wbinvd();
/*
- * Try to workaround a bug (thanks to BenH)
+ * Try to workaround a bug (thanks to BenH):
* Set unmapped entries to a scratch page instead of 0.
* Any prefetches that hit unmapped entries won't get an bus abort
- * then.
+ * then. (P2P bridge may be prefetching on DMA reads).
*/
scratch = get_zeroed_page(GFP_KERNEL);
if (!scratch)