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.