From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50423) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WG8ba-0001x5-9G for qemu-devel@nongnu.org; Wed, 19 Feb 2014 09:58:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WG8bU-0005PC-6I for qemu-devel@nongnu.org; Wed, 19 Feb 2014 09:58:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:2431) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WG8bT-0005P6-Ss for qemu-devel@nongnu.org; Wed, 19 Feb 2014 09:58:28 -0500 From: Eduardo Habkost Date: Wed, 19 Feb 2014 11:58:12 -0300 Message-Id: <1392821892-26682-4-git-send-email-ehabkost@redhat.com> In-Reply-To: <1392821892-26682-1-git-send-email-ehabkost@redhat.com> References: <1392821892-26682-1-git-send-email-ehabkost@redhat.com> Subject: [Qemu-devel] [PATCH 3/3] target-i386: Enable x2apic by default on KVM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, =?UTF-8?q?Andreas=20F=C3=A4rber?= Cc: Peter Maydell , "Michael S. Tsirkin" , Bandan Das , Anthony Liguori , Igor Mammedov , Paolo Bonzini , Richard Henderson 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 --- 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) 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) -- 1.8.5.3