cxl/mem: Fix memory device capacity probing

The CXL Identify Memory Device output payload emits capacity in 256MB
units. The driver is treating the capacity field as bytes. This was
missed because QEMU reports bytes when it should report bytes / 256MB.

Fixes: 8adaf747c9f0 ("cxl/mem: Find device capabilities")
Reviewed-by: Vishal Verma <[email protected]>
Cc: Ben Widawsky <[email protected]>
Link: https://lore.kernel.org/r/161862021044.3259705.7008520073059739760.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <[email protected]>

diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 1b5078311f7d6dcdc2fd6a8ab1745b2eea01d887..2acc6173da36cee0f5630ebcad4ddcea07096b17 100644 (file)
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -4,6 +4,7 @@
 #include <linux/security.h>
 #include <linux/debugfs.h>
 #include <linux/module.h>
+#include <linux/sizes.h>
 #include <linux/mutex.h>
 #include <linux/cdev.h>
 #include <linux/idr.h>
@@ -1419,6 +1420,7 @@ out:
  */
 static int cxl_mem_identify(struct cxl_mem *cxlm)
 {
+       /* See CXL 2.0 Table 175 Identify Memory Device Output Payload */
        struct cxl_mbox_identify {
                char fw_revision[0x10];
                __le64 total_capacity;
@@ -1447,10 +1449,11 @@ static int cxl_mem_identify(struct cxl_mem *cxlm)
         * For now, only the capacity is exported in sysfs
         */
        cxlm->ram_range.start = 0;
-       cxlm->ram_range.end = le64_to_cpu(id.volatile_capacity) - 1;
+       cxlm->ram_range.end = le64_to_cpu(id.volatile_capacity) * SZ_256M - 1;
 
        cxlm->pmem_range.start = 0;
-       cxlm->pmem_range.end = le64_to_cpu(id.persistent_capacity) - 1;
+       cxlm->pmem_range.end =
+               le64_to_cpu(id.persistent_capacity) * SZ_256M - 1;
 
        memcpy(cxlm->firmware_version, id.fw_revision, sizeof(id.fw_revision));