From 8a80d3d65cd06ee35b913d8517fb2f2319f8e70c Mon Sep 17 00:00:00 2001 From: Alison Schofield Date: Fri, 24 Jul 2026 13:37:17 -0700 Subject: [PATCH 1/3] cxl/pmem: Format the nvdimm serial number as unsigned decimal The CXL NVDIMM security passphrase key description and the nvdimm 'id' sysfs attribute are both derived from the CXL device serial number, but the serial number is not formatted consistently. The key description is formatted in hexadecimal while the 'id' attribute is formatted in decimal. As a result, ndctl stores the key using a decimal description while the kernel later looks it up using a hexadecimal description. For serial numbers of 10 and above, the descriptions no longer match, preventing automatic unlock after reboot. The decimal formatting has a second problem: both the key description and the 'id' attribute use the signed %lld format for a u64 PCIe Device Serial Number. Devices whose vendor OUI sets bit 63, such as Montage CXL devices, appear with negative decimal serial numbers. Format the security key description and 'id' attribute as unsigned decimal, %llu, and document that the 'id' attribute is an unsigned decimal value. The key lookup mismatch was exposed by CXL unit test cxl-security.sh when cxl_test mock serial numbers were extended to 10 and above. A work around is described for ndctl load-key users here: https://github.com/pmem/ndctl/issues/299 Cc: stable@vger.kernel.org Fixes: b5807c80b5bc ("cxl: add dimm_id support for __nvdimm_create()") Acked-by: Dan Williams Signed-off-by: Alison Schofield Link: https://patch.msgid.link/2c673a5ba0a8fa93ad160578e193bd556091fa95.1784924949.git.alison.schofield@intel.com Signed-off-by: Dave Jiang --- Documentation/ABI/testing/sysfs-bus-nvdimm | 3 ++- drivers/cxl/core/pmem.c | 10 ++++++---- drivers/cxl/cxl.h | 3 ++- drivers/cxl/pmem.c | 2 +- 4 files changed, 11 insertions(+), 7 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-bus-nvdimm b/Documentation/ABI/testing/sysfs-bus-nvdimm index 64eb8f4c6a41..46dafd8482b9 100644 --- a/Documentation/ABI/testing/sysfs-bus-nvdimm +++ b/Documentation/ABI/testing/sysfs-bus-nvdimm @@ -48,7 +48,8 @@ What: /sys/bus/nd/devices/nmemX/cxl/id Date: November 2022 KernelVersion: 6.2 Contact: Dave Jiang -Description: (RO) Show the id (serial) of the device. This is CXL specific. +Description: (RO) Show the id (serial) of the device, formatted as an + unsigned 64-bit decimal value. This is CXL specific. What: /sys/bus/nd/devices/nmemX/cxl/provider Date: November 2022 diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c index 68462e38a977..5a3bb7e8a1f1 100644 --- a/drivers/cxl/core/pmem.c +++ b/drivers/cxl/core/pmem.c @@ -219,12 +219,14 @@ static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_nvdimm_bridge *cxl_nvb, dev->bus = &cxl_bus_type; dev->type = &cxl_nvdimm_type; /* - * A "%llx" string is 17-bytes vs dimm_id that is max - * NVDIMM_KEY_DESC_LEN + * dev_id is the nvdimm dimm_id used for security key lookup. + * It must match id_show(), which emits the CXL serial as an + * unsigned decimal. A u64 decimal string is at most 20 digits + * plus NUL. */ - BUILD_BUG_ON(sizeof(cxl_nvd->dev_id) < 17 || + BUILD_BUG_ON(sizeof(cxl_nvd->dev_id) < 21 || sizeof(cxl_nvd->dev_id) > NVDIMM_KEY_DESC_LEN); - sprintf(cxl_nvd->dev_id, "%llx", cxlmd->cxlds->serial); + sprintf(cxl_nvd->dev_id, "%llu", cxlmd->cxlds->serial); return cxl_nvd; } diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index c0e5308e4d1b..d683ae5e0f7d 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -503,7 +503,8 @@ struct cxl_nvdimm_bridge { struct nvdimm_bus_descriptor nd_desc; }; -#define CXL_DEV_ID_LEN 19 +/* Holds a u64 serial as a decimal string: up to 20 digits + NUL */ +#define CXL_DEV_ID_LEN 21 enum { CXL_NVD_F_INVALIDATED = 0, diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c index 261dff7ced9f..a9f50281875d 100644 --- a/drivers/cxl/pmem.c +++ b/drivers/cxl/pmem.c @@ -52,7 +52,7 @@ static ssize_t id_show(struct device *dev, struct device_attribute *attr, char * struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm); struct cxl_dev_state *cxlds = cxl_nvd->cxlmd->cxlds; - return sysfs_emit(buf, "%lld\n", cxlds->serial); + return sysfs_emit(buf, "%llu\n", cxlds->serial); } static DEVICE_ATTR_RO(id); From 95a84b7cb4bbc5bd929adc9b1cd1282fca737662 Mon Sep 17 00:00:00 2001 From: Alison Schofield Date: Fri, 24 Jul 2026 13:37:18 -0700 Subject: [PATCH 2/3] cxl/core: Format the memdev serial number as unsigned in TP_printk The CXL memdev serial number is a u64 PCIe Device Serial Number, but the tracepoints format it with %lld. Devices whose vendor OUI sets bit 63 therefore appear with negative serial numbers in formatted trace output. Note that the trace data itself is already stored correctly as u64. Format the TP_printk serial as unsigned decimal, %llu, to match the underlying value. Signed-off-by: Alison Schofield Link: https://patch.msgid.link/46651395b6c1e552ae2c4fecf3058a062eb0c3f0.1784924949.git.alison.schofield@intel.com Signed-off-by: Dave Jiang --- drivers/cxl/core/trace.