diff options
| -rw-r--r-- | arch/x86/coco/sev/core.c | 58 | ||||
| -rw-r--r-- | arch/x86/include/asm/sev.h | 7 |
2 files changed, 65 insertions, 0 deletions
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c index b0c1a7a57497..ecd09dad87f2 100644 --- a/arch/x86/coco/sev/core.c +++ b/arch/x86/coco/sev/core.c @@ -2625,6 +2625,64 @@ e_restore_irq: return ret; } +/** + * snp_svsm_vtpm_probe() - Probe if SVSM provides a vTPM device + * + * Check that there is SVSM and that it supports at least TPM_SEND_COMMAND + * which is the only request used so far. + * + * Return: true if the platform provides a vTPM SVSM device, false otherwise. + */ +static bool snp_svsm_vtpm_probe(void) +{ + struct svsm_call call = {}; + + /* The vTPM device is available only if a SVSM is present */ + if (!snp_vmpl) + return false; + + call.caa = svsm_get_caa(); + call.rax = SVSM_VTPM_CALL(SVSM_VTPM_QUERY); + + if (svsm_perform_call_protocol(&call)) + return false; + + /* Check platform commands contains TPM_SEND_COMMAND - platform command 8 */ + return call.rcx_out & BIT_ULL(8); +} + +/** + * snp_svsm_vtpm_send_command() - Execute a vTPM operation on SVSM + * @buffer: A buffer used to both send the command and receive the response. + * + * Execute a SVSM_VTPM_CMD call as defined by + * "Secure VM Service Module for SEV-SNP Guests" Publication # 58019 Revision: 1.00 + * + * All command request/response buffers have a common structure as specified by + * the following table: + * Byte Size In/Out Description + * Offset (Bytes) + * 0x000 4 In Platform command + * Out Platform command response size + * + * Each command can build upon this common request/response structure to create + * a structure specific to the command. See include/linux/tpm_svsm.h for more + * details. + * + * Return: 0 on success, -errno on failure + */ +int snp_svsm_vtpm_send_command(u8 *buffer) +{ + struct svsm_call call = {}; + + call.caa = svsm_get_caa(); + call.rax = SVSM_VTPM_CALL(SVSM_VTPM_CMD); + call.rcx = __pa(buffer); + + return svsm_perform_call_protocol(&call); +} +EXPORT_SYMBOL_GPL(snp_svsm_vtpm_send_command); + static struct platform_device sev_guest_device = { .name = "sev-guest", .id = -1, diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index ba7999f66abe..d9ba035d8609 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -384,6 +384,10 @@ struct svsm_call { #define SVSM_ATTEST_SERVICES 0 #define SVSM_ATTEST_SINGLE_SERVICE 1 +#define SVSM_VTPM_CALL(x) ((2ULL << 32) | (x)) +#define SVSM_VTPM_QUERY 0 +#define SVSM_VTPM_CMD 1 + #ifdef CONFIG_AMD_MEM_ENCRYPT extern u8 snp_vmpl; @@ -481,6 +485,8