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Re: [PATCH 1/5] mmu: mark spte present if the x bit is set

From Paolo Bonzini <pbonzini@redhat.com>
Newsgroups linux.kernel
Subject Re: [PATCH 1/5] mmu: mark spte present if the x bit is set
Date 2016-06-28 10:50 +0200
Message-ID <rOWSt-4vW-9@gated-at.bofh.it> (permalink)
References <rOSYx-1Xl-7@gated-at.bofh.it> <rOSYx-1Xl-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 28/06/2016 06:32, Bandan Das wrote:
> This is safe because is_shadow_present_pte() is called
> on host controlled page table and we know the spte is
> valid
> 
> Signed-off-by: Bandan Das <bsd@redhat.com>
> ---
>  arch/x86/kvm/mmu.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index def97b3..a50af79 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -304,7 +304,8 @@ static int is_nx(struct kvm_vcpu *vcpu)
>  
>  static int is_shadow_present_pte(u64 pte)
>  {
> -	return pte & PT_PRESENT_MASK && !is_mmio_spte(pte);
> +	return pte & (PT_PRESENT_MASK | shadow_x_mask) &&
> +		!is_mmio_spte(pte);

This should really be pte & 7 when using EPT.  But this is okay as an
alternative to a new shadow_present_mask.

Paolo

>  }
>  
>  static int is_large_pte(u64 pte)
> 

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Thread

[PATCH 1/5] mmu: mark spte present if the x bit is set Bandan Das <bsd@redhat.com> - 2016-06-28 06:40 +0200
  Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Paolo Bonzini <pbonzini@redhat.com> - 2016-06-28 10:50 +0200
    Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Bandan Das <bsd@redhat.com> - 2016-06-28 19:40 +0200
      Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Paolo Bonzini <pbonzini@redhat.com> - 2016-06-28 22:20 +0200
        Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Bandan Das <bsd@redhat.com> - 2016-06-28 22:40 +0200
          Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Paolo Bonzini <pbonzini@redhat.com> - 2016-06-28 22:50 +0200
            Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Bandan Das <bsd@redhat.com> - 2016-06-28 23:10 +0200
            Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Xiao Guangrong <guangrong.xiao@linux.intel.com> - 2016-06-29 05:10 +0200
            Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Wanpeng Li <kernellwp@gmail.com> - 2016-07-05 05:10 +0200
              Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Paolo Bonzini <pbonzini@redhat.com> - 2016-07-05 13:00 +0200
                Re: [PATCH 1/5] mmu: mark spte present if the x bit is set Wanpeng Li <kernellwp@gmail.com> - 2016-07-05 13:40 +0200

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