[PATCH net-next 0/3] psp: add crypt-offset and spi-threshold attributes

[PATCH net-next 0/3] psp: add crypt-offset and spi-threshold attributes

[Akhilesh Samineni]

This series introduces two new configurable per-device attributes to
the PSP (PSP Security Protocol) subsystem: crypt-offset and spi-threshold.

crypt-offset (Crypt Offset)
----------------------------------
The crypt-offset attribute specifies the byte offset within a packet from
which encryption begins. A non-zero value allows a fixed-size portion of
the packet header to remain in plaintext, which is useful where
intermediate network nodes need to inspect a well-known header before the
encrypted region. The default value is 0, meaning encryption starts
immediately after the PSP header.

spi-threshold (SPI Threshold)
-------------------------------
SPI values are allocated monotonically from a 32-bit per-device space.
The spi-threshold attribute lets userspace configure the SPI value at
which rotation should be triggered before the space is exhausted.

A named constant PSP_SPI_THRESHOLD_DEFAULT (~90% of 0x7FFFFFFF) is
introduced in include/net/psp/types.h as the single authoritative
definition, used by both the PSP core (psp_main.c) and the netdevsim
driver (psp.c). This avoids scattering the magic value across drivers.

A follow-up series will add netlink notification support to alert
subscribed listeners when the configured spi-threshold is reached,
enabling timely SPI rotation.

Akhilesh Samineni (3):
  psp: add crypt-offset and spi-threshold get/set attributes
  netdevsim: psp: handle the new crypt-offset and spi-threshold get/set operations
  selftests: net: psp: add crypt-offset and spi-threshold test cases

 Documentation/netlink/specs/psp.yaml       | 13 +++++++++
 drivers/net/netdevsim/netdevsim.h          |  2 ++
 drivers/net/netdevsim/psp.c                |  6 ++++
 include/net/psp/types.h                    |  7 +++++
 include/uapi/linux/psp.h                   |  2 ++
 net/psp/psp-nl-gen.c                       |  6 ++--
 net/psp/psp_main.c                         |  3 ++
 net/psp/psp_nl.c                           | 27 +++++++++++++++---
 tools/testing/selftests/drivers/net/psp.py | 32 +++++++++++++++++++++++
 9 files changed, 92 insertions(+), 6 deletions(-)

-- 
2.45.4

[PATCH net-next 1/3] psp: add crypt-offset and spi-threshold get/set attributes

[Akhilesh Samineni]

crypt-offset (Crypt Offset)
----------------------------------
The crypt-offset attribute specifies the byte offset within a packet
from which encryption begins. This is a per-device attribute that
allows a portion of the packet header to remain in plaintext while
the rest of the payload is encrypted. This is useful in scenarios
where intermediate nodes need to inspect or process a fixed-size
header before the encrypted payload.

The default value is 0, meaning encryption starts from the beginning
of the payload following the PSP header.

spi-threshold (SPI Threshold)
------------------------------
The SPI (Security Parameter Index) is a 32-bit per-device identifier
used to distinguish security associations. As SPI values are allocated
monotonically, a threshold is needed to trigger timely SPI rotation
before the space is exhausted.

The spi-threshold attribute allows userspace to configure the value at
which an SPI rotation should be initiated. The default is set to
PSP_SPI_THRESHOLD_DEFAULT (~90% of 0x7FFFFFFF), providing a comfortable
margin to perform rotation without racing to exhaustion.

NOTE: A follow-up series will add notification support to alert
subscribed users when the configured spi-threshold is reached, enabling
timely SPI rotation.

Signed-off-by: Akhilesh Samineni <akhilesh.samineni@broadcom.com>
Reviewed-by: Kiran Kella <kiran.kella@broadcom.com>
Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>
---
 Documentation/netlink/specs/psp.yaml | 13 +++++++++++++
 include/net/psp/types.h              |  7 +++++++
 include/uapi/linux/psp.h             |  2 ++
 net/psp/psp-nl-gen.c                 |  6 ++++--
 net/psp/psp_main.c                   |  3 +++
 net/psp/psp_nl.c                     | 27 +++++++++++++++++++++++----
 6 files changed, 52 insertions(+), 6 deletions(-)

diff --git a/Documentation/netlink/specs/psp.yaml b/Documentation/netlink/specs/psp.yaml
index f3a57782d2cf..b22869be91cf 100644
--- a/Documentation/netlink/specs/psp.yaml
+++ b/Documentation/netlink/specs/psp.yaml
@@ -38,6 +38,15 @@ attribute-sets:
         type: u32
         enum: version
         enum-as-flags: true
+      -
+        name: crypt-offset
+        doc: The offset from the end of the PSP header to the start of the encrypted payload.
+        type: u8
+      -
+        name: spi-threshold
+        doc: Threshold for the SPI to trigger notification to the user for appropriate rotate action.
+        type: u32
+
   -
     name: assoc
     attributes:
@@ -170,6 +179,8 @@ operations:
             - ifindex
             - psp-versions-cap
             - psp-versions-ena
+            - crypt-offset
+            - spi-threshold
         pre: psp-device-get-locked
         post: psp-device-unlock
       dump:
@@ -193,6 +204,8 @@ operations:
           attributes:
             - id
             - psp-versions-ena
+            - crypt-offset
+            - spi-threshold
         reply:
           attributes: []
         pre: psp-device-get-locked
diff --git a/include/net/psp/types.h b/include/net/psp/types.h
index 25a9096d4e7d..875f7822557f 100644
--- a/include/net/psp/types.h
+++ b/include/net/psp/types.h
@@ -25,6 +25,9 @@ struct psphdr {
 #define PSP_SPI_KEY_ID		GENMASK(30, 0)
 #define PSP_SPI_KEY_PHASE	BIT(31)
 
