linux-kernel - [PATCH v4 0/6] kvm, mem-hotplug: Do not pin ept identity pagetable and apic access page.

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Date:	Wed, 27 Aug 2014 18:17:35 +0800
From:	Tang Chen <tangchen@...fujitsu.com>
To:	<gleb@...nel.org>, <mtosatti@...hat.com>, <nadav.amit@...il.com>,
	<jan.kiszka@....de>
CC:	<kvm@...r.kernel.org>, <laijs@...fujitsu.com>,
	<isimatu.yasuaki@...fujitsu.com>, <guz.fnst@...fujitsu.com>,
	<linux-kernel@...r.kernel.org>, <tangchen@...fujitsu.com>
Subject: [PATCH v4 0/6] kvm, mem-hotplug: Do not pin ept identity pagetable and apic access page.

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.

[For ept identity page]
Just do not pin it. When it is migrated, guest will be able to find the
new page in the next ept violation.

[For apic access page]
The hpa of apic access page is stored in VMCS APIC_ACCESS_ADDR pointer.
When apic access page is migrated, we update VMCS APIC_ACCESS_ADDR pointer
for each vcpu in addition.

NOTE: Tested with -cpu xxx,-x2apic option.
      But since nested vm pins some other pages in memory, if user uses nested
      vm, memory hot-remove will not work.

Change log v3 -> v4:
1. The original patch 6 is now patch 5. ( by Jan Kiszka <jan.kiszka@....de> )
2. The original patch 1 is now patch 6 since we should unpin apic access page
   at the very last moment.


Tang Chen (6):
  kvm: Use APIC_DEFAULT_PHYS_BASE macro as the apic access page address.
  kvm: Remove ept_identity_pagetable from struct kvm_arch.
  kvm: Make init_rmode_identity_map() return 0 on success.
  kvm, mem-hotplug: Reload L1' apic access page on migration in
    vcpu_enter_guest().
  kvm, mem-hotplug: Reload L1's apic access page on migration when L2 is
    running.
  kvm, mem-hotplug: Do not pin apic access page in memory.

 arch/x86/include/asm/kvm_host.h |   3 +-
 arch/x86/kvm/svm.c              |  15 +++++-
 arch/x86/kvm/vmx.c              | 103 +++++++++++++++++++++++++++-------------
 arch/x86/kvm/x86.c              |  22 +++++++--
 include/linux/kvm_host.h        |   3 ++
 virt/kvm/kvm_main.c             |  30 +++++++++++-
 6 files changed, 135 insertions(+), 41 deletions(-)

-- 
1.8.3.1

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