On Fri, May 30, 2025 at 03:25:19PM -0300, Jason Gunthorpe wrote: > On Fri, May 30, 2025 at 11:23:02AM -0700, Nicolin Chen wrote: > > On Fri, May 30, 2025 at 02:40:37PM -0300, Jason Gunthorpe wrote: > > > On Fri, May 30, 2025 at 10:38:24AM -0700, Nicolin Chen wrote: > > > > On Fri, May 30, 2025 at 01:14:55PM -0300, Jason Gunthorpe wrote: > > > > > On Sat, May 17, 2025 at 08:21:31PM -0700, Nicolin Chen wrote: > > > > > > + offset = > > > > > > + cmd->nesting_parent_iova - > > > > > > PAGE_ALIGN(cmd->nesting_parent_iova); > > > > > > + max_npages = DIV_ROUND_UP(offset + cmd->length, PAGE_SIZE); > > > > > > > > > > This should probably be capped to PAGE_SIZE/sizeof(void *), return > > > > > EINVAL if not > > > > > > > > Hmm, mind elaborating where this PAGE_SIZE/sizeof comes from? > > > > > > We can usually allocate up to a PAGE_SIZE without too much > > > trouble. Beyond that it gets more likely to fail. > > > > If PAGE_SIZE=4096, the upper limit for max_npages is 512, i.e. the > > max size of a guest queue is 2MB? It seems to be too small, as the > > VMM can use a larger huge page size to back the guest queue? > > May need to make a new API that returns a bio_vec or something else > more efficient then :\
Hmm, that sounds like a rabbit hole :-\ Let me leave a FIXME at this max_npages calculation instead.. Thanks Nicolin
