linux-kernel - Re: [PATCH v3 0/6] KVM: MMU: fast invalidate all mmio sptes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <51C1ED05.9040604@redhat.com>
Date:	Wed, 19 Jun 2013 19:40:21 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
CC:	gleb@...hat.com, avi.kivity@...il.com, mtosatti@...hat.com,
	linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH v3 0/6] KVM: MMU: fast invalidate all mmio sptes

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(-)
> 

Applied all to queue for now.  Will graduate to next after doing some
more tests.

Thanks!

Paolo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/