Message-ID: <53B4AF47.1080008@cn.fujitsu.com>
Date: Thu, 3 Jul 2014 09:17:59 +0800
From: Tang Chen <tangchen@cn.fujitsu.com>
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To: <gleb@kernel.org>
CC: Tang Chen <tangchen@cn.fujitsu.com>, <mtosatti@redhat.com>,
        <kvm@vger.kernel.org>, <laijs@cn.fujitsu.com>,
        <isimatu.yasuaki@jp.fujitsu.com>, <guz.fnst@cn.fujitsu.com>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/4] kvm, mem-hotplug: Do not pin ept identity pagetable
 and apic access page.
References: <1404291637-15048-1-git-send-email-tangchen@cn.fujitsu.com>
In-Reply-To: <1404291637-15048-1-git-send-email-tangchen@cn.fujitsu.com>
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Sender: linux-kernel-owner@vger.kernel.org

Hi Gleb,

On 07/02/2014 05:00 PM, Tang Chen wrote:
> Hi Gleb, Marcelo,
>
> Please help to review this patch-set.
>
> NOTE: This patch-set doesn't work properly.
>
>
> ept identity pagetable and apic access page in kvm are pinned in memory.
> As a result, they cannot be migrated/hot-removed.
>
> But actually they don't need to be pinned in memory.
>
> This patch-set introduces two new vcpu requests: KVM_REQ_MIGRATE_EPT and KVM_REQ_MIGRATE_APIC.
> These two requests are made when the two pages are migrated by the mmu_notifier
> to reset the related variable to unusable value. And will also be made when
> ept violation happens to reset new pages.
>
>
> [Known problem]
> After this patch-set applied, the two pages can be migrated/hot-removed.
> But after migrating apic access page, the guest died.
>
> The host physical address of apic access page is stored in VMCS. I reset
> it to 0 to stop guest from accessing it when it is unmapped by
> kvm_mmu_notifier_invalidate_page(). And reset it to new page's host physical
> address in tdp_page_fault(). But it seems that guest will access apic page
> directly by the host physical address.

Would you please to give some advice about this problem ?

Thanks.
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