On Tue, Apr 29, 2025 at 02:46:25PM -0700, Nicolin Chen wrote:
On Tue, Apr 29, 2025 at 09:35:07PM +0000, Pranjal Shrivastava wrote:
On Tue, Apr 29, 2025 at 02:05:12PM -0700, Nicolin Chen wrote:
On Tue, Apr 29, 2025 at 08:55:47PM +0000, Pranjal Shrivastava wrote:
On Tue, Apr 29, 2025 at 01:39:09PM -0700, Nicolin Chen wrote:
On Tue, Apr 29, 2025 at 08:34:56PM +0000, Pranjal Shrivastava wrote:
On Tue, Apr 29, 2025 at 08:24:33PM +0000, Pranjal Shrivastava wrote: > On Fri, Apr 25, 2025 at 10:58:08PM -0700, Nicolin Chen wrote: > > + struct iommufd_mmap *immap; > > + int rc; > > + > > + if (WARN_ON_ONCE(!immap_id)) > > + return -EINVAL; > > + if (base & ~PAGE_MASK) > > + return -EINVAL; > > + if (!size || size & ~PAGE_MASK) > > + return -EINVAL; > > + > > + immap = kzalloc(sizeof(*immap), GFP_KERNEL); > > + if (!immap) > > + return -ENOMEM; > > + immap->pfn_start = base >> PAGE_SHIFT; > > + immap->pfn_end = immap->pfn_start + (size >> PAGE_SHIFT) - 1; > > + > > + rc = mtree_alloc_range(&ictx->mt_mmap, immap_id, immap, sizeof(immap), > > I believe this should be sizeof(*immap) ?
Ugh, Sorry, shouldn't this be size >> PAGE_SHIFT (num_indices to alloc) ?
mtree_load() returns a "struct iommufd_map *" pointer.
I'm not talking about mtree_load. I meant mtree_alloc_range takes in a "size" parameter, which is being passed as sizeof(imap) in this patch. IIUC, the mtree_alloc_range, via mas_empty_area, gets a range that is sufficient for the given "size".
Now in this case, "size" would be the no. of pfns which are mmap-able. By passing sizeof(immap), we're simply reserving sizeof(ptr) i.e. 8 pfns for a 64-bit machine. Whereas we really, just want to reserve a range for size >> PAGE_SHIFT pfns.
But we are not storing pfns but the immap pointer..
Ohh... so we are storing the raw pointer in the mtree.. I got confused with the `LONG_MAX >> PAGE_SHIFT`.. Sorry about the confusion!
Yes. We want the pointer at mtree_load(). The pfn range is for validation after mtree_load(). And we are likely to stuff more bits into the immap structure for other verifications.
Ack. Got it.
Thanks Nicolin
Thanks Praan