+/* Default SPI threshold: ~90% of max SPI (0x7FFFFFFF) to allow rotation before exhaustion */
+#define PSP_SPI_THRESHOLD_DEFAULT	0x73333333
+
 #define PSPHDR_CRYPT_OFFSET	GENMASK(5, 0)
 
 #define PSPHDR_VERFL_SAMPLE	BIT(7)
@@ -38,9 +41,13 @@ struct psphdr {
 /**
  * struct psp_dev_config - PSP device configuration
  * @versions: PSP versions enabled on the device
+ * @crypt_offset: crypto offset configured on the device
+ * @spi_threshold: SPI threshold value on the device
  */
 struct psp_dev_config {
 	u32 versions;
+	u8 crypt_offset;
+	u32 spi_threshold;
 };
 
 /**
diff --git a/include/uapi/linux/psp.h b/include/uapi/linux/psp.h
index a3a336488dc3..bb390159dc72 100644
--- a/include/uapi/linux/psp.h
+++ b/include/uapi/linux/psp.h
@@ -22,6 +22,8 @@ enum {
 	PSP_A_DEV_IFINDEX,
 	PSP_A_DEV_PSP_VERSIONS_CAP,
 	PSP_A_DEV_PSP_VERSIONS_ENA,
+	PSP_A_DEV_CRYPT_OFFSET,
+	PSP_A_DEV_SPI_THRESHOLD,
 
 	__PSP_A_DEV_MAX,
 	PSP_A_DEV_MAX = (__PSP_A_DEV_MAX - 1)
diff --git a/net/psp/psp-nl-gen.c b/net/psp/psp-nl-gen.c
index 22a48d0fa378..e50b8b80955c 100644
--- a/net/psp/psp-nl-gen.c
+++ b/net/psp/psp-nl-gen.c
@@ -23,9 +23,11 @@ static const struct nla_policy psp_dev_get_nl_policy[PSP_A_DEV_ID + 1] = {
 };
 
 /* PSP_CMD_DEV_SET - do */
-static const struct nla_policy psp_dev_set_nl_policy[PSP_A_DEV_PSP_VERSIONS_ENA + 1] = {
+static const struct nla_policy psp_dev_set_nl_policy[PSP_A_DEV_SPI_THRESHOLD + 1] = {
 	[PSP_A_DEV_ID] = NLA_POLICY_MIN(NLA_U32, 1),
 	[PSP_A_DEV_PSP_VERSIONS_ENA] = NLA_POLICY_MASK(NLA_U32, 0xf),
+	[PSP_A_DEV_CRYPT_OFFSET] = { .type = NLA_U8, },
+	[PSP_A_DEV_SPI_THRESHOLD] = { .type = NLA_U32, },
 };
 
 /* PSP_CMD_KEY_ROTATE - do */
@@ -75,7 +77,7 @@ static const struct genl_split_ops psp_nl_ops[] = {
 		.doit		= psp_nl_dev_set_doit,
 		.post_doit	= psp_device_unlock,
 		.policy		= psp_dev_set_nl_policy,
-		.maxattr	= PSP_A_DEV_PSP_VERSIONS_ENA,
+		.maxattr	= PSP_A_DEV_SPI_THRESHOLD,
 		.flags		= GENL_CMD_CAP_DO,
 	},
 	{
diff --git a/net/psp/psp_main.c b/net/psp/psp_main.c
index 9508b6c38003..536ee44db09d 100644
--- a/net/psp/psp_main.c
+++ b/net/psp/psp_main.c
@@ -79,6 +79,9 @@ psp_dev_create(struct net_device *netdev,
 	INIT_LIST_HEAD(&psd->stale_assocs);
 	refcount_set(&psd->refcnt, 1);
 
