diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2018-06-22 22:22:05 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-06-29 13:02:47 +0200 |
| commit | 2266d44311321a833d569cd4deb46cca6021d0e7 (patch) | |
| tree | 954cac47b13360c4ebafbc3f7cb2c4c2c31f9672 /target/i386 | |
| parent | 6f131f13e68d648a8e4f083c667ab1acd88ce4cd (diff) | |
i386/cpu: make -cpu host support monitor/mwait
When guest CPU PM is enabled, and with -cpu host, expose the host CPU
MWAIT leaf in the CPUID so guest can make good PM decisions.
Note: the result is 100% CPU utilization reported by host as host
no longer knows that the CPU is halted.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180622192148.178309-3-mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'target/i386')
| -rw-r--r-- | target/i386/cpu.c | 32 | ||||
| -rw-r--r-- | target/i386/cpu.h | 9 | ||||
| -rw-r--r-- | target/i386/kvm.c | 9 |
3 files changed, 40 insertions, 10 deletions
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index e6c2f8a22a..1e6a7d0a75 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -3959,11 +3959,11 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, } break; case 5: - /* mwait info: needed for Core compatibility */ - *eax = 0; /* Smallest monitor-line size in bytes */ - *ebx = 0; /* Largest monitor-line size in bytes */ - *ecx = CPUID_MWAIT_EMX | CPUID_MWAIT_IBE; - *edx = 0; + /* MONITOR/MWAIT Leaf */ + *eax = cpu->mwait.eax; /* Smallest monitor-line size in bytes */ + *ebx = cpu->mwait.ebx; /* Largest monitor-line size in bytes */ + *ecx = cpu->mwait.ecx; /* flags */ + *edx = cpu->mwait.edx; /* mwait substates */ break; case 6: /* Thermal and Power Leaf */ @@ -4804,13 +4804,25 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp) Error *local_err = NULL; static bool ht_warned; - if (xcc->host_cpuid_required && !accel_uses_host_cpuid()) { - char *name = x86_cpu_class_get_model_name(xcc); - error_setg(&local_err, "CPU model '%s' requires KVM", name); - g_free(name); - goto out; + if (xcc->host_cpuid_required) { + if (!accel_uses_host_cpuid()) { + char *name = x86_cpu_class_get_model_name(xcc); + error_setg(&local_err, "CPU model '%s' requires KVM", name); + g_free(name); + goto out; + } + + if (enable_cpu_pm) { + host_cpuid(5, 0, &cpu->mwait.eax, &cpu->mwait.ebx, + &cpu->mwait.ecx, &cpu->mwait.edx); + env->features[FEAT_1_ECX] |= CPUID_EXT_MONITOR; + } } + /* mwait extended info: needed for Core compatibility */ + /* We always wake on interrupt even if host does not have the capability */ + cpu->mwait.ecx |= CPUID_MWAIT_EMX | CPUID_MWAIT_IBE; + if (cpu->apic_id == UNASSIGNED_APIC_ID) { error_setg(errp, "apic-id property was not initialized properly"); return; diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 16c59b7099..8eaefeee3e 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1382,6 +1382,15 @@ struct X86CPU { /* if true the CPUID code directly forward host cache leaves to the guest */ bool cache_info_passthrough; + /* if true the CPUID code directly forwards + * host monitor/mwait leaves to the guest */ + struct { + uint32_t eax; + uint32_t ebx; + uint32_t ecx; + uint32_t edx; + } mwait; + /* Features that were filtered out because of missing host capabilities */ uint32_t filtered_features[FEATURE_WORDS]; diff --git a/target/i386/kvm.c b/target/i386/kvm.c index dc991f6aca..c5f72d645b 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -366,6 +366,15 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function, if (!kvm_irqchip_in_kernel()) { ret &= ~CPUID_EXT_X2APIC; } + + if (enable_cpu_pm) { + int disable_exits = kvm_check_extension(s, + KVM_CAP_X86_DISABLE_EXITS); + + if (disable_exits & KVM_X86_DISABLE_EXITS_MWAIT) { + ret |= CPUID_EXT_MONITOR; + } + } } else if (function == 6 && reg == R_EAX) { ret |= CPUID_6_EAX_ARAT; /* safe to allow because of emulated APIC */ } else if (function == 7 && index == 0 && reg == R_EBX) { |