pseries/plpks: expose PowerVM wrapping features via the sysfs

Starting with Power11, PowerVM supports a new feature called "Key Wrapping"
that protects user secrets by wrapping them using a hypervisor generated
wrapping key. The status of this feature can be read by the
H_PKS_GET_CONFIG HCALL.

Expose the Power LPAR Platform KeyStore (PLPKS) wrapping features config
via the sysfs file /sys/firmware/plpks/config/wrapping_features.

Signed-off-by: Srish Srinivasan <ssrish@linux.ibm.com>
Tested-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260127145228.48320-4-ssrish@linux.ibm.com

Author: ssrish17

Documentation/ABI/testing/sysfs-firmware-plpks

@@ -48,3 +48,11 @@ Description:	Bitmask of flags indicating which algorithms the hypervisor
 		supports for signed update of objects, represented as a 16 byte
 		hexadecimal ASCII string. Consult the hypervisor documentation
 		for what these flags mean.
+
+What:		/sys/firmware/plpks/config/wrapping_features
+Date:		November 2025
+Contact:	Srish Srinivasan <ssrish@linux.ibm.com>
+Description:	Bitmask of the wrapping features indicating the wrapping
+		algorithms that are supported for the H_PKS_WRAP_OBJECT requests
+		, represented as a 8 byte hexadecimal ASCII string. Consult the
+		hypervisor documentation for what these flags mean.

arch/powerpc/include/asm/hvcall.h

@@ -360,7 +360,9 @@
 #define H_GUEST_RUN_VCPU	0x480
 #define H_GUEST_COPY_MEMORY	0x484
 #define H_GUEST_DELETE		0x488
-#define MAX_HCALL_OPCODE	H_GUEST_DELETE
+#define H_PKS_WRAP_OBJECT	0x490
+#define H_PKS_UNWRAP_OBJECT	0x494
+#define MAX_HCALL_OPCODE	H_PKS_UNWRAP_OBJECT
 
 /* Scope args for H_SCM_UNBIND_ALL */
 #define H_UNBIND_SCOPE_ALL (0x1)

arch/powerpc/include/asm/plpks.h

@@ -23,6 +23,7 @@
 #define PLPKS_IMMUTABLE		PPC_BIT32(5) // Once written, object cannot be removed
 #define PLPKS_TRANSIENT		PPC_BIT32(6) // Object does not persist through reboot
 #define PLPKS_SIGNEDUPDATE	PPC_BIT32(7) // Object can only be modified by signed updates
+#define PLPKS_WRAPPINGKEY	PPC_BIT32(8) // Object contains a wrapping key
 #define PLPKS_HVPROVISIONED	PPC_BIT32(28) // Hypervisor has provisioned this object
 
 // Signature algorithm flags from signed_update_algorithms
@@ -103,6 +104,8 @@ u32 plpks_get_maxlargeobjectsize(void);
 
 u64 plpks_get_signedupdatealgorithms(void);
 
+u64 plpks_get_wrappingfeatures(void);
+
 u16 plpks_get_passwordlen(void);
 
 void plpks_early_init_devtree(void);

arch/powerpc/platforms/pseries/plpks-sysfs.c

@@ -30,6 +30,7 @@ PLPKS_CONFIG_ATTR(used_space, "%u\n", plpks_get_usedspace);
 PLPKS_CONFIG_ATTR(supported_policies, "%08x\n", plpks_get_supportedpolicies);
 PLPKS_CONFIG_ATTR(signed_update_algorithms, "%016llx\n",
 		  plpks_get_signedupdatealgorithms);
+PLPKS_CONFIG_ATTR(wrapping_features, "%016llx\n", plpks_get_wrappingfeatures);
 
 static const struct attribute *config_attrs[] = {
 	&attr_version.attr,
@@ -38,6 +39,7 @@ static const struct attribute *config_attrs[] = {
 	&attr_used_space.attr,
 	&attr_supported_policies.attr,
 	&attr_signed_update_algorithms.attr,
+	&attr_wrapping_features.attr,
 	NULL,
 };
 

arch/powerpc/platforms/pseries/plpks.c

@@ -38,6 +38,7 @@ static u32 usedspace;
 static u32 supportedpolicies;
 static u32 maxlargeobjectsize;
 static u64 signedupdatealgorithms;
+static u64 wrappingfeatures;
 
 struct plpks_auth {
 	u8 version;
@@ -248,6 +249,7 @@ static int _plpks_get_config(void)
 		__be32 supportedpolicies;
 		__be32 maxlargeobjectsize;
 		__be64 signedupdatealgorithms;
+		__be64 wrappingfeatures;
 		u8 rsvd1[476];
 	} __packed * config;
 	size_t size;
@@ -280,6 +282,7 @@ static int _plpks_get_config(void)
 	supportedpolicies = be32_to_cpu(config->supportedpolicies);
 	maxlargeobjectsize = be32_to_cpu(config->maxlargeobjectsize);
 	signedupdatealgorithms = be64_to_cpu(config->signedupdatealgorithms);
+	wrappingfeatures = be64_to_cpu(config->wrappingfeatures);
 
 	// Validate that the numbers we get back match the requirements of the spec
 	if (maxpwsize < 32) {
@@ -472,6 +475,23 @@ u64 plpks_get_signedupdatealgorithms(void)
 	return signedupdatealgorithms;
 }
 
+/**
+ * plpks_get_wrappingfeatures() - Returns a bitmask of the wrapping features
+ * supported by the hypervisor.
+ *
+ * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
+ * reads a bitmask of the wrapping features supported by the hypervisor into the
+ * file local static wrappingfeatures variable. This is valid only when the
+ * PLPKS config structure version >= 3.
+ *
+ * Return:
+ *	bitmask of the wrapping features supported by the hypervisor
+ */
+u64 plpks_get_wrappingfeatures(void)
+{
+	return wrappingfeatures;
+}
+
 /**
  * plpks_get_passwordlen() - Get the length of the PLPKS password in bytes.
  *