+	/* ~90% of 0x7FFFFFFF; allows SPI rotation well before space is exhausted */
+	psd->config.spi_threshold = PSP_SPI_THRESHOLD_DEFAULT;
+
 	mutex_lock(&psp_devs_lock);
 	err = xa_alloc_cyclic(&psp_devs, &psd->id, psd, xa_limit_16b,
 			      &last_id, GFP_KERNEL);
diff --git a/net/psp/psp_nl.c b/net/psp/psp_nl.c
index 6afd7707ec12..fbb77460a24b 100644
--- a/net/psp/psp_nl.c
+++ b/net/psp/psp_nl.c
@@ -101,7 +101,9 @@ psp_nl_dev_fill(struct psp_dev *psd, struct sk_buff *rsp,
 	if (nla_put_u32(rsp, PSP_A_DEV_ID, psd->id) ||
 	    nla_put_u32(rsp, PSP_A_DEV_IFINDEX, psd->main_netdev->ifindex) ||
 	    nla_put_u32(rsp, PSP_A_DEV_PSP_VERSIONS_CAP, psd->caps->versions) ||
-	    nla_put_u32(rsp, PSP_A_DEV_PSP_VERSIONS_ENA, psd->config.versions))
+	    nla_put_u32(rsp, PSP_A_DEV_PSP_VERSIONS_ENA, psd->config.versions) ||
+	    nla_put_u8(rsp, PSP_A_DEV_CRYPT_OFFSET, psd->config.crypt_offset) ||
+	    nla_put_u32(rsp, PSP_A_DEV_SPI_THRESHOLD, psd->config.spi_threshold))
 		goto err_cancel_msg;
 
 	genlmsg_end(rsp, hdr);
@@ -193,6 +195,13 @@ int psp_nl_dev_set_doit(struct sk_buff *skb, struct genl_info *info)
 
 	memcpy(&new_config, &psd->config, sizeof(new_config));
 
+	if (!info->attrs[PSP_A_DEV_PSP_VERSIONS_ENA] &&
+	    !info->attrs[PSP_A_DEV_CRYPT_OFFSET] &&
+	    !info->attrs[PSP_A_DEV_SPI_THRESHOLD]) {
+		NL_SET_ERR_MSG(info->extack, "No settings present");
+		return -EINVAL;
+	}
+
 	if (info->attrs[PSP_A_DEV_PSP_VERSIONS_ENA]) {
 		new_config.versions =
 			nla_get_u32(info->attrs[PSP_A_DEV_PSP_VERSIONS_ENA]);
@@ -200,9 +209,19 @@ int psp_nl_dev_set_doit(struct sk_buff *skb, struct genl_info *info)
 			NL_SET_ERR_MSG(info->extack, "Requested PSP versions not supported by the device");
 			return -EINVAL;
 		}
-	} else {
-		NL_SET_ERR_MSG(info->extack, "No settings present");
-		return -EINVAL;
+	}
+
+	if (info->attrs[PSP_A_DEV_CRYPT_OFFSET])
+		new_config.crypt_offset =
+			nla_get_u8(info->attrs[PSP_A_DEV_CRYPT_OFFSET]);
+
+	if (info->attrs[PSP_A_DEV_SPI_THRESHOLD]) {
+		new_config.spi_threshold =
+			nla_get_u32(info->attrs[PSP_A_DEV_SPI_THRESHOLD]);
+		if (new_config.spi_threshold & PSP_SPI_KEY_PHASE) {
+			NL_SET_ERR_MSG(info->extack, "SPI threshold must not have bit 31 set");
+			return -EINVAL;
+		}
 	}
 
 	rsp = psp_nl_reply_new(info);
-- 
2.45.4

[PATCH net-next 2/3] netdevsim: psp: handle the new crypt-offset and spi-threshold get/set operations

[Akhilesh Samineni]

Implement the crypt-offset and spi-threshold get/set in netdevsim PSP.

Signed-off-by: Akhilesh Samineni <akhilesh.samineni@broadcom.com>
Reviewed-by: Kiran Kella <kiran.kella@broadcom.com>
Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>
---
 drivers/net/netdevsim/netdevsim.h | 2 ++
 drivers/net/netdevsim/psp.c       | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index c904e14f6b3f..3ad7d42391c0 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -117,6 +117,8 @@ struct netdevsim {
 		struct psp_dev *dev;
 		u32 spi;
 		u32 assoc_cnt;
+		u8  crypt_offset;
+		u32 spi_threshold;
 	} psp;
 
 	struct nsim_bus_dev *nsim_bus_dev;
diff --git a/drivers/net/netdevsim/psp.c b/drivers/net/netdevsim/psp.c
index 0b4d717253b0..9098edf00c5c 100644
--- a/drivers/net/netdevsim/psp.c
+++ b/drivers/net/netdevsim/psp.c
@@ -122,6 +122,11 @@ static int
 nsim_psp_set_config(struct psp_dev *psd, struct psp_dev_config *conf,
 		    struct netlink_ext_ack *extack)
 {
+	struct netdevsim *ns = psd->drv_priv;
+
+	ns->psp.crypt_offset = conf->crypt_offset;
+	ns->psp.spi_threshold = conf->spi_threshold;
+
 	return 0;
 }
 
@@ -249,6 +254,7 @@ int nsim_psp_init(struct netdevsim *ns)
 	if (err)
 		return err;
 
+	ns->psp.spi_threshold = PSP_SPI_THRESHOLD_DEFAULT;
 	debugfs_create_file("psp_rereg", 0200, ddir, ns, &nsim_psp_rereg_fops);
 	return 0;
 }
-- 
2.45.4

[PATCH net-next 3/3] selftests: net: psp: add crypt-offset and spi-threshold test cases

[Akhilesh Samineni]

Add test cases to set and get crypt-offset and spi-threshold attributes,
verifying both the applied value and the restored prior value.

