Re: [PATCH 0/4] kvm, mem-hotplug: Do not pin ept identity pagetable and apic access page.

[Tang Chen <tangchen@cn.fujitsu.com>]

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.