target/i386/kvm/kvm-cpu.c

   1 /*
   2  * x86 KVM 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 "kvm-cpu.h"
  14 #include "qapi/error.h"
  15 #include "sysemu/sysemu.h"
  16 #include "hw/boards.h"
  17
  18 #include "kvm_i386.h"
  19 #include "hw/core/accel-cpu.h"
  20
  21 static bool kvm_cpu_realizefn(CPUState *cs, Error **errp)
  22 {
  23     X86CPU *cpu = X86_CPU(cs);
  24     CPUX86State *env = &cpu->env;
  25
  26     /*
  27      * The realize order is important, since x86_cpu_realize() checks if
  28      * nothing else has been set by the user (or by accelerators) in
  29      * cpu->ucode_rev and cpu->phys_bits, and updates the CPUID results in
  30      * mwait.ecx.
  31      * This accel realization code also assumes cpu features are already expanded.
  32      *
  33      * realize order:
  34      *
  35      * x86_cpu_realize():
  36      *  -> x86_cpu_expand_features()
  37      *  -> cpu_exec_realizefn():
  38      *            -> accel_cpu_realize()
  39      *               kvm_cpu_realizefn() -> host_cpu_realizefn()
  40      *  -> check/update ucode_rev, phys_bits, mwait
  41      */
  42     if (cpu->max_features) {
  43         if (enable_cpu_pm && kvm_has_waitpkg()) {
  44             env->features[FEAT_7_0_ECX] |= CPUID_7_0_ECX_WAITPKG;
  45         }
  46         if (cpu->ucode_rev == 0) {
  47             cpu->ucode_rev =
  48                 kvm_arch_get_supported_msr_feature(kvm_state,
  49                                                    MSR_IA32_UCODE_REV);
  50         }
  51     }
  52     return host_cpu_realizefn(cs, errp);
  53 }
  54
  55 static bool lmce_supported(void)
  56 {
  57     uint64_t mce_cap = 0;
  58
  59     if (kvm_ioctl(kvm_state, KVM_X86_GET_MCE_CAP_SUPPORTED, &mce_cap) < 0) {
  60         return false;
  61     }
  62     return !!(mce_cap & MCG_LMCE_P);
  63 }
  64
  65 static void kvm_cpu_max_instance_init(X86CPU *cpu)
  66 {
  67     CPUX86State *env = &cpu->env;
  68     KVMState *s = kvm_state;
  69
  70     host_cpu_max_instance_init(cpu);
  71
  72     if (lmce_supported()) {
  73         object_property_set_bool(OBJECT(cpu), "lmce", true, &error_abort);
  74     }
  75
  76     env->cpuid_min_level =
  77         kvm_arch_get_supported_cpuid(s, 0x0, 0, R_EAX);
  78     env->cpuid_min_xlevel =
  79         kvm_arch_get_supported_cpuid(s, 0x80000000, 0, R_EAX);
  80     env->cpuid_min_xlevel2 =
  81         kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX);
  82 }
  83
  84 static void kvm_cpu_xsave_init(void)
  85 {
  86     static bool first = true;
  87     uint32_t eax, ebx, ecx, edx;
  88     int i;
  89
  90     if (!first) {
  91         return;
  92     }
  93     first = false;
  94
  95     /* x87 and SSE states are in the legacy region of the XSAVE area. */
  96     x86_ext_save_areas[XSTATE_FP_BIT].offset = 0;
  97     x86_ext_save_areas[XSTATE_SSE_BIT].offset = 0;
  98
  99     for (i = XSTATE_SSE_BIT + 1; i < XSAVE_STATE_AREA_COUNT; i++) {
 100         ExtSaveArea *esa = &x86_ext_save_areas[i];
 101
 102         if (!esa->size) {
 103             continue;
 104         }
 105         if ((x86_cpu_get_supported_feature_word(esa->feature, false) & esa->bits)
 106             != esa->bits) {
 107             continue;
 108         }
 109         host_cpuid(0xd, i, &eax, &ebx, &ecx, &edx);
 110         if (eax != 0) {
 111             assert(esa->size == eax);
 112             esa->offset = ebx;
 113             esa->ecx = ecx;
 114         }
 115     }
 116 }
 117
 118 /*
 119  * KVM-specific features that are automatically added/removed
 120  * from cpudef models when KVM is enabled.