Signed-off-by: Akhilesh Samineni <akhilesh.samineni@broadcom.com>
Reviewed-by: Kiran Kella <kiran.kella@broadcom.com>
Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>
---
 tools/testing/selftests/drivers/net/psp.py | 32 ++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/tools/testing/selftests/drivers/net/psp.py b/tools/testing/selftests/drivers/net/psp.py
index 864d9fce1094..9253aab29ded 100755
--- a/tools/testing/selftests/drivers/net/psp.py
+++ b/tools/testing/selftests/drivers/net/psp.py
@@ -171,6 +171,38 @@ def dev_get_device_bad(cfg):
     ksft_true(raised)
 
 
+def dev_set_crypt_offset(cfg):
+    """ Set and get the crypt-offset """
+    _init_psp_dev(cfg)
+
+    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
+    orig = dev['crypt-offset']
+    cfg.pspnl.dev_set({"id": cfg.psp_dev_id,
+                       "crypt-offset": 5})
+    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
+    ksft_eq(dev['crypt-offset'], 5)
+    cfg.pspnl.dev_set({"id": cfg.psp_dev_id,
+                       "crypt-offset": orig})
+    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
+    ksft_eq(dev['crypt-offset'], orig)
+
+
+def dev_set_spi_threshold(cfg):
+    """ Set and get the spi-threshold """
+    _init_psp_dev(cfg)
+
+    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
+    orig = dev['spi-threshold']
+    cfg.pspnl.dev_set({"id": cfg.psp_dev_id,
+                       "spi-threshold": 10})
+    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
+    ksft_eq(dev['spi-threshold'], 10)
+    cfg.pspnl.dev_set({"id": cfg.psp_dev_id,
+                       "spi-threshold": orig})
+    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
+    ksft_eq(dev['spi-threshold'], orig)
+
+
 def dev_rotate(cfg):
     """ Test key rotation """
     _init_psp_dev(cfg)
-- 
2.45.4

Re: [PATCH net-next 0/3] psp: add crypt-offset and spi-threshold attributes

[Jakub Kicinski]

On Mon,  6 Apr 2026 15:23:02 -0700 Akhilesh Samineni wrote:
> This series introduces two new configurable per-device attributes to
> the PSP (PSP Security Protocol) subsystem: crypt-offset and spi-threshold.

Please read this document:
https://www.kernel.org/doc/html/next/process/maintainer-netdev.html
-- 
pw-bot: cr

Re: [PATCH net-next 0/3] psp: add crypt-offset and spi-threshold attributes

[Akhilesh Samineni]

[-- Attachment #1: Type: text/plain, Size: 577 bytes --]

On Tue, Apr 7, 2026 at 6:44 AM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Mon,  6 Apr 2026 15:23:02 -0700 Akhilesh Samineni wrote:
> > This series introduces two new configurable per-device attributes to
> > the PSP (PSP Security Protocol) subsystem: crypt-offset and spi-threshold.
>
> Please read this document:
> https://www.kernel.org/doc/html/next/process/maintainer-netdev.html
> --

Thank you for the link. I have reviewed the netdev process documentation.
I’ve ensured my patches pass checkpatch and include the correct maintainers.

> pw-bot: cr

[-- Attachment #2: S/MIME Cryptographic Signature --]
[-- Type: application/pkcs7-signature, Size: 4211 bytes --]

Re: [PATCH net-next 0/3] psp: add crypt-offset and spi-threshold attributes

[Daniel Zahka]

On 4/7/26 11:39 AM, Akhilesh Samineni wrote:
> On Tue, Apr 7, 2026 at 6:44 AM Jakub Kicinski <kuba@kernel.org> wrote:
>> On Mon,  6 Apr 2026 15:23:02 -0700 Akhilesh Samineni wrote:
>>> This series introduces two new configurable per-device attributes to
>>> the PSP (PSP Security Protocol) subsystem: crypt-offset and spi-threshold.
>> Please read this document:
>> https://www.kernel.org/doc/html/next/process/maintainer-netdev.html
>> --
> Thank you for the link. I have reviewed the netdev process documentation.
> I’ve ensured my patches pass checkpatch and include the correct maintainers.


Hi Akhilesh. There's a sentence in the netdevsim section of that 
document that is problematic for the series as it is currently: 
"netdevsim in itself is not considered a use case/user. You must also 
implement the new APIs in a real driver."

