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Date:	Thu, 17 Jul 2014 21:34:20 +0800
From:	Tang Chen <>
To:	Gleb Natapov <>
CC:	Jan Kiszka <>, <>,
	<>, <>,
	<>, <>,
	<>, <>
Subject: Re: [PATCH v2 5/5] kvm, mem-hotplug: Do not pin apic access page
 in memory.

Hi Gleb,

On 07/15/2014 08:40 PM, Gleb Natapov wrote:
>> And yes, we have the problem you said here. We can migrate the page while L2
>> vm is running.
>> So I think we should enforce L2 vm to exit to L1. Right ?
> We can request APIC_ACCESS_ADDR reload during L2->L1 vmexit emulation, so
> if APIC_ACCESS_ADDR changes while L2 is running it will be reloaded for L1 too.

Sorry, I think I don't quite understand the procedure you are talking 
about here.

Referring to the code, I think we have three machines: L0(host), L1 and L2.
And we have two types of vmexit: L2->L1 and L2->L0.  Right ?

We are now talking about this case: L2 and L1 shares the apic page.

Using patch 5/5, when apic page is migrated on L0, mmu_notifier will 
notify L1,
and update L1's VMCS. At this time, we are in L0, not L2. Why cannot we 
the L2's VMCS at the same time ?  Is it because we don't know how many 
L2 vms
there are in L1 ?

And, when will L2->L1 vmexit happen ?  When we enforce L1 to exit to L0 by
calling make_all_cpus_request(), is L2->L1 vmexit triggered automatically ?

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