infiniband: Fix alignment of mmap cookies to support VIPT caching

When vmalloc_user is used to create memory that is supposed to be mmap'd to user space, it is necessary for the mmap cookie (eg the offset) to be aligned to SHMLBA. This creates a situation where all virtual mappings of the same physical page share the same virtual cache index and guarantees VIPT coherence. Otherwise the cache is non-coherent and the kernel will not see writes by userspace when reading the shared page (or vice-versa). Reported-by: Josh Beavers <[email protected]> Signed-off-by: Jason Gunthorpe <[email protected]> Signed-off-by: Doug Ledford <[email protected]>
kyagi · Mar 24, 2017 · cb88645 · cb88645
1 parent 86f46ab
commit cb88645
Show file tree

Hide file tree

Showing 2 changed files with 4 additions and 4 deletions.
diff --git a/drivers/infiniband/sw/rdmavt/mmap.c b/drivers/infiniband/sw/rdmavt/mmap.c
@@ -170,9 +170,9 @@ struct rvt_mmap_info *rvt_create_mmap_info(struct rvt_dev_info *rdi,
 
 	spin_lock_irq(&rdi->mmap_offset_lock);
 	if (rdi->mmap_offset == 0)
-		rdi->mmap_offset = PAGE_SIZE;
+		rdi->mmap_offset = ALIGN(PAGE_SIZE, SHMLBA);
 	ip->offset = rdi->mmap_offset;
-	rdi->mmap_offset += size;
+	rdi->mmap_offset += ALIGN(size, SHMLBA);
 	spin_unlock_irq(&rdi->mmap_offset_lock);
 
 	INIT_LIST_HEAD(&ip->pending_mmaps);

diff --git a/drivers/infiniband/sw/rxe/rxe_mmap.c b/drivers/infiniband/sw/rxe/rxe_mmap.c
@@ -156,10 +156,10 @@ struct rxe_mmap_info *rxe_create_mmap_info(struct rxe_dev *rxe,
 	spin_lock_bh(&rxe->mmap_offset_lock);
 
 	if (rxe->mmap_offset == 0)
-		rxe->mmap_offset = PAGE_SIZE;
+		rxe->mmap_offset = ALIGN(PAGE_SIZE, SHMLBA);
 
 	ip->info.offset = rxe->mmap_offset;
-	rxe->mmap_offset += size;
+	rxe->mmap_offset += ALIGN(size, SHMLBA);
 
 	spin_unlock_bh(&rxe->mmap_offset_lock);