Re: [PATCH 1/4] KVM: MMU: fix permission_fault()

From	Xiao Guangrong <guangrong.xiao@linux.intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/4] KVM: MMU: fix permission_fault()
Date	2016-03-30 04:00 +0200
Message-ID	<ridAm-6zf-9@gated-at.bofh.it> (permalink)
References	<rgzYm-2fh-7@gated-at.bofh.it> <rgAUq-2VM-15@gated-at.bofh.it> <ri5Wa-18l-1@gated-at.bofh.it> <ri8hj-2Tk-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 03/30/2016 04:09 AM, Paolo Bonzini wrote:
>
>
> On 29/03/2016 19:43, Xiao Guangrong wrote:
>> Based on the SDM:
>> PK flag (bit 5).
>> This flag is 1 if (1) IA32_EFER.LMA = CR4.PKE = 1; (2) the access
>> causing the page-fault exception was a data access; (3) the linear
>> address was a user-mode address with protection key i; and (5) the PKRU
>> register (see Section 4.6.2) is such that either (a) ADi = 1; or (b) the
>> following all hold: (i) WDi = 1; (ii) the access is a write access; and
>> (iii) either CR0.WP = 1 or the access causing the page-fault exception
>> was a user-mode access.
>>
>> So I think PKEY check and ordinary check are independent, i.e, PFEC.PKEY
>> may be set even if the on permission on the page table is not adequate.
>
> x86/access.flat is currently using the "other" definition, i.e., PFEC.PK
> is only set if W=1 or CR0.WP=0 && PFEC.U=0 or PFEC.W=0.  Can you use it
> (with ept=1 of course) to check what the processor is doing?
>

Sure.

And ept=1 is hard to trigger MMU issue, i am enabling PKEY on shadow
MMU, let's see what will happen. ;)

Thread

[PATCH 1/4] KVM: MMU: fix permission_fault() Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-03-25 14:30 +0100
  [PATCH 3/4] KVM: MMU: reduce the size of mmu_page_path Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-03-25 14:30 +0100
    Re: [PATCH 3/4] KVM: MMU: reduce the size of mmu_page_path Paolo Bonzini <pbonzini@redhat.com> - 2016-03-25 14:50 +0100
      Re: [PATCH 3/4] KVM: MMU: reduce the size of mmu_page_path Paolo Bonzini <pbonzini@redhat.com> - 2016-03-25 15:00 +0100
        Re: [PATCH 3/4] KVM: MMU: reduce the size of mmu_page_path Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-03-25 15:10 +0100
          Re: [PATCH 3/4] KVM: MMU: reduce the size of mmu_page_path Paolo Bonzini <pbonzini@redhat.com> - 2016-03-25 15:30 +0100
      Re: [PATCH 3/4] KVM: MMU: reduce the size of mmu_page_path Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-03-25 15:00 +0100
  Re: [PATCH 1/4] KVM: MMU: fix permission_fault() Paolo Bonzini <pbonzini@redhat.com> - 2016-03-25 14:40 +0100
    Re: [PATCH 1/4] KVM: MMU: fix permission_fault() Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-03-25 14:50 +0100
      Re: [PATCH 1/4] KVM: MMU: fix permission_fault() Paolo Bonzini <pbonzini@redhat.com> - 2016-03-25 15:00 +0100
  [PATCH 2/4] KVM: MMU: simplify the logic of __mmu_unsync_walk() Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-03-25 14:40 +0100
  Re: [PATCH 1/4] KVM: MMU: fix permission_fault() Paolo Bonzini <pbonzini@redhat.com> - 2016-03-25 15:30 +0100
    Re: [PATCH 1/4] KVM: MMU: fix permission_fault() Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-03-29 19:50 +0200
      Re: [PATCH 1/4] KVM: MMU: fix permission_fault() Paolo Bonzini <pbonzini@redhat.com> - 2016-03-29 22:20 +0200
        Re: [PATCH 1/4] KVM: MMU: fix permission_fault() Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-03-30 04:00 +0200
          Re: [PATCH 1/4] KVM: MMU: fix permission_fault() Paolo Bonzini <pbonzini@redhat.com> - 2016-03-30 08:40 +0200
            Re: [PATCH 1/4] KVM: MMU: fix permission_fault() Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-03-30 08:50 +0200

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