--- name: "psp" section: "4" platform: "openbsd" package: "man" version: "8.0-current-20261101" release: "OpenBSD 8.0-current (2026-11-01)" platforms: ["openbsd"] url: "https://new.carta.tech/psp" --- # psp(4) AMD Platform Security Processor ## NAME **psp** – AMD Platform Security Processor ## SYNOPSIS **psp\* at ccp?** ## DESCRIPTION The **psp** driver provides an interface to the AMD Platform Security Processor. The interface can be accessed through the [ioctl(2)](/ioctl/2.md) interface exposed by */dev/psp*. [vmd(8)](/vmd/8.md) uses **psp** to configure and launch SEV-enabled guests. ## IOCTL INTERFACE The [ioctl(2)](/ioctl/2.md) command codes below are defined in ⟨dev/ic/pspvar.h⟩. - PSP\_IOC\_GET\_PSTATUS *struct psp\_platform\_status \*pspst* Collect the current status of the platform. ``` struct psp_platform_status { /* Output parameters from PSP_CMD_PLATFORMSTATUS */ uint8_t api_major; uint8_t api_minor; uint8_t state; uint8_t owner; uint32_t cfges_build; uint32_t guest_count; } __packed; ``` *api\_major* and *api\_minor* indicate the PSP firmware version. The current platform state is indicated by *state*. The following values are defined: - PSP\_PSTATE\_UNINIT The platform is uninitialized. - PSP\_PSTATE\_INIT The platform is initialized but not managing any guests. - PSP\_PSTATE\_WORKING The platform is initialized and currently managing guests. *owner* indicates whether the platform is self-owned or externally owned. Bit 0 of *cfgs\_build* indicates whether SEV-ES is configured on the platform or not. Bits 31:24 indicate the firmware build ID. *guest\_count* indicates the number of valid guests currently maintained by the firmware. - PSP\_IOC\_DF\_FLUSH This command flushes all write buffers of the CPU's data fabric. It must be invoked after deactivating one or more guests with PSP\_IOC\_DEACTIVATE. - PSP\_IOC\_DECOMMISSION *struct psp\_decommission \*pspdec* Deletes all guest context of the guest identified by *handle*. ``` struct psp_decommission { /* Input parameter for PSP_CMD_DECOMMISSION */ uint32_t handle; } __packed; ``` - PSP\_IOC\_GET\_GSTATUS Retrieves status information about an SEV-enabled guest identified by *handle*. ``` struct psp_guest_status { /* Input parameter for PSP_CMD_GUESTSTATUS */ uint32_t handle; /* Output parameters from PSP_CMD_GUESTSTATUS */ uint32_t policy; uint32_t asid; uint8_t state; } __packed; ``` *policy* indicates the policy used for this guest. *asid* indicates the guest's address space identifier (ASID). The state of the guest is indicated by *state*. The following values are defined: - PSP\_GSTATE\_UNINIT The guest is uninitialized. - PSP\_GSTATE\_LUPDATE The guest is currently being launched and plaintext data is imported. - PSP\_GSTATE\_LSECRET The guest is currently being launched and ciphertext data is imported. - PSP\_GSTATE\_RUNNING The guest is fully launched. - PSP\_GSTATE\_SUPDATE The guest is migrated to another machine. - PSP\_GSTATE\_RUPDATE The guest is migrated from another machine. - PSP\_GSTATE\_SENT Thee guest has bin migrated to another machine. - PSP\_IOC\_LAUNCH\_START This command encrypts a guest's memory. ``` struct psp_launch_start { /* Input/Output parameter for PSP_CMD_LAUNCH_START */ uint32_t handle; /* Input parameters for PSP_CMD_LAUNCH_START */ uint32_t policy; /* The following input parameters are not used yet */ uint64_t dh_cert_paddr; uint32_t dh_cert_len; uint32_t reserved; uint64_t session_paddr; uint32_t session_len; } __packed; ``` If *handle* is zero, a new key is created. A unique handle is assigned to the guest and returned in *handle*. *policy* specifies the policy used for that guest. *dh\_cert\_paddr*, *dh\_cert* *len*, *session\_paddr* and *session\_len* are currently not used. - PSP\_IOC\_LAUNCH\_UPDATE\_DATA This command encrypts data of the guest identified by *handle*. ``` struct psp_launch_update_data { /* Input parameters for PSP_CMD_LAUNCH_UPDATE_DATA */ uint32_t handle; uint32_t reserved; uint64_t paddr; uint32_t length; } __packed; ``` *paddr* and *length* specify the address and length of the data to be encrypted. Both