From: "Peter Huang(Peng)" <peter.huangpeng@huawei.com>
To: Eduardo Habkost <ehabkost@redhat.com>,
libvir-list@redhat.com, qemu-devel@nongnu.org,
Jiri Denemark <jdenemar@redhat.com>
Subject: [Qemu-devel] [Solved]FYI//Re: [Question] why x2apic's set by default without host support(on Nehalem CPU).
Date: Wed, 24 Jul 2013 10:54:57 +0800 [thread overview]
Message-ID: <51EF4201.9040802@huawei.com> (raw)
In-Reply-To: <51EF2469.1090402@huawei.com>
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FYI, just for information sharing.
KVM emulated x2apic feature no matter host supports it or not.
You can get the code from arch/x86/kvm/cpuid.c.
kvm_dev_ioctl_get_supported_cpuid ()->do_cpuid_ent()
/* we support x2apic emulation even if host does not support
* it since we emulate x2apic in software */
entry->ecx |= F(*X2APIC*);
QEMU will get this feature through kvm_ioctl().
On 2013-07-24 8:48, Peter Huang(Peng) wrote:
> Hi,Jiri
>
> Thanks for replying.
>
> So why VM identified different features from host is due to the hypervisor filtering.
> I will dig into the hypervisor of how it filter features, and update status later.
>
> Thanks again.
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prev parent reply other threads:[~2013-07-24 2:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-22 11:24 [Qemu-devel] [Question] why x2apic's set by default without host support(on Nehalem CPU) Peter Huang(Peng)
2013-07-22 12:36 ` Peter Huang(Peng)
2013-07-22 23:55 ` Marcelo Tosatti
2013-07-23 2:38 ` Peter Huang(Peng)
2013-07-22 13:41 ` Eduardo Habkost
2013-07-23 2:44 ` Peter Huang(Peng)
2013-07-23 11:27 ` Jiri Denemark
2013-07-24 0:48 ` Peter Huang(Peng)
2013-07-24 2:54 ` Peter Huang(Peng) [this message]
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