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RE: [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so)

Started by"Li, Liang Z" <liang.z.li@intel.com>
First post2016-12-13 05:10 +0100
Last post2016-12-13 12:10 +0100
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  RE: [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so) "Li, Liang Z" <liang.z.li@intel.com> - 2016-12-13 05:10 +0100
    Re: [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so) Paolo Bonzini <pbonzini@redhat.com> - 2016-12-13 12:10 +0100

#1540827 — RE: [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so)

From"Li, Liang Z" <liang.z.li@intel.com>
Date2016-12-13 05:10 +0100
SubjectRE: [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so)
Message-ID<sNMzD-4TT-7@gated-at.bofh.it>
> UMIP (User-Mode Instruction Prevention) is a feature of future Intel
> processors (Cannonlake?) that blocks SLDT, SGDT, STR, SIDT and SMSW from
> user-mode processes.
> 
> The idea here is to use virtualization intercepts to emulate UMIP; it slows
> down the instructions when they're executed in ring 0, but they are really
> never executed in practice.  On AMD systems it's possible to emulate it
> entirely; instead on Intel systems it's *almost* possible to emulate it,
> because SMSW doesn't cause a vmexit, and hence SMSW will not fault.
> 
> This patch series provides the infrastructure and implements it on Intel.  I
> tested it through kvm-unit-tests.
> 
> Still I think the idea is interesting, even if it's buggy for current Intel
> processors.  Any opinions?

Hi Paolo,

We intended to enable UMIP for KVM and found you had already worked on it. 
Do you have any plan for the following patch set? It's there anything else you expect
us help to do?

Thanks!
Liang

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#1540999

FromPaolo Bonzini <pbonzini@redhat.com>
Date2016-12-13 12:10 +0100
Message-ID<sNT85-tf-17@gated-at.bofh.it>
In reply to#1540827

On 13/12/2016 05:03, Li, Liang Z wrote:
> Hi Paolo,
> 
> We intended to enable UMIP for KVM and found you had already worked on it. 
> Do you have any plan for the following patch set? It's there anything else you expect
> us help to do?

Yes, I plan to resend these patches for 4.11.

Paolo

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