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h index d37876096dd7..c379d60047fc 100644 --- a/drivers/cxl/core/trace.h +++ b/drivers/cxl/core/trace.h @@ -107,7 +107,7 @@ TRACE_EVENT(cxl_aer_uncorrectable_error, memcpy(__entry->header_log, hl, CXL_HEADERLOG_TRACE_SIZE_U32 * sizeof(u32)); ), - TP_printk("memdev=%s host=%s serial=%lld: status: '%s' first_error: '%s'", + TP_printk("memdev=%s host=%s serial=%llu: status: '%s' first_error: '%s'", __get_str(memdev), __get_str(host), __entry->serial, show_uc_errs(__entry->status), show_uc_errs(__entry->first_error) @@ -166,7 +166,7 @@ TRACE_EVENT(cxl_aer_correctable_error, __entry->serial = cxlmd->cxlds->serial; __entry->status = status; ), - TP_printk("memdev=%s host=%s serial=%lld: status: '%s'", + TP_printk("memdev=%s host=%s serial=%llu: status: '%s'", __get_str(memdev), __get_str(host), __entry->serial, show_ce_errs(__entry->status) ) @@ -206,7 +206,7 @@ TRACE_EVENT(cxl_overflow, __entry->last_ts = le64_to_cpu(payload->last_overflow_timestamp); ), - TP_printk("memdev=%s host=%s serial=%lld: log=%s : %u records from %llu to %llu", + TP_printk("memdev=%s host=%s serial=%llu: log=%s : %u records from %llu to %llu", __get_str(memdev), __get_str(host), __entry->serial, cxl_event_log_type_str(__entry->log), __entry->count, __entry->first_ts, __entry->last_ts) @@ -279,7 +279,7 @@ TRACE_EVENT(cxl_overflow, __entry->hdr_head_id = (hdr).head_id #define CXL_EVT_TP_printk(fmt, ...) \ - TP_printk("memdev=%s host=%s serial=%lld log=%s : time=%llu uuid=%pUb " \ + TP_printk("memdev=%s host=%s serial=%llu log=%s : time=%llu uuid=%pUb " \ "len=%d flags='%s' handle=%x related_handle=%x " \ "maint_op_class=%u maint_op_sub_class=%u " \ "ld_id=%x head_id=%x : " fmt, \ @@ -1088,7 +1088,7 @@ TRACE_EVENT(cxl_poison, } ), - TP_printk("memdev=%s host=%s serial=%lld trace_type=%s region=%s " \ + TP_printk("memdev=%s host=%s serial=%llu trace_type=%s region=%s " \ "region_uuid=%pU hpa=0x%llx hpa_alias0=0x%llx dpa=0x%llx " \ "dpa_length=0x%x source=%s flags=%s overflow_time=%llu", __get_str(memdev), From 94d84e3d89594f6ad6dc5ed5bed05956bf146149 Mon Sep 17 00:00:00 2001 From: Alison Schofield Date: Fri, 24 Jul 2026 13:37:19 -0700 Subject: [PATCH 3/3] cxl/test: Assign one mock memdev a full-width serial number Mock memdev serial numbers have historically been derived from pdev->id, leaving them single-digit. As a result they never exercised either the decimal-vs-hex security-key lookup or unsigned formatting of large serial numbers. Give one mock memdev a full-width serial with bit 63 set. This mirrors real hardware (for example, Montage devices) and provides a test device that exposes both the hexadecimal-vs-decimal and signed-vs- unsigned formatting differences. pdev->id 7 is unused by the auto-region topology so the larger serial does not affect existing tests. This enables adding a new test case to cxl-security.sh that verify auto-unlock using a mock device whose serial exposes both formatting differences. Signed-off-by: Alison Schofield Link: https://patch.msgid.link/3e569a748fce4424b8622032fbffc298d92153b9.1784924949.git.alison.schofield@intel.com Signed-off-by: Dave Jiang --- tools/testing/cxl/test/mem.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c index a7da279aa3ef..7b756000a1a6 100644 --- a/tools/testing/cxl/test/mem.c +++ b/tools/testing/cxl/test/mem.c @@ -1713,6 +1713,7 @@ static int cxl_mock_mem_probe(struct platform_device *pdev) struct cxl_mockmem_data *mdata; struct cxl_mailbox *cxl_mbox; struct cxl_dpa_info range_info = { 0 }; + u64 serial; int rc; /* Increase async probe race window */ @@ -1739,7 +1740,19 @@ static int cxl_mock_mem_probe(struct platform_device *pdev) if (rc) return rc; - mds = cxl_memdev_state_create(dev, pdev->id + 1, 0); + /* + * Mock serials have historically been derived from pdev->id and stayed + * single-digit, so they never exercised either decimal-vs-hex key + * lookup or unsigned formatting. Give one mock device a full-width + * serial with bit 63 set, matching real hardware such as Montage CXL + * devices. pdev->id 7 is unused by the auto-region topology. + */ + if (pdev->id == 7) + serial = 0x8a34567890abcdef; + else + serial = pdev->id + 1; + + mds = cxl_memdev_state_create(dev, serial, 0); if (IS_ERR(mds)) return PTR_ERR(mds);