Re: [PATCH net-next 1/3] psp: add crypt-offset and spi-threshold get/set attributes

[Willem de Bruijn]

Akhilesh Samineni wrote:
> crypt-offset (Crypt Offset)
> ----------------------------------
> The crypt-offset attribute specifies the byte offset within a packet
> from which encryption begins. This is a per-device attribute that
> allows a portion of the packet header to remain in plaintext while
> the rest of the payload is encrypted. This is useful in scenarios
> where intermediate nodes need to inspect or process a fixed-size
> header before the encrypted payload.
> 
> The default value is 0, meaning encryption starts from the beginning
> of the payload following the PSP header.
> 
> spi-threshold (SPI Threshold)
> ------------------------------
> The SPI (Security Parameter Index) is a 32-bit per-device identifier
> used to distinguish security associations. As SPI values are allocated
> monotonically, a threshold is needed to trigger timely SPI rotation
> before the space is exhausted.
> 
> The spi-threshold attribute allows userspace to configure the value at
> which an SPI rotation should be initiated. The default is set to
> PSP_SPI_THRESHOLD_DEFAULT (~90% of 0x7FFFFFFF), providing a comfortable
> margin to perform rotation without racing to exhaustion.
> 
> NOTE: A follow-up series will add notification support to alert
> subscribed users when the configured spi-threshold is reached, enabling
> timely SPI rotation.
> 
> Signed-off-by: Akhilesh Samineni <akhilesh.samineni@broadcom.com>
> Reviewed-by: Kiran Kella <kiran.kella@broadcom.com>
> Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>
> ---
>  Documentation/netlink/specs/psp.yaml | 13 +++++++++++++
>  include/net/psp/types.h              |  7 +++++++
>  include/uapi/linux/psp.h             |  2 ++
>  net/psp/psp-nl-gen.c                 |  6 ++++--
>  net/psp/psp_main.c                   |  3 +++
>  net/psp/psp_nl.c                     | 27 +++++++++++++++++++++++----
>  6 files changed, 52 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/netlink/specs/psp.yaml b/Documentation/netlink/specs/psp.yaml
> index f3a57782d2cf..b22869be91cf 100644
> --- a/Documentation/netlink/specs/psp.yaml
> +++ b/Documentation/netlink/specs/psp.yaml
> @@ -38,6 +38,15 @@ attribute-sets:
>          type: u32
>          enum: version
>          enum-as-flags: true
> +      -
> +        name: crypt-offset
> +        doc: The offset from the end of the PSP header to the start of the encrypted payload.

In 4 octet units?

> +        type: u8
> +      -
> +        name: spi-threshold
> +        doc: Threshold for the SPI to trigger notification to the user for appropriate rotate action.
> +        type: u32
> +
>    -
>      name: assoc
>      attributes:
> @@ -170,6 +179,8 @@ operations:
>              - ifindex
>              - psp-versions-cap
>              - psp-versions-ena
> +            - crypt-offset
> +            - spi-threshold
>          pre: psp-device-get-locked
>          post: psp-device-unlock
>        dump:
> @@ -193,6 +204,8 @@ operations:
>            attributes:
>              - id
>              - psp-versions-ena
> +            - crypt-offset
> +            - spi-threshold
>          reply:
>            attributes: []
>          pre: psp-device-get-locked
> diff --git a/include/net/psp/types.h b/include/net/psp/types.h
> index 25a9096d4e7d..875f7822557f 100644
> --- a/include/net/psp/types.h
> +++ b/include/net/psp/types.h
> @@ -25,6 +25,9 @@ struct psphdr {
>  #define PSP_SPI_KEY_ID		GENMASK(30, 0)
>  #define PSP_SPI_KEY_PHASE	BIT(31)
>  
> +/* Default SPI threshold: ~90% of max SPI (0x7FFFFFFF) to allow rotation before exhaustion */
> +#define PSP_SPI_THRESHOLD_DEFAULT	0x73333333

Do you want to choose a more round number, in either hex or dec?

