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

From: Tang Chen
Date: Wed Jul 02 2014 - 04:59:51 EST


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.


Tang Chen (4):
kvm: Add gfn_to_page_no_pin()
kvm: Add macro VMX_APIC_ACCESS_PAGE_ADDR
kvm, memory-hotplug: Update ept identity pagetable when it is
migrated.
kvm, mem-hotplug: Update apic access page when it is migrated.

arch/x86/include/asm/kvm_host.h | 3 +++
arch/x86/include/asm/vmx.h | 2 +-
arch/x86/kvm/mmu.c | 26 ++++++++++++++++++++++++++
arch/x86/kvm/svm.c | 3 ++-
arch/x86/kvm/vmx.c | 17 +++++++++++++----
arch/x86/kvm/x86.c | 36 ++++++++++++++++++++++++++++++++++++
include/linux/kvm_host.h | 3 +++
virt/kvm/kvm_main.c | 38 +++++++++++++++++++++++++++++++++++++-
8 files changed, 121 insertions(+), 7 deletions(-)

--
1.8.3.1

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