Re: [PATCH v8 0/8] kvm, mem-hotplug: Do not pin ept identity pagetable and apic access page.

[Tang Chen <tangchen@cn.fujitsu.com>]

On 09/24/2014 04:20 PM, Paolo Bonzini wrote:
> Il 24/09/2014 09:57, Tang Chen ha scritto:
>> 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.
>>
>> This patch-set is based on Linux 3.17.0-rc5.
>>
>> 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 v7->v8:
>> 1. Patch 1/9~3/9 were applied to kvm/queue by Paolo Bonzini <pbonzini@redhat.com>.
>>     Just resend them, no changes.
>> 2. Removed previous patch 4/9, which added unnecessary hook has_secondary_apic_access().
>> 3. Set kvm_x86_ops->set_apic_access_page_addr to NULL when hardware had no flexpriority
>>     functionality which actually exists only on x86.
>> 4. Moved declaration of kvm_arch_mmu_notifier_invalidate_page() to arch/*/include/asm/kvm_host.h.
>> 5. Removed useless set_apic_access_page_addr() hook for svm.
>>
>> Tang Chen (8):
>>    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's apic access page in vcpu_enter_guest().
>>    kvm: Rename make_all_cpus_request() to kvm_make_all_cpus_request() and
>>      make it non-static.
>>    kvm, mem-hotplug: Reload L1's apic access page on migration when L2 is
>>      running.
>>    kvm, mem-hotplug: Add arch specific mmu notifier to handle apic access
>>      migration.
>>    kvm, mem-hotplug: Unpin and remove kvm_arch->apic_access_page.
>>
>>   arch/arm/include/asm/kvm_host.h     |   5 ++
>>   arch/arm64/include/asm/kvm_host.h   |   5 ++
>>   arch/ia64/include/asm/kvm_host.h    |   7 ++
>>   arch/mips/include/asm/kvm_host.h    |   6 ++
>>   arch/powerpc/include/asm/kvm_host.h |   5 ++
>>   arch/s390/include/asm/kvm_host.h    |   8 +++
>>   arch/x86/include/asm/kvm_host.h     |   7 +-
>>   arch/x86/kvm/svm.c                  |   3 +-
>>   arch/x86/kvm/vmx.c                  | 130 ++++++++++++++++++++++++------------
>>   arch/x86/kvm/x86.c                  |  45 +++++++++++--
>>   include/linux/kvm_host.h            |   2 +
>>   virt/kvm/kvm_main.c                 |  13 ++--
>>   12 files changed, 180 insertions(+), 56 deletions(-)
>>
> Thanks for your persistence!  The patches look good, I'll test them and
> apply to kvm/queue.

Sure, thank you very much. :)