> +
>  #define PSPHDR_CRYPT_OFFSET	GENMASK(5, 0)
>  
>  #define PSPHDR_VERFL_SAMPLE	BIT(7)
> @@ -38,9 +41,13 @@ struct psphdr {
>  /**
>   * struct psp_dev_config - PSP device configuration
>   * @versions: PSP versions enabled on the device
> + * @crypt_offset: crypto offset configured on the device
> + * @spi_threshold: SPI threshold value on the device
>   */
>  struct psp_dev_config {
>  	u32 versions;
> +	u8 crypt_offset;
> +	u32 spi_threshold;
>  };
>  
>  /**
> diff --git a/include/uapi/linux/psp.h b/include/uapi/linux/psp.h
> index a3a336488dc3..bb390159dc72 100644
> --- a/include/uapi/linux/psp.h
> +++ b/include/uapi/linux/psp.h
> @@ -22,6 +22,8 @@ enum {
>  	PSP_A_DEV_IFINDEX,
>  	PSP_A_DEV_PSP_VERSIONS_CAP,
>  	PSP_A_DEV_PSP_VERSIONS_ENA,
> +	PSP_A_DEV_CRYPT_OFFSET,
> +	PSP_A_DEV_SPI_THRESHOLD,
>  
>  	__PSP_A_DEV_MAX,
>  	PSP_A_DEV_MAX = (__PSP_A_DEV_MAX - 1)
> diff --git a/net/psp/psp-nl-gen.c b/net/psp/psp-nl-gen.c
> index 22a48d0fa378..e50b8b80955c 100644
> --- a/net/psp/psp-nl-gen.c
> +++ b/net/psp/psp-nl-gen.c
> @@ -23,9 +23,11 @@ static const struct nla_policy psp_dev_get_nl_policy[PSP_A_DEV_ID + 1] = {
>  };
>  
>  /* PSP_CMD_DEV_SET - do */
> -static const struct nla_policy psp_dev_set_nl_policy[PSP_A_DEV_PSP_VERSIONS_ENA + 1] = {
> +static const struct nla_policy psp_dev_set_nl_policy[PSP_A_DEV_SPI_THRESHOLD + 1] = {
>  	[PSP_A_DEV_ID] = NLA_POLICY_MIN(NLA_U32, 1),
>  	[PSP_A_DEV_PSP_VERSIONS_ENA] = NLA_POLICY_MASK(NLA_U32, 0xf),
> +	[PSP_A_DEV_CRYPT_OFFSET] = { .type = NLA_U8, },
> +	[PSP_A_DEV_SPI_THRESHOLD] = { .type = NLA_U32, },
>  };
>  
>  /* PSP_CMD_KEY_ROTATE - do */
> @@ -75,7 +77,7 @@ static const struct genl_split_ops psp_nl_ops[] = {
>  		.doit		= psp_nl_dev_set_doit,
>  		.post_doit	= psp_device_unlock,
>  		.policy		= psp_dev_set_nl_policy,
> -		.maxattr	= PSP_A_DEV_PSP_VERSIONS_ENA,
> +		.maxattr	= PSP_A_DEV_SPI_THRESHOLD,
>  		.flags		= GENL_CMD_CAP_DO,
>  	},
>  	{
> diff --git a/net/psp/psp_main.c b/net/psp/psp_main.c
> index 9508b6c38003..536ee44db09d 100644
> --- a/net/psp/psp_main.c
> +++ b/net/psp/psp_main.c
> @@ -79,6 +79,9 @@ psp_dev_create(struct net_device *netdev,
>  	INIT_LIST_HEAD(&psd->stale_assocs);
>  	refcount_set(&psd->refcnt, 1);
>  
> +	/* ~90% of 0x7FFFFFFF; allows SPI rotation well before space is exhausted */

Repeat comment. Not needed here.

> +	psd->config.spi_threshold = PSP_SPI_THRESHOLD_DEFAULT;
> +
>  	mutex_lock(&psp_devs_lock);
>  	err = xa_alloc_cyclic(&psp_devs, &psd->id, psd, xa_limit_16b,
>  			      &last_id, GFP_KERNEL);
> diff --git a/net/psp/psp_nl.c b/net/psp/psp_nl.c
> index 6afd7707ec12..fbb77460a24b 100644
> --- a/net/psp/psp_nl.c
> +++ b/net/psp/psp_nl.c
> @@ -101,7 +101,9 @@ psp_nl_dev_fill(struct psp_dev *psd, struct sk_buff *rsp,
>  	if (nla_put_u32(rsp, PSP_A_DEV_ID, psd->id) ||
>  	    nla_put_u32(rsp, PSP_A_DEV_IFINDEX, psd->main_netdev->ifindex) ||
>  	    nla_put_u32(rsp, PSP_A_DEV_PSP_VERSIONS_CAP, psd->caps->versions) ||
> -	    nla_put_u32(rsp, PSP_A_DEV_PSP_VERSIONS_ENA, psd->config.versions))
> +	    nla_put_u32(rsp, PSP_A_DEV_PSP_VERSIONS_ENA, psd->config.versions) ||
> +	    nla_put_u8(rsp, PSP_A_DEV_CRYPT_OFFSET, psd->config.crypt_offset) ||
> +	    nla_put_u32(rsp, PSP_A_DEV_SPI_THRESHOLD, psd->config.spi_threshold))
>  		goto err_cancel_msg;
>  
>  	genlmsg_end(rsp, hdr);
> @@ -193,6 +195,13 @@ int psp_nl_dev_set_doit(struct sk_buff *skb, struct genl_info *info)
>  
>  	memcpy(&new_config, &psd->config, sizeof(new_config));
>  
> +	if (!info->attrs[PSP_A_DEV_PSP_VERSIONS_ENA] &&
> +	    !info->attrs[PSP_A_DEV_CRYPT_OFFSET] &&
> +	    !info->attrs[PSP_A_DEV_SPI_THRESHOLD]) {
> +		NL_SET_ERR_MSG(info->extack, "No settings present");
> +		return -EINVAL;
> +	}
> +
>  	if (info->attrs[PSP_A_DEV_PSP_VERSIONS_ENA]) {
>  		new_config.versions =
>  			nla_get_u32(info->attrs[PSP_A_DEV_PSP_VERSIONS_ENA]);
> @@ -200,9 +209,19 @@ int psp_nl_dev_set_doit(struct sk_buff *skb, struct genl_info *info)
>  			NL_SET_ERR_MSG(info->extack, "Requested PSP versions not supported by the device");
>  			return -EINVAL;
>  		}
> -	} else {
> -		NL_SET_ERR_MSG(info->extack, "No settings present");
> -		return -EINVAL;
> +	}
> +
> +	if (info->attrs[PSP_A_DEV_CRYPT_OFFSET])
> +		new_config.crypt_offset =
> +			nla_get_u8(info->attrs[PSP_A_DEV_CRYPT_OFFSET]);

