| Message ID | 1392821892-26682-4-git-send-email-ehabkost@redhat.com |
|---|---|
| State | New |
| Headers | show |
Am 19.02.2014 15:58, schrieb Eduardo Habkost: > When on KVM mode, enable x2apic by default on all CPU models. > > Normally we try to keep the CPU model definitions as close as the real > CPUs as possible, but x2apic can be emulated by KVM without host CPU > support for x2apic, and it improves performance by reducing APIC access > overhead. x2apic emulation is available on KVM since 2009 (Linux > 2.6.32-rc1), there's no reason for not enabling x2apic by default when > running KVM. > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > --- > hw/i386/pc_piix.c | 1 + > hw/i386/pc_q35.c | 2 ++ > target-i386/cpu.c | 1 + > 3 files changed, 4 insertions(+) > > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c > index dab0c78..cf12873 100644 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@ -260,6 +260,7 @@ static void pc_compat_1_7(QEMUMachineInitArgs *args) > { > smbios_type1_defaults = false; > gigabyte_align = false; > + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); > } > > static void pc_compat_1_6(QEMUMachineInitArgs *args) > diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c > index a7f6260..71b05f1 100644 > --- a/hw/i386/pc_q35.c > +++ b/hw/i386/pc_q35.c > @@ -244,6 +244,8 @@ static void pc_compat_1_7(QEMUMachineInitArgs *args) > { > smbios_type1_defaults = false; > gigabyte_align = false; > + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); > + > } > > static void pc_compat_1_6(QEMUMachineInitArgs *args) [snip] Needed rebase: diff --cc hw/i386/pc_piix.c index 5011c3a,ebd442e..0000000 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@@ -266,7 -266,7 +266,8 @@@ static void pc_compat_1_7(QEMUMachineIn { smbios_type1_defaults = false; gigabyte_align = false; + option_rom_has_mr = true; + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); } static void pc_compat_1_6(QEMUMachineInitArgs *args) diff --cc hw/i386/pc_q35.c index 4b0456a,71b05f1..0000000 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@@ -244,7 -244,8 +244,8 @@@ static void pc_compat_1_7(QEMUMachineIn { smbios_type1_defaults = false; gigabyte_align = false; + option_rom_has_mr = true; + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); - } static void pc_compat_1_6(QEMUMachineInitArgs *args) Andreas
On Wed, Mar 12, 2014 at 03:36:02PM +0100, Andreas Färber wrote: [...] > [snip] > > Needed rebase: > > diff --cc hw/i386/pc_piix.c > index 5011c3a,ebd442e..0000000 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@@ -266,7 -266,7 +266,8 @@@ static void pc_compat_1_7(QEMUMachineIn > { > smbios_type1_defaults = false; > gigabyte_align = false; > + option_rom_has_mr = true; > + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); > } > > static void pc_compat_1_6(QEMUMachineInitArgs *args) > diff --cc hw/i386/pc_q35.c > index 4b0456a,71b05f1..0000000 > --- a/hw/i386/pc_q35.c > +++ b/hw/i386/pc_q35.c > @@@ -244,7 -244,8 +244,8 @@@ static void pc_compat_1_7(QEMUMachineIn > { > smbios_type1_defaults = false; > gigabyte_align = false; > + option_rom_has_mr = true; > + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); > - > } > > static void pc_compat_1_6(QEMUMachineInitArgs *args) Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> (I am guessing there's no need to resubmit. That's right?)
Am 12.03.2014 16:42, schrieb Eduardo Habkost: > On Wed, Mar 12, 2014 at 03:36:02PM +0100, Andreas Färber wrote: > [...] >> [snip] >> >> Needed rebase: >> >> diff --cc hw/i386/pc_piix.c >> index 5011c3a,ebd442e..0000000 >> --- a/hw/i386/pc_piix.c >> +++ b/hw/i386/pc_piix.c >> @@@ -266,7 -266,7 +266,8 @@@ static void pc_compat_1_7(QEMUMachineIn >> { >> smbios_type1_defaults = false; >> gigabyte_align = false; >> + option_rom_has_mr = true; >> + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); >> } >> >> static void pc_compat_1_6(QEMUMachineInitArgs *args) >> diff --cc hw/i386/pc_q35.c >> index 4b0456a,71b05f1..0000000 >> --- a/hw/i386/pc_q35.c >> +++ b/hw/i386/pc_q35.c >> @@@ -244,7 -244,8 +244,8 @@@ static void pc_compat_1_7(QEMUMachineIn >> { >> smbios_type1_defaults = false; >> gigabyte_align = false; >> + option_rom_has_mr = true; >> + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); >> - >> } >> >> static void pc_compat_1_6(QEMUMachineInitArgs *args) > > Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> > > (I am guessing there's no need to resubmit. That's right?) Right, just FYI that there's changes happening on my branch and that things are still being prepared and retested for submission. Andreas
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index dab0c78..cf12873 100644 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@ -260,6 +260,7 @@ static void pc_compat_1_7(QEMUMachineInitArgs *args) { smbios_type1_defaults = false; gigabyte_align = false; + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); } static void pc_compat_1_6(QEMUMachineInitArgs *args) diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c index a7f6260..71b05f1 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -244,6 +244,8 @@ static void pc_compat_1_7(QEMUMachineInitArgs *args) { smbios_type1_defaults = false; gigabyte_align = false; + x86_cpu_compat_disable_kvm_features(FEAT_1_ECX, CPUID_EXT_X2APIC); + } static void pc_compat_1_6(QEMUMachineInitArgs *args) diff --git a/target-i386/cpu.c b/target-i386/cpu.c index d65ca26..089328e 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -369,6 +369,7 @@ static uint32_t kvm_default_features[FEATURE_WORDS] = { (1 << KVM_FEATURE_STEAL_TIME) | (1 << KVM_FEATURE_PV_EOI) | (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT), + [FEAT_1_ECX] = CPUID_EXT_X2APIC, }; void x86_cpu_compat_disable_kvm_features(FeatureWord w, uint32_t features)
When on KVM mode, enable x2apic by default on all CPU models. Normally we try to keep the CPU model definitions as close as the real CPUs as possible, but x2apic can be emulated by KVM without host CPU support for x2apic, and it improves performance by reducing APIC access overhead. x2apic emulation is available on KVM since 2009 (Linux 2.6.32-rc1), there's no reason for not enabling x2apic by default when running KVM. Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> --- hw/i386/pc_piix.c | 1 + hw/i386/pc_q35.c | 2 ++ target-i386/cpu.c | 1 + 3 files changed, 4 insertions(+)