Re: [PATCH v17 18/23] platform/x86: Intel SGX driver

[Dave Hansen]

On 12/17/18 11:37 AM, Jarkko Sakkinen wrote:
>> Suggestion:
>>
>> It looks like you only expect one VMA per enclave.  Things go bonkers if
>> this is not true.  So, instead of storing encl->mm, don't.  You can get
>> the mm from vma->vm_mm and you could just store encl->vma instead.
> The code actually supports having multiple VMAs per enclave.

That seems at least somewhat at odds with this comment:

> static void sgx_vma_open(struct vm_area_struct *vma)
> {
>         struct sgx_encl *encl = vma->vm_private_data;
> 
>         if (!encl)
>                 return;
> 
>         /* kref cannot underflow because ECREATE ioctl checks that there is only
>          * one single VMA for the enclave before proceeding.
>          */
>         kref_get(&encl->refcount);
> }