86_cpu_vendor_words2str(vendor, ebx, edx, ecx);
 147         object_property_set_str(OBJECT(cpu), "vendor", vendor, &error_abort);
 148     }
 149 }
 150
 151 void host_cpu_max_instance_init(X86CPU *cpu)
 152 {
 153     char vendor[CPUID_VENDOR_SZ + 1] = { 0 };
 154     char model_id[CPUID_MODEL_ID_SZ + 1] = { 0 };
 155     int family, model, stepping;
 156
 157     /* Use max host physical address bits if -cpu max option is applied */
 158     object_property_set_bool(OBJECT(cpu), "host-phys-bits", true, &error_abort);
 159
 160     host_cpu_vendor_fms(vendor, &family, &model, &stepping);
 161     host_cpu_fill_model_id(model_id);
 162
 163     object_property_set_str(OBJECT(cpu), "vendor", vendor, &error_abort);
 164     object_property_set_int(OBJECT(cpu), "family", family, &error_abort);
 165     object_property_set_int(OBJECT(cpu), "model", model, &error_abort);
 166     object_property_set_int(OBJECT(cpu), "stepping", stepping,
 167                             &error_abort);
 168     object_property_set_str(OBJECT(cpu), "model-id", model_id,
 169                             &error_abort);
 170 }
 171
 172 static void host_cpu_class_init(ObjectClass *oc, void *data)
 173 {
 174     X86CPUClass *xcc = X86_CPU_CLASS(oc);
 175
 176     xcc->host_cpuid_required = true;
 177     xcc->ordering = 8;
 178     xcc->model_description =
 179         g_strdup_printf("processor with all supported host features ");
 180 }
 181
 182 static const TypeInfo host_cpu_type_info = {
 183     .name = X86_CPU_TYPE_NAME("host"),
 184     .parent = X86_CPU_TYPE_NAME("max"),
 185     .class_init = host_cpu_class_init,
 186 };
 187
 188 static void host_cpu_type_init(void)
 189 {
 190     type_register_static(&host_cpu_type_info);
 191 }
 192
 193 type_init(host_cpu_type_init);