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 78344e4d4215bf0dbfd3dacf876f09380ebef42e..dbf3413aa6178d6ca67b855d682a165d24b826d1 100644 (file)
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -1225,7 +1225,7 @@ 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;