[RFC PATCH v4 04/12] x86/sgx: Require userspace to define enclave pages' protection bits

[Jarkko Sakkinen]

On Fri, Jun 21, 2019 at 04:07:53AM +0300, Jarkko Sakkinen wrote:
> /**
>  * sgx_calc_vma_prot_intersection() - Calculate intersection of the permissions
>  *				      for a VMA
>  * @encl:	an enclave
>  * @vma:	a VMA inside the enclave
>  *
>  * Iterate through the page addresses inside the VMA and calculate a bitmask
>  * of permissions that all pages have in common. Page addresses that do
>  * not have an associated enclave page are interpreted to zero
>  * permissions.
>  */
> 
> > +static unsigned long sgx_allowed_rwx(struct sgx_encl *encl,
> > +				     struct vm_area_struct *vma)
> 
> Suggestion for the name: sgx_calc_vma_prot_intersection()

And have you thought off caching these results?

I.e. hold the result for each VMA and only recalculate when the old
value is dirty. Just a random thought, zero analysis but though that
good to mention anyway.

/Jarkko