Commit 447eb1d5 authored by Srish Srinivasan's avatar Srish Srinivasan Committed by Madhavan Srinivasan
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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: default avatarSrish Srinivasan <ssrish@linux.ibm.com>
Tested-by: default avatarNayna Jain <nayna@linux.ibm.com>
Reviewed-by: default avatarNayna Jain <nayna@linux.ibm.com>
Signed-off-by: default avatarMadhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260127145228.48320-4-ssrish@linux.ibm.com
parent 40850c90

Documentation/ABI/testing/sysfs-firmware-plpks

+8 −0
Original line number Diff line number Diff line
@@ -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

+3 −1
Original line number Diff line number Diff line
@@ -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

+3 −0
Original line number Diff line number Diff line
@@ -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

+2 −0
Original line number Diff line number Diff line
@@ -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

+20 −0
Original line number Diff line number Diff line
@@ -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.

 *