linux-kernel - Re: [Regression, bisected] a3e06bbe8445f57eb949e6474c5a9b30f24d2057: KVM: emulate lapic tsc deadline timer for guest"

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Message-ID: <4EF1A454.8070503@redhat.com>
Date:	Wed, 21 Dec 2011 11:18:12 +0200
From:	Avi Kivity <avi@...hat.com>
To:	"Liu, Jinsong" <jinsong.liu@...el.com>
CC:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Alexey Zaytsev <alexey.zaytsev@...il.com>,
	Kernel development list <linux-kernel@...r.kernel.org>,
	Jan Kiszka <jan.kiszka@...mens.com>,
	Marcelo Tosatti <mtosatti@...hat.com>,
	"Garrett D'Amore" <garrett@...enta.com>
Subject: Re: [Regression, bisected] a3e06bbe8445f57eb949e6474c5a9b30f24d2057:
 KVM: emulate lapic tsc deadline timer for guest"

On 12/20/2011 09:21 PM, Liu, Jinsong wrote:
> Yes, my fault to say 'walk around' before knowing Alex's issue clearly.
>
> After Alex send his last email to clarify the situation, I have checked the bug.
> Basically it caused from
> 1. qemu didn't issue KVM_CREATE_IRQCHIP, hence irqchip_in_kernel(kvm) fail when setup vcpu lapic logic at kvm_arch_vcpu_init();
> 2. tsc deadline work based on vcpu lapic, hence break illumos;
>
> A fix is to update cpuid, as you said, setting it after KVM_CREATE_IRQCHIP. 

Wait, qemu set up a vcpu with TSC deadline timer in cpuid, but with
userspace apic?  Then it was clearly lying, since qemu doesn't implement
the TSC deadline timer.

> I just wonder is there any better solution? so I ask Alex his environment to setup at my side to do more test.
> If you think kvm tsc deadline timer patch itself not clean, please tell me.
>

Alexey, did you use -cpu host?

-- 
error compiling committee.c: too many arguments to function

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