On 29/05/2017 06:02, Peter Xu wrote:
> The IOTLB that it returned didn't guarantee that page_mask is indeed a
> so-called page mask. That won't affect current usage since now only
> vhost is using it (vhost API allows arbitary IOTLB range). However we
> have IOTLB scemantic and we should best follow it. This patch fixes this
> issue to make sure the page_mask is always a valid page mask.
>
> Fixes: a764040 ("exec: abstract address_space_do_translate()")
> Signed-off-by: Peter Xu <pet...@redhat.com>
> ---
> Sorry please use this one. The codes is merely the same, just avoided
> moving the codes around unnecessarily.
> ---
> exec.c | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index ff16f04..3db247c 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -529,16 +529,14 @@ IOMMUTLBEntry
> address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr,
> section.offset_within_region;
>
> if (plen == (hwaddr)-1) {
> - /*
> - * We use default page size here. Logically it only happens
> - * for identity mappings.
> - */
> - plen = TARGET_PAGE_SIZE;
> + /* If not specified during translation, use default mask */
> + plen = TARGET_PAGE_MASK;
> + } else {
> + /* Make it a valid page mask */
> + assert(plen);
> + plen = (1ULL << (63 - clz64(plen))) - 1;
Would pow2floor be better?
Thanks,
Paolo
> }
>
> - /* Convert to address mask */
> - plen -= 1;
> -
> return (IOMMUTLBEntry) {
> .target_as = section.address_space,
> .iova = addr & ~plen,
>