PSP defines a 6-bit field in 4 octet units. Does this need bounds checking?

> +
> +	if (info->attrs[PSP_A_DEV_SPI_THRESHOLD]) {
> +		new_config.spi_threshold =
> +			nla_get_u32(info->attrs[PSP_A_DEV_SPI_THRESHOLD]);
> +		if (new_config.spi_threshold & PSP_SPI_KEY_PHASE) {
> +			NL_SET_ERR_MSG(info->extack, "SPI threshold must not have bit 31 set");
> +			return -EINVAL;
> +		}
>  	}
>  
>  	rsp = psp_nl_reply_new(info);
> -- 
> 2.45.4
> 

Re: [PATCH net-next 2/3] netdevsim: psp: handle the new crypt-offset and spi-threshold get/set operations

[Willem de Bruijn]

Akhilesh Samineni wrote:
> Implement the crypt-offset and spi-threshold get/set in netdevsim PSP.
> 
> Signed-off-by: Akhilesh Samineni <akhilesh.samineni@broadcom.com>
> Reviewed-by: Kiran Kella <kiran.kella@broadcom.com>
> Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>
> ---
>  drivers/net/netdevsim/netdevsim.h | 2 ++
>  drivers/net/netdevsim/psp.c       | 6 ++++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
> index c904e14f6b3f..3ad7d42391c0 100644
> --- a/drivers/net/netdevsim/netdevsim.h
> +++ b/drivers/net/netdevsim/netdevsim.h
> @@ -117,6 +117,8 @@ struct netdevsim {
>  		struct psp_dev *dev;
>  		u32 spi;
>  		u32 assoc_cnt;
> +		u8  crypt_offset;

Minor: variable names are already not aligned. No need for two spaces.

> +		u32 spi_threshold;
>  	} psp;
>  
>  	struct nsim_bus_dev *nsim_bus_dev;
> diff --git a/drivers/net/netdevsim/psp.c b/drivers/net/netdevsim/psp.c
> index 0b4d717253b0..9098edf00c5c 100644
> --- a/drivers/net/netdevsim/psp.c
> +++ b/drivers/net/netdevsim/psp.c
> @@ -122,6 +122,11 @@ static int
>  nsim_psp_set_config(struct psp_dev *psd, struct psp_dev_config *conf,
>  		    struct netlink_ext_ack *extack)
>  {
> +	struct netdevsim *ns = psd->drv_priv;
> +
> +	ns->psp.crypt_offset = conf->crypt_offset;
> +	ns->psp.spi_threshold = conf->spi_threshold;
> +
>  	return 0;
>  }
>  
> @@ -249,6 +254,7 @@ int nsim_psp_init(struct netdevsim *ns)
>  	if (err)
>  		return err;
>  
> +	ns->psp.spi_threshold = PSP_SPI_THRESHOLD_DEFAULT;
>  	debugfs_create_file("psp_rereg", 0200, ddir, ns, &nsim_psp_rereg_fops);
>  	return 0;
>  }
> -- 
> 2.45.4
> 

Re: [PATCH net-next 2/3] netdevsim: psp: handle the new crypt-offset and spi-threshold get/set operations

[Willem de Bruijn]

