From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v8 2/3] x86, apicv: add virtual interrupt delivery support
Date: Mon, 7 Jan 2013 19:32:39 -0200
Message-ID: <20130107213239.GB31677@amt.cnet>
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Cc: Yang Zhang <yang.z.zhang@intel.com>, kvm@vger.kernel.org,
	haitao.shan@intel.com, Kevin Tian <kevin.tian@intel.com>
To: Gleb Natapov <gleb@redhat.com>
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On Mon, Jan 07, 2013 at 07:48:43PM +0200, Gleb Natapov wrote:
> > ioapic_write (or any other ioapic update)
> > lock()
> > perform update
> > make_all_vcpus_request(KVM_REQ_UPDATE_EOI_BITMAP) (*)
> > unlock()
> > 
> > (*) Similarly to TLB flush.
> > 
> > The advantage is that all work becomes vcpu local. The end result
> > is much simpler code.
> What complexity will it remove?

Synchronization between multiple CPUs (except the KVM_REQ_ bit
processing, which is infrastructure shared by other parts of KVM).

We agreed that performance is non issue here.