Re: [PATCH 3/4] kvm, memory-hotplug: Update ept identity pagetable when it is migrated.

From: Tang Chen
Date: Wed Jul 02 2014 - 21:18:35 EST


On 07/03/2014 12:34 AM, Gleb Natapov wrote:
On Wed, Jul 02, 2014 at 05:00:36PM +0800, Tang Chen wrote:
ept identity pagetable is pinned in memory, and as a result it cannot be
migrated/hot-removed.

But actually it doesn't need to be pinned in memory.

This patch introduces a new vcpu request: KVM_REQ_MIGRATE_EPT to reset ept
indetity pagetable related variable. This request will be made when
kvm_mmu_notifier_invalidate_page() is called when the page is unmapped
from the qemu user space to reset kvm->arch.ept_identity_pagetable to NULL.
And will also be made when ept violation happens to reset
kvm->arch.ept_identity_pagetable to the new page.

kvm->arch.ept_identity_pagetable is never used as a page address, just
boolean null/!null to see if identity pagetable is initialized. I do
not see why would we want to track its address at all. Changing it to bool
and assigning true during initialization should be enough.

OK, followed.
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