From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Mon, 06 Feb 2012 20:22:28 +0000
Subject: Re: [PATCH v2] KVM: Factor out kvm_vcpu_kick to arch-generic code
Message-Id: <20120206202228.GA23796@amt.cnet>
List-Id: <kvm-ppc.vger.kernel.org>
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 <20120206182504.GC19821@amt.cnet>
 <4F3032AC.10809@web.de>
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To: Jan Kiszka <jan.kiszka@web.de>
Cc: Christoffer Dall <c.dall@virtualopensystems.com>, kvm@vger.kernel.org, Marc.Zyngier@arm.com, agraf@suse.de, kvm-ppc@vger.kernel.org, avi@redhat.com, tech@virtualopensystems.com

On Mon, Feb 06, 2012 at 09:06:04PM +0100, Jan Kiszka wrote:
> On 2012-02-06 19:25, Marcelo Tosatti wrote:
> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> >> index c38efd7..a1761ff 100644
> >> --- a/arch/x86/kvm/x86.c
> >> +++ b/arch/x86/kvm/x86.c
> >> @@ -2252,7 +2252,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> >>  		kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
> >>  		if (vcpu->cpu != cpu)
> >>  			kvm_migrate_timers(vcpu);
> >> -		vcpu->cpu = cpu;
> >>  	}
> > 
> > This is wrong, kvm_sched_in fails to see vcpu->cpu properly. Please
> > keep vcpu->cpu assignment in arch code.
> 
> True, but then kvm_sched_in is a better place for this assignment (as
> it's central), no?
> 
> Jan

Not necessarily. Arch code might want to have:

kvm_arch_vcpu_load()
{
	cpu = smp_processor_id();

	if (vcpu->cpu != cpu) {
		localize vcpu to cpu
		vcpu->cpu = cpu
	}

	call functions which use vcpu->cpu
}