 121  * Only for builtin_x86_defs models initialized with x86_register_cpudef_types.
 122  *
 123  * NOTE: features can be enabled by default only if they were
 124  *       already available in the oldest kernel version supported
 125  *       by the KVM accelerator (see "OS requirements" section at
 126  *       docs/system/target-i386.rst)
 127  */
 128 static PropValue kvm_default_props[] = {
 129     { "kvmclock", "on" },
 130     { "kvm-nopiodelay", "on" },
 131     { "kvm-asyncpf", "on" },
 132     { "kvm-steal-time", "on" },
 133     { "kvm-pv-eoi", "on" },
 134     { "kvmclock-stable-bit", "on" },
 135     { "x2apic", "on" },
 136     { "kvm-msi-ext-dest-id", "off" },
 137     { "acpi", "off" },
 138     { "monitor", "off" },
 139     { "svm", "off" },
 140     { NULL, NULL },
 141 };
 142
 143 /*
 144  * Only for builtin_x86_defs models initialized with x86_register_cpudef_types.
 145  */
 146 void x86_cpu_change_kvm_default(const char *prop, const char *value)
 147 {
 148     PropValue *pv;
 149     for (pv = kvm_default_props; pv->prop; pv++) {
 150         if (!strcmp(pv->prop, prop)) {
 151             pv->value = value;
 152             break;
 153         }
 154     }
 155
 156     /*
 157      * It is valid to call this function only for properties that
 158      * are already present in the kvm_default_props table.
 159      */
 160     assert(pv->prop);
 161 }
 162
 163 static void kvm_cpu_instance_init(CPUState *cs)
 164 {
 165     X86CPU *cpu = X86_CPU(cs);
 166     X86CPUClass *xcc = X86_CPU_GET_CLASS(cpu);
 167
 168     host_cpu_instance_init(cpu);
 169
 170     if (xcc->model) {
 171         /* only applies to builtin_x86_defs cpus */
 172         if (!kvm_irqchip_in_kernel()) {
 173             x86_cpu_change_kvm_default("x2apic", "off");
 174         } else if (kvm_irqchip_is_split()) {
 175             x86_cpu_change_kvm_default("kvm-msi-ext-dest-id", "on");
 176         }
 177
 178         /* Special cases not set in the X86CPUDefinition structs: */
 179         x86_cpu_apply_props(cpu, kvm_default_props);
 180     }
 181
 182     if (cpu->max_features) {
 183         kvm_cpu_max_instance_init(cpu);
 184     }
 185
 186     kvm_cpu_xsave_init();
 187 }
 188
 189 static void kvm_cpu_accel_class_init(ObjectClass *oc, void *data)
 190 {
 191     AccelCPUClass *acc = ACCEL_CPU_CLASS(oc);
 192
 193     acc->cpu_target_realize = kvm_cpu_realizefn;
 194     acc->cpu_instance_init = kvm_cpu_instance_init;
 195 }
 196 static const TypeInfo kvm_cpu_accel_type_info = {
 197     .name = ACCEL_CPU_NAME("kvm"),
 198
 199     .parent = TYPE_ACCEL_CPU,
 200     .class_init = kvm_cpu_accel_class_init,
 201     .abstract = true,
 202 };
 203 static void kvm_cpu_accel_register_types(void)
 204 {
 205     type_register_static(&kvm_cpu_accel_type_info);
 206 }
 207 type_init(kvm_cpu_accel_register_types);