[PATCH v2 0/3] cxl: Format the device serial number as unsigned

[PATCH v2 0/3] cxl: Format the device serial number as unsigned

[Alison Schofield]

This series supersedes the previously posted standalone fix:
  cxl/pmem: Format nvdimm serial number as decimal

That patch addressed the immediate auto-unlock failure caused by the
kernel formatting the nvdimm security key description differently than
the decimal 'id' sysfs attribute used by ndctl.

Further review uncovered a second formatting issue affecting the same
serial number. The CXL device serial number is a u64 PCIe Device Serial
Number, yet several kernel interfaces format it with signed "%lld".
Devices whose vendor OUI sets bit 63 therefore appear with negative
decimal serial numbers.

Serials with bit 64 set are expected. The most significant byte of the
PCIe Device Serial Number contains the vendor OUI, so vendors such as
Montage naturally produce serial numbers with bit 63 set.

Rather than merge the decimal-format fix and immediately follow it with
another patch changing the same code to "%llu", fold both fixes into a
single series that consistently formats CXL serial numbers as unsigned
where appropriate and adds cxl_test coverage for the large serial case.


Alison Schofield (3):
  cxl/pmem: Format the nvdimm serial number as unsigned decimal
  cxl/core: Format the memdev serial number as unsigned in TP_printk
  cxl/test: Assign one mock memdev a full-width serial number

 Documentation/ABI/testing/sysfs-bus-nvdimm |  3 ++-
 drivers/cxl/core/pmem.c                    | 10 ++++++----
 drivers/cxl/core/trace.h                   | 10 +++++-----
 drivers/cxl/cxl.h                          |  3 ++-
 drivers/cxl/pmem.c                         |  2 +-
 tools/testing/cxl/test/mem.c               | 15 ++++++++++++++-
 6 files changed, 30 insertions(+), 13 deletions(-)


base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
-- 
2.37.3

[PATCH v2 1/3] cxl/pmem: Format the nvdimm serial number as unsigned decimal

[Alison Schofield]

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.

Cc: <stable@vger.kernel.org>
Fixes: b5807c80b5bc ("cxl: add dimm_id support for __nvdimm_create()")
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 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 <dave.jiang@intel.com>
-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);
 
-- 
2.37.3

Re: [PATCH v2 1/3] cxl/pmem: Format the nvdimm serial number as unsigned decimal

[Richard Cheng]

On Wed, Jul 01, 2026 at 05:30:44PM +0800, Alison Schofield wrote:
> 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.
> 
> Cc: <stable@vger.kernel.org>
> Fixes: b5807c80b5bc ("cxl: add dimm_id support for __nvdimm_create()")
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> ---
>  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 <dave.jiang@intel.com>
> -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);
> 

Hi Alison,

How should existing keys for high-bit serial numbers be migrated?

This patch changes both the sysfs  ID and kernel key description to unsigned
decimal. ndctl persists the old sysfs string in the key-blob filename and reloads it unchanged.

I wonder how's the old key being migrated ? I don't think the patch rename files under /etc/ndctl/keys , so ndctl may reload the existing secret
while the new kernel searches for the positive new label.

--Richard
 
>  	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);
>  
> -- 
> 2.37.3
> 
> 

Re: [PATCH v2 1/3] cxl/pmem: Format the nvdimm serial number as unsigned decimal

[Alison Schofield]

On Fri, Jul 03, 2026 at 02:28:25PM +0800, Richard Cheng wrote:
> On Wed, Jul 01, 2026 at 05:30:44PM +0800, Alison Schofield wrote:
> > 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.
> > 
> > Cc: <stable@vger.kernel.org>
> > Fixes: b5807c80b5bc ("cxl: add dimm_id support for __nvdimm_create()")
> > Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> > ---
> >  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 <dave.jiang@intel.com>
> > -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);
> > 
> 
> Hi Alison,
> 
> How should existing keys for high-bit serial numbers be migrated?
> 
> This patch changes both the sysfs  ID and kernel key description to unsigned
> decimal. ndctl persists the old sysfs string in the key-blob filename and reloads it unchanged.
> 
> I wonder how's the old key being migrated ? I don't think the patch rename files under /etc/ndctl/keys , so ndctl may reload the existing secret
> while the new kernel searches for the positive new label.

Thanks for the review. I want to add this case to the documented work-
around. I think that the exposure of this issue is very low because
of the lack of CXL pmem out in the wild. Let me know if you had other
thoughts on that belief, becuase that is what drivers me towards
documenting only, and not supply a command or script within the
ndctl tooling to do the migration.

So, only one class of key actually needs action on upgrade: a serial with
bit 63 set, which was saved under a negative-decimal description and
is now requested as unsigned decimal. Serials >= 10 without bit 63 set
never auto-unlocked on the old kernel (the original bug) and are already
named by the positive decimal the fixed kernel requests, so they need no
action.

The one-time re-stage for the bit-63 case is documented  in the work-
around now. Appending that here for reference.


CXL nvdimm auto-unlock: serial-number key-description mismatch
==============================================================

A passphrase-protected CXL nvdimm may fail to auto-unlock after a reboot,
staying "locked" so that the pmem namespaces it backs do not come up. The
cause is a serial-number formatting mismatch between the kernel and ndctl:
the kernel looked the security key up by a hex-formatted serial, while
ndctl saved and named the key blob by the decimal serial. The two spellings
differ for any serial of 10 or greater, so the key the kernel requests is
never found. A second formatting problem affects serials with bit 63 set
(for example Montage devices): the decimal serial was formatted as signed,
so it rendered as a negative value.

