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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 <josh.beavers@gmail.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
hifive-unleashed-5.1
Jason Gunthorpe 2017-03-10 11:34:20 -07:00 committed by Doug Ledford
parent 86f46aba8d
commit cb88645596
2 changed files with 4 additions and 4 deletions
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4
drivers/infiniband/sw/rdmavt/mmap.c
View File

@ -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);

4
drivers/infiniband/sw/rxe/rxe_mmap.c
View File

@ -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);