lkml.org 
[lkml]   [2013]   [Jun]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v3 0/6] KVM: MMU: fast invalidate all mmio sptes
On 06/18/2013 10:26 PM, Paolo Bonzini wrote:
> Il 07/06/2013 10:51, Xiao Guangrong ha scritto:
>> Changelog:
>> V3:
>> All of these changes are from Gleb's review:
>> 1) rename RET_MMIO_PF_EMU to RET_MMIO_PF_EMULATE.
>> 2) smartly adjust kvm generation number in kvm_current_mmio_generatio()
>> to avoid kvm_memslots->generation overflow.
>>
>> V2:
>> - rename kvm_mmu_invalid_mmio_spte to kvm_mmu_invalid_mmio_sptes
>> - use kvm->memslots->generation as kvm global generation-number
>> - fix comment and codestyle
>> - init kvm generation close to mmio wrap-around value
>> - keep kvm_mmu_zap_mmio_sptes
>>
>> The current way is holding hot mmu-lock and walking all shadow pages, this
>> is not scale. This patchset tries to introduce a very simple and scale way
>> to fast invalidate all mmio sptes - it need not walk any shadow pages and hold
>> any locks.
>>
>> The idea is simple:
>> KVM maintains a global mmio valid generation-number which is stored in
>> kvm->memslots.generation and every mmio spte stores the current global
>> generation-number into his available bits when it is created
>>
>> When KVM need zap all mmio sptes, it just simply increase the global
>> generation-number. When guests do mmio access, KVM intercepts a MMIO #PF
>> then it walks the shadow page table and get the mmio spte. If the
>> generation-number on the spte does not equal the global generation-number,
>> it will go to the normal #PF handler to update the mmio spte
>>
>> Since 19 bits are used to store generation-number on mmio spte, we zap all
>> mmio sptes when the number is round
>>
>> Xiao Guangrong (6):
>> KVM: MMU: retain more available bits on mmio spte
>> KVM: MMU: store generation-number into mmio spte
>> KVM: MMU: make return value of mmio page fault handler more readable
>> KVM: MMU: fast invalidate all mmio sptes
>> KVM: MMU: add tracepoint for check_mmio_spte
>> KVM: MMU: init kvm generation close to mmio wrap-around value
>>
>> arch/x86/include/asm/kvm_host.h | 2 +-
>> arch/x86/kvm/mmu.c | 131 ++++++++++++++++++++++++++++++++--------
>> arch/x86/kvm/mmu.h | 17 ++++++
>> arch/x86/kvm/mmutrace.h | 34 +++++++++--
>> arch/x86/kvm/paging_tmpl.h | 10 ++-
>> arch/x86/kvm/vmx.c | 12 ++--
>> arch/x86/kvm/x86.c | 11 +++-
>> 7 files changed, 177 insertions(+), 40 deletions(-)
>>
>
> Xiao, is it time to add more comments to the code or update
> Documentation/virtual/kvm/mmu.txt?

Yes. it is.

We missed to update mmu.txt for a long time. I will post a separate patchset
to update it to the current mmu code.

> Don't worry about the English, it is
> more than understandable and I can help with the editing.

Okay. Thank you in advance, Paolo! :)




\
 
 \ /
  Last update: 2013-06-19 05:21    [W:0.167 / U:0.208 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site