On 21/06/2016 05:12, Bandan Das wrote:
>
> static int is_shadow_present_pte(u64 pte)
> {
> - return pte & PT_PRESENT_MASK && !is_mmio_spte(pte);
> + int xbit = shadow_xonly_valid ? pte & shadow_x_mask : 0;
> +
> + return (pte & PT_PRESENT_MASK) | xbit
> + && !is_mmio_spte(pte);
> }
You can change this to just:
return
(pte & (PT_PRESENT_MASK | shadow_x_mask)) &&
!is_mmio_spte(pte);
because you know this is only called on a valid spte. Reserved bits are
checked elsewhere (and shouldn't be there anyway!).
> static int is_large_pte(u64 pte)
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index bc019f7..9f5bd06 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -133,7 +133,12 @@ static inline int FNAME(is_present_gpte)(unsigned long pte)
> #if PTTYPE != PTTYPE_EPT
> return is_present_gpte(pte);
> #else
> - return pte & 7;
> + /*
> + * For EPT, bits [2:0] can be 001, 100 or 111
> + * Further, for 100, logical processor should support
> + * execute-only.
> + */
> + return (pte & 1) || (shadow_xonly_valid && (pte & 4));
> #endif
Likewise, is_present_gpte is always followed by an is_rsvd_bits_set
check, which does check for execute-only. Modify
reset_tdp_shadow_zero_bits_mask to pass the right execonly value to
__reset_rsvds_bits_mask_ept, and you can leave is_present_gpte as is.
Paolo
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