[18/23] cxl/region: Only allow CXL capable targets

Commit Message

Ben Widawsky July 23, 2021, 9:06 p.m. UTC

A cxl_memdev exists for all CXL endpoints that support the CXL.io
protocol. If that device cannot participate in CXL.mem protocol, then it
cannot be part of a region's interleave set.

The ABI allows setting a target which is currently not CXL.mem capable
and only will fail when the binding to the region driver occurs. This is
in line with the other configuration parameters which are only strictly
validated when the driver gets bound to the region.

Signed-off-by: Ben Widawsky <[e-mail]>
---
 drivers/cxl/mem.h    | 5 +++++
 drivers/cxl/region.c | 8 +++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

Patch

diff --git a/drivers/cxl/mem.h b/drivers/cxl/mem.h
index 4f3ac1ccee0a..27e142cb0c55 100644
--- a/drivers/cxl/mem.h
+++ b/drivers/cxl/mem.h
@@ -93,4 +93,9 @@  struct cxl_mem {
 	struct range ram_range;
 };
 
+static inline bool is_cxl_mem_capable(struct cxl_memdev *cxlmd)
+{
+	return false;
+}
+
 #endif /* __CXL_MEM_H__ */
diff --git a/drivers/cxl/region.c b/drivers/cxl/region.c
index 1e996ffc0f22..d625dd81c13a 100644
--- a/drivers/cxl/region.c
+++ b/drivers/cxl/region.c
@@ -63,11 +63,17 @@  static int bind_region(struct cxl_region *region)
 		return -ENXIO;
 	}
 
-	for (i = 0; i < region->eniw; i++)
+	for (i = 0; i < region->eniw; i++) {
 		if (!region->targets[i]) {
 			trace_cxl_region_bind(region, "Missing memory device target");
 			return -ENXIO;
 		}
+		if (!is_cxl_mem_capable(region->targets[i])) {
+			trace_cxl_region_bind(region,
+					      "Target isn't CXL.mem capable");
+			return -ENODEV;
+		}
+	}
 
 	rc = allocate_region_addr(region);
 	if (rc)