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Re: [Qemu-devel] [PATCH 3/3] target-i386: Enable x2apic by default on KV
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH 3/3] target-i386: Enable x2apic by default on KVM |
Date: |
Wed, 12 Mar 2014 15:36:02 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 |
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 <address@hidden>
> ---
> 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
--
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- Re: [Qemu-devel] [PATCH 3/3] target-i386: Enable x2apic by default on KVM,
Andreas Färber <=