Re: [Xen-devel] [V2 PATCH 7/9] x86/hvm: pkeys, add pkeys support for guest_walk_tables

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 27.11.15 at 10:52, <huaitong.han@xxxxxxxxx> wrote:
> @@ -90,6 +92,53 @@ static uint32_t set_ad_bits(void *guest_p, void *walk_p, 
> int set_dirty)
>      return 0;
>  }
>  
> +#if GUEST_PAGING_LEVELS >= 4
> +uint32_t leaf_pte_pkeys_check(struct vcpu *vcpu, uint32_t pfec,
> +                uint32_t pte_access, uint32_t pte_pkeys)
> +{
> +    bool_t pkru_ad, pkru_wd;
> +    bool_t ff, wf, uf, rsvdf, pkuf;
> +    unsigned int pkru = 0;

Pointless initializer.

> +    uf = pfec & PFEC_user_mode;
> +    wf = pfec & PFEC_write_access;
> +    rsvdf = pfec & PFEC_reserved_bit;
> +    ff = pfec & PFEC_insn_fetch;
> +    pkuf = pfec & PFEC_prot_key;
> +
> +    if ( !cpu_has_xsave || !pkuf || is_pv_vcpu(vcpu) )
> +        return 0;
> +
> +    vcpu_save_fpu(vcpu);
> +    pkru = *(unsigned int*)get_xsave_addr(vcpu->arch.xsave_area, 
> XSTATE_PKRU);

I.e. you really want to _only_ save that one component.

> @@ -106,6 +155,7 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
>  #if GUEST_PAGING_LEVELS >= 4 /* 64-bit only... */
>      guest_l3e_t *l3p = NULL;
>      guest_l4e_t *l4p;
> +    uint32_t pkeys;

No reason I can see to use a fixed width type here - unsigned int
ought to be fine.

> @@ -199,6 +250,9 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
>      
>      pse1G = (gflags & _PAGE_PSE) && guest_supports_1G_superpages(v); 
>  
> +    if (pse1G && leaf_pte_pkeys_check(v, pfec, gflags, pkeys))

Coding style (more further down).

Jan


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