[PATCH v5 0/7] kvm, mem-hotplug: Do not pin ept identity pagetable and apic access page.

Tang Chen
2014-09-11T05:36:46Z

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 v4 -> v5:
1. Patch 5/7: Call kvm_reload_apic_access_page() unconditionally in nested_vmx_vmexit().
(From Gleb Natapov <gleb@kernel.org>)
2. Patch 6/7: Remove kvm_arch->apic_access_page. (From Gleb Natapov <gleb@kernel.org>)
3. Patch 7/7: Remove nested_vmx->apic_access_page.

Tang Chen (7):
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: Unpin and remove kvm_arch->apic_access_page.
kvm, mem-hotplug: Unpin and remove nested_vmx->apic_access_page.

arch/x86/include/asm/kvm_host.h | 4 +-
arch/x86/kvm/svm.c | 9 ++-
arch/x86/kvm/vmx.c | 139 ++++++++++++++++++++++------------------
arch/x86/kvm/x86.c | 24 +++++--
include/linux/kvm_host.h | 2 +
virt/kvm/kvm_main.c | 13 ++++
6 files changed, 122 insertions(+), 69 deletions(-)

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1.8.3.1