Re: [Qemu-devel] [PATCH] target-i386: enable x2apic by default on more recent CPU models

[Andreas Färber]

Am 20.01.2014 15:36, schrieb Eduardo Habkost:
> This enables x2apic on the following CPU models: Conroe, Penryn,
> Nehalem, Westmere, Opteron_G[12345].
> 
> 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.
> 
> About testing: Conroe, Penryn, Nehalem, Westemere and Opteron_G[123]
> have x2apic enabled on RHEL-6 since RHEL-6.0, so the presence of x2apic
> on those CPU models got lots of testing in the last few years. I want to
> eventually enable x2apic on all other CPU models as well, but it will
> require some testing to ensure it won't confuse guests.
> 
> This shouldn't affect TCG at all because features not supported by TCG
> are automatically and silently disabled by QEMU when initializing the
> CPU.
> 
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
> v1 was sent in September 2013:
>   Message-Id: <address@hidden>
>   http://article.gmane.org/gmane.comp.emulators.qemu/234541
> 
> It got an Acked-by from Gleb but it was ignored by all maintainers.

Sorry, was still unread in my inbox. What changed between this version
and said v1? Just moving to _1_7? I.e. should I add back Gleb's Acked-by
before your Sob when applying?

Andreas

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