cxl/region: Fix memdev reuse check

commit f04facfb993de47e2133b2b842d72b97b1c50162 upstream.

Due to a typo, the check of whether or not a memdev has already been
used as a target for the region (above code piece) will always be
skipped. Given a memdev with more than one HDM decoder, an interleaved
region can be created that maps multiple HPAs to the same DPA. According
to CXL spec 3.0 8.1.3.8.4, "Aliasing (mapping more than one Host
Physical Address (HPA) to a single Device Physical Address) is
forbidden."

Fix this by using existing iterator for memdev reuse check.

Cc: <stable@vger.kernel.org>
Fixes: 384e624bb211 ("cxl/region: Attach endpoint decoders")
Signed-off-by: Fan Ni <fan.ni@samsung.com>
Link: https://lore.kernel.org/r/20221107212153.745993-1-fan.ni@samsung.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index f9ae5ad284ffb0c8ac3e16a84d8896052006dc51..c7152b4bd9ebb3b6584040cac8838d0700409dcd 100644 (file)
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -1226,7 +1226,7 @@ static int cxl_region_attach(struct cxl_region *cxlr,
                struct cxl_endpoint_decoder *cxled_target;
                struct cxl_memdev *cxlmd_target;
 
-               cxled_target = p->targets[pos];
+               cxled_target = p->targets[i];
                if (!cxled_target)
                        continue;