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

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Date:	Wed, 2 Jul 2014 17:00:12 +0800
From:	Tang Chen <tangchen@...fujitsu.com>
To:	<gleb@...nel.org>, <mtosatti@...hat.com>
CC:	<kvm@...r.kernel.org>, <laijs@...fujitsu.com>,
	<isimatu.yasuaki@...fujitsu.com>, <guz.fnst@...fujitsu.com>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH 0/4] kvm, mem-hotplug: Do not pin ept identity pagetable and apic access page.

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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