values must be a multiple of 16 bytes. - PSP\_IOC\_LAUNCH\_MEASURE This commands generates a measurement of the guest's memory. The guest is identified by *handle*. ``` struct psp_measure { /* Output buffer for PSP_CMD_LAUNCH_MEASURE */ uint8_t measure[32]; uint8_t measure_nonce[16]; } __packed; struct psp_launch_measure { /* Input parameters for PSP_CMD_LAUNCH_MEASURE */ uint32_t handle; uint32_t reserved; uint64_t measure_paddr; /* Input/output parameter for PSP_CMD_LAUNCH_MEASURE */ uint32_t measure_len; uint32_t padding; /* Output buffer from PSP_CMD_LAUNCH_MEASURE */ struct psp_measure psp_measure; /* 64bit aligned */ #define measure psp_measure.measure #define measure_nonce psp_measure.measure_nonce } __packed; ``` *measure\_paddr* is currently not used and *measure\_len* must always be sizeof(struct psp\_measure). *psp\_measure* contains the buffers *measure* and *measure\_nonce*. These contain the measurement and nonce generated by the PSP. - PSP\_IOC\_LAUNCH\_FINISH This command finalizes the launch of the guest identified by *handle*. ``` struct psp_launch_finish { /* Input parameter for PSP_CMD_LAUNCH_FINISH */ uint32_t handle; } __packed; ``` - PSP\_IOC\_ATTESTATION This command generates an attestation report signed by the PSP with a platform specific key. ``` struct psp_report { /* Output buffer for PSP_CMD_ATTESTATION */ uint8_t report_nonce[16]; uint8_t report_launch_digest[32]; uint32_t report_policy; uint32_t report_sig_usage; uint32_t report_sig_algo; uint32_t reserved2; uint8_t report_sig1[144]; } __packed; struct psp_attestation { /* Input parameters for PSP_CMD_ATTESTATION */ uint32_t handle; uint32_t reserved; uint64_t attest_paddr; uint8_t attest_nonce[16]; /* Input/output parameter from PSP_CMD_ATTESTATION */ uint32_t attest_len; uint32_t padding; /* Output parameter from PSP_CMD_ATTESTATION */ struct psp_report psp_report; /* 64bit aligned */ #define report_nonce psp_report.report_nonce #define report_launch_digest psp_report.report_launch_digest #define report_policy psp_report.report_policy #define report_sig_usage psp_report.report_sig_usage; #define report_report_sig_alg psp_report.report_sig_algo; #define report_report_sig1 psp_report.report_sig1; } __packed; ``` *handle* identifies the guest. *attest\_paddr* is currently not used. *attest\_nonce* is the nonce returned by a previous PSP\_IOC\_LAUNCH\_MEASURE command. *attest\_len* must always be sizeof(struct psp\_report). The attestation report is returned in *psp\_report*. The format of the report is defined by struct psp\_report. - PSP\_IOC\_ACTIVATE This commands associates the context of the guest identified by *handle* with the address space identifier provided in *asid*. ``` struct psp_activate { /* Input parameters for PSP_CMD_ACTIVATE */ uint32_t handle; uint32_t asid; } __packed; ``` - PSP\_IOC\_DEACTIVATE This command dissociates the context of the guest identified by *handle* from its current the address space identifier. ``` struct psp_deactivate { /* Input parameter for PSP_CMD_DEACTIVATE */ uint32_t handle; } __packed; ``` - PSP\_IOC\_SNP\_GET\_PSTATUS This command returns the state of a SEV-SNP enabled platform. ``` struct psp_snp_platform_status { uint8_t api_major; uint8_t api_minor; uint8_t state; uint8_t is_rmp_init; uint32_t build; uint32_t features; uint32_t guest_count; uint64_t current_tcb; uint64_t reported_tcb; } __packed; ``` - PSP\_IOC\_GUEST\_SHUTDOWN This command shuts down a guest identified by *handle*. ``` struct psp_guest_shutdown { /* Input parameter for PSP_CMD_GUEST_SHUTDOWN */ uint32_t handle; } __packed; ``` The command combines PSP\_IOC\_DEACTIVATE and PSP\_IOC\_DECOMMISSION in a single [ioctl(2)](/ioctl/2.md) call. ## FILES - */dev/psp* ## SEE ALSO [ioctl(2)](/ioctl/2.md), [ccp(4)](/ccp/4.md), [vmd(8)](/vmd/8.md) *Secure Encrypted Virtualization API*, Publication #55766. *SEV Secure Nested Paging Firmware ABI Specification*, Publication #56860. ## HISTORY The **psp** device driver first appeared in OpenBSD 7.6. ## AUTHORS The **psp** driver was written by Hans-Joerg Hoexer ⟨*hshoexer@genua.de*⟩.