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Groups > linux.kernel > #1340574
| From | Paolo Bonzini <pbonzini@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3 00/11] KVM: x86: track guest page access |
| Date | 2016-02-23 13:20 +0100 |
| Message-ID | <r5k6C-5fs-9@gated-at.bofh.it> (permalink) |
| References | <r23lD-25X-3@gated-at.bofh.it> <r3S2K-4Vi-23@gated-at.bofh.it> <r4VKW-47A-19@gated-at.bofh.it> <r5bwm-7xA-5@gated-at.bofh.it> <r5e1b-JW-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 23/02/2016 06:44, Tian, Kevin wrote: >> From: Song, Jike >> Sent: Tuesday, February 23, 2016 11:02 AM >> >> +Kevin >> >> On 02/22/2016 06:05 PM, Xiao Guangrong wrote: >>> >>> On 02/19/2016 08:00 PM, Paolo Bonzini wrote: >>>> >>>> I still have a doubt: how are you going to handle invalidation of GPU >>>> shadow page tables if a device (emulated in QEMU or even vhost) does DMA >>>> to the PPGTT? >>> >>> I think Jike is the better one to answer this question, Jike, could you >>> please clarify it? :) >>> >> >> Sure :) >> >> Actually in guest PPGTT is manipulated by CPU rather than GPU. The >> PPGTT page table itself are plain memory, composed & modified by the >> GPU driver, i.e. by CPU in Non-Root mode. >> >> Given that, we write-protected guest PPGTT, when VM writes PPGTT, EPT >> violation rather than DMA fault happens. > > 'DMA to PPGTT' is NOT SUPPORTED on our vGPU device model. Today > Intel gfx driver doesn't use this method, and we explicitly list it as a > guest driver requirement to support a vGPU. If a malicious driver does > program DMA to modify PPGTT, it can only modify guest PPGTT instead > of shadow PPGTT (being guest invisible). So there is no security issue > either. Ok, thanks for confirming. Paolo
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Re: [PATCH v3 00/11] KVM: x86: track guest page access Jike Song <jike.song@intel.com> - 2016-02-23 04:10 +0100
RE: [PATCH v3 00/11] KVM: x86: track guest page access "Tian, Kevin" <kevin.tian@intel.com> - 2016-02-23 06:50 +0100
Re: [PATCH v3 00/11] KVM: x86: track guest page access Paolo Bonzini <pbonzini@redhat.com> - 2016-02-23 13:20 +0100
Re: [PATCH v3 00/11] KVM: x86: track guest page access Paolo Bonzini <pbonzini@redhat.com> - 2016-02-23 11:10 +0100
Re: [PATCH v3 00/11] KVM: x86: track guest page access Jike Song <jike.song@intel.com> - 2016-02-23 13:00 +0100
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