This is fixed in Linux 7.3 and later, which format the serial as unsigned
decimal consistently in both the key description and the 'id' attribute.
See commit <TBD-COMMIT> ("cxl/pmem: Format the nvdimm serial number as
unsigned decimal").

This document covers two situations:

- Recovering a dimm on a kernel that still lacks the fix.
- Migrating an already-enrolled key after upgrading to the fixed kernel.


Manual recovery (kernel that lacks the fix)
-------------------------------------------

If a passphrase-protected CXL nvdimm does not auto-unlock after a reboot
-- it stays "locked" and the pmem namespaces it backs do not come up --
use the following to recover on a kernel that lacks the serial fix.

1. Confirm the device is actually locked, and that auto-unlock is what
   failed (not, say, a missing key blob or a hardware/security state
   issue):

     ndctl list -i -d nmemX | jq -r '.[].dimms[0].security'

   This should report "locked". If it reports "disabled" the device has
   no passphrase enrolled and this is a different problem; if it reports
   "unlocked" there is nothing to recover.

2. Confirm the failure is the serial-number format mismatch. The kernel
   looks the key up by a hex-formatted serial, while ndctl saved and
   named it by the decimal serial. They differ for any serial of 10 or
   greater. Compare the two spellings of this device's serial:

     # decimal serial, as ndctl named the key:
     cat /sys/bus/nd/devices/nmemX/cxl/id

     # hex serial, as the kernel looks it up:
     cat /sys/bus/cxl/devices/memY/serial

   If the decimal 'id' is 10 or greater (the hex and decimal forms are
   not the same string), you are hitting this issue. Confirm the key
   blob ndctl saved exists, named by the decimal serial:

     id=$(cat /sys/bus/nd/devices/nmemX/cxl/id)
     ls /etc/ndctl/keys/nvdimm_${id}_$(hostname).blob

   If that blob is missing, the key was never saved and this recovery
   does not apply -- re-enroll the passphrase instead.

3. Stage the same key blob under the hex-formatted serial so that
   load-keys also installs the key the kernel asks for:

     id=$(cat /sys/bus/nd/devices/nmemX/cxl/id)
     hexid=$(printf '%x' "$id")
     host=$(hostname)
     cp /etc/ndctl/keys/nvdimm_${id}_${host}.blob \
        /etc/ndctl/keys/nvdimm_${hexid}_${host}.blob

4. Reload the keys and bring the device up. load-keys derives the key
   description from the blob file name, so the copy is installed as the
   nvdimm:<hex> key the kernel requests:

     ndctl load-keys
     ndctl enable-dimm nmemX

   The device should now report "unlocked":

     ndctl list -i -d nmemX | jq -r '.[].dimms[0].security'

Verified against cxl_test on an unpatched kernel: the dimm unlocks.


Migration after upgrading to the fixed kernel
---------------------------------------------

The recovery above is for a kernel that lacks the fix. After upgrading
to the fixed kernel, one class of already-enrolled key must be migrated.

The fix formats the serial as unsigned decimal (%llu) for both the key
description and the 'id' attribute. The only keys affected on upgrade are
those for a serial with bit 63 set (for example a Montage device): before
the fix id_show() emitted the serial as signed decimal, so ndctl named
the key blob by a negative string, while the fixed kernel now requests
the key by the unsigned decimal. The existing blob is not found and the
dimm fails to auto-unlock.

Serials without bit 63 set need no action. ndctl already named the blob
by the positive decimal the fixed kernel now requests, so they
auto-unlock after the upgrade with no migration.

To migrate a bit-63 serial, stage the existing blob under the unsigned
decimal name the fixed kernel requests. The old blob is already on disk
named by the negative decimal the previous kernel emitted, so locate it
rather than recompute it:

     # unsigned decimal serial, as the fixed kernel now looks it up:
     id=$(cat /sys/bus/nd/devices/nmemX/cxl/id)
     host=$(hostname)

     # the existing blob, named by the old negative decimal:
     ls /etc/ndctl/keys/nvdimm_-*_${host}.blob

     cp /etc/ndctl/keys/nvdimm_<negative-id>_${host}.blob \
        /etc/ndctl/keys/nvdimm_${id}_${host}.blob

Reload the keys and bring the device up. load-keys derives the key
description from the blob file name, so the copy is installed as the
nvdimm:<unsigned-decimal> key the fixed kernel requests:

     ndctl load-keys
     ndctl enable-dimm nmemX

   The device should now report "unlocked":

     ndctl list -i -d nmemX | jq -r '.[].dimms[0].security'



> 
> --Richard
>  
> >  	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);
> >  
> > -- 
> > 2.37.3
> > 
> > 
> 

[PATCH v2 2/3] cxl/core: Format the memdev serial number as unsigned in TP_printk

[Alison Schofield]

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 <alison.schofield@intel.com>
---
 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),
-- 
2.37.3

[PATCH v2 3/3] cxl/test: Assign one mock memdev a full-width serial number

[Alison Schofield]

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.

This enables adding a new test case to cxl-security.sh that does an
auto-unlock using a mock device whose serial exposes both formatting
differences.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 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 a1d170f88fee..42f5ffd29651 100644
--- a/tools/testing/cxl/test/mem.c
+++ b/tools/testing/cxl/test/mem.c
@@ -1714,6 +1714,7 @@ 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 */
@@ -1740,7 +1741,19 @@ 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);
 
-- 
2.37.3