Re: [Qemu-devel] [PULL 13/24] hw/arm/smmu-common: VMSAv8-64 page table walk

[Peter Maydell]

On 4 May 2018 at 18:15, Peter Maydell <address@hidden> wrote:
> From: Eric Auger <address@hidden>
>
> This patch implements the page table walk for VMSAv8-64.

Hi Eric;

> + * get_block_pte_address - return block descriptor output address and block 
> size
> + * ARM ARM Figure D4-16 VMSAv8-64 level0, level1, and level 2 descriptor 
> formats
> + */
> +static inline hwaddr get_block_pte_address(uint64_t pte, int level,
> +                                           int granule_sz, uint64_t *bsz)
> +{
> +    int n = (granule_sz - 3) * (4 - level) + 3;
> +
> +    *bsz = 1 << n;

Coverity (CID 1391010) points out that this can overflow if n > 31,
because it's only doing 32-bit arithmetic.
I think this is possible for some page table formats, so using
"1ULL" rather than "1" should make coverity happy.

Incidentally, isn't
   int n = (granule_sz - 3) * (4 - level) + 3;
equivalent to
   int n = level_shift(level, granule_sz);
?

> +    return PTE_ADDRESS(pte, n);
> +}

thanks
-- PMM