Akhilesh Samineni wrote:
> Implement the crypt-offset and spi-threshold get/set in netdevsim PSP.
> 
> Signed-off-by: Akhilesh Samineni <akhilesh.samineni@broadcom.com>
> Reviewed-by: Kiran Kella <kiran.kella@broadcom.com>
> Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>
> ---
>  drivers/net/netdevsim/netdevsim.h | 2 ++
>  drivers/net/netdevsim/psp.c       | 6 ++++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
> index c904e14f6b3f..3ad7d42391c0 100644
> --- a/drivers/net/netdevsim/netdevsim.h
> +++ b/drivers/net/netdevsim/netdevsim.h
> @@ -117,6 +117,8 @@ struct netdevsim {
>  		struct psp_dev *dev;
>  		u32 spi;
>  		u32 assoc_cnt;
> +		u8  crypt_offset;
> +		u32 spi_threshold;
>  	} psp;
>  
>  	struct nsim_bus_dev *nsim_bus_dev;
> diff --git a/drivers/net/netdevsim/psp.c b/drivers/net/netdevsim/psp.c
> index 0b4d717253b0..9098edf00c5c 100644
> --- a/drivers/net/netdevsim/psp.c
> +++ b/drivers/net/netdevsim/psp.c
> @@ -122,6 +122,11 @@ static int
>  nsim_psp_set_config(struct psp_dev *psd, struct psp_dev_config *conf,
>  		    struct netlink_ext_ack *extack)
>  {
> +	struct netdevsim *ns = psd->drv_priv;
> +
> +	ns->psp.crypt_offset = conf->crypt_offset;
> +	ns->psp.spi_threshold = conf->spi_threshold;
> +
>  	return 0;
>  }
>  
> @@ -249,6 +254,7 @@ int nsim_psp_init(struct netdevsim *ns)
>  	if (err)
>  		return err;
>  
> +	ns->psp.spi_threshold = PSP_SPI_THRESHOLD_DEFAULT;
>  	debugfs_create_file("psp_rereg", 0200, ddir, ns, &nsim_psp_rereg_fops);
>  	return 0;

Default initialization should probably all complete before the device
is made visible with psp_dev_create.

Re: [PATCH net-next 3/3] selftests: net: psp: add crypt-offset and spi-threshold test cases

[Willem de Bruijn]

Akhilesh Samineni wrote:
> Add test cases to set and get crypt-offset and spi-threshold attributes,
> verifying both the applied value and the restored prior value.
> 
> Signed-off-by: Akhilesh Samineni <akhilesh.samineni@broadcom.com>
> Reviewed-by: Kiran Kella <kiran.kella@broadcom.com>
> Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>
> ---
>  tools/testing/selftests/drivers/net/psp.py | 32 ++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/tools/testing/selftests/drivers/net/psp.py b/tools/testing/selftests/drivers/net/psp.py
> index 864d9fce1094..9253aab29ded 100755
> --- a/tools/testing/selftests/drivers/net/psp.py
> +++ b/tools/testing/selftests/drivers/net/psp.py
> @@ -171,6 +171,38 @@ def dev_get_device_bad(cfg):
>      ksft_true(raised)
>  
>  
> +def dev_set_crypt_offset(cfg):
> +    """ Set and get the crypt-offset """
> +    _init_psp_dev(cfg)
> +
> +    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
> +    orig = dev['crypt-offset']
> +    cfg.pspnl.dev_set({"id": cfg.psp_dev_id,
> +                       "crypt-offset": 5})
> +    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
> +    ksft_eq(dev['crypt-offset'], 5)
> +    cfg.pspnl.dev_set({"id": cfg.psp_dev_id,
> +                       "crypt-offset": orig})
> +    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
> +    ksft_eq(dev['crypt-offset'], orig)
> +
> +
> +def dev_set_spi_threshold(cfg):
> +    """ Set and get the spi-threshold """
> +    _init_psp_dev(cfg)
> +
> +    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
> +    orig = dev['spi-threshold']
> +    cfg.pspnl.dev_set({"id": cfg.psp_dev_id,
> +                       "spi-threshold": 10})
> +    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
> +    ksft_eq(dev['spi-threshold'], 10)
> +    cfg.pspnl.dev_set({"id": cfg.psp_dev_id,
> +                       "spi-threshold": orig})
> +    dev = cfg.pspnl.dev_get({'id': cfg.psp_dev_id})
> +    ksft_eq(dev['spi-threshold'], orig)

These tests mainly verify that netlink works as intended. Not sure how
much value that brings.

Once crypt-offset requires bounds checking (say), such control ops
functional tests may become more valuable.

More interesting would be to see the effect on the datapath. E.g.,
a crypt-offset that actually leaves plaintext. Not sure how easy or
hard this is, so don't take this as a requirement. But maybe something
that achievable with PSP packetdrill (eventually)?

Re: [PATCH net-next 1/3] psp: add crypt-offset and spi-threshold get/set attributes

[Jakub Kicinski]

On Tue, 07 Apr 2026 17:37:41 -0400 Willem de Bruijn wrote:
> > +	if (info->attrs[PSP_A_DEV_CRYPT_OFFSET])
> > +		new_config.crypt_offset =
> > +			nla_get_u8(info->attrs[PSP_A_DEV_CRYPT_OFFSET]);  
> 
> PSP defines a 6-bit field in 4 octet units. Does this need bounds checking?

More fundamentally, were we to support this -- is it a device property
or an assoc property? 

Re: [PATCH net-next 0/3] psp: add crypt-offset and spi-threshold attributes

[Jakub Kicinski]

On Tue, 7 Apr 2026 21:09:38 +0530 Akhilesh Samineni wrote:
> > Please read this document:
> > https://www.kernel.org/doc/html/next/process/maintainer-netdev.html
> 
> Thank you for the link. I have reviewed the netdev process documentation.

It is one thing to make an unknowing mistake and another thing
to ignore someone asking you to read the documentation.
Please read the doc top to bottom and tell your entire team to read it.