From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Longpeng (Mike)" <longpeng2@huawei.com>
Subject: A problem about optimize the kvm_vcpu_on_spin
Date: Mon, 14 Nov 2016 09:44:57 +0800
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Cc: "Wubin (H)" <wu.wubin@huawei.com>,
        zhaoshenglong <zhaoshenglong@huawei.com>,
        kvm <kvm@vger.kernel.org>
To: Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>
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Hi Paolo and Radim,

Intel sdm vol3 ch-25.1.3 (p-1074) said: The “PAUSE-loop exiting” VM-execution
control is ignored if CPL > 0.

Does this means that only guest's kernelspace spinlock could causes VMexit due
to "pause-loop exiting" ?

If so, I think the kvm_vcpu_on_spin should selects a (currently not running)vcpu
which cpl=0 to boost, because the cpl>0 vcpus are not the lock-holder. (suppose
the guest isn't RT-linux)

What about your opinion ?

-- 
Regards,
Longpeng(Mike)