> +/*
> + * gmap_protect_pmd - remove access rights to memory and set pmd notification bits
> + * @pmdp: pointer to the pmd to be protected
> + * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
> + * @bits: notification bits to set
> + *
> + * Returns:
> + * 0 if successfully protected
> + * -ENOMEM if out of memory and
This cannot happen.
> + * -EAGAIN if a fixup is needed
> + * -EINVAL if unsupported notifier bits have been specified
> + *
> + * Expected to be called with sg->mm->mmap_sem in read and
> + * guest_table_lock held.
> + */
> +static int gmap_protect_pmd(struct gmap *gmap, unsigned long gaddr,
> + pmd_t *pmdp, int prot, unsigned long bits)
> +{
> + int pmd_i = pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID;
> + int pmd_p = pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT;
> +
> + /* Fixup needed */
> + if ((pmd_i && (prot != PROT_NONE)) || (pmd_p && (prot == PROT_WRITE)))
> + return -EAGAIN;
You should also return -EINVAL in case !PROT_WRITE is defined, as we
only support PROT_WRITE (we don't perform any protection!)
> + if (bits & GMAP_NOTIFY_MPROT)
> + pmd_val(*pmdp) |= _SEGMENT_ENTRY_GMAP_IN;
> +
> + /* Shadow GMAP protection needs split PMDs */
> + if (bits & GMAP_NOTIFY_SHADOW)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
--
Thanks,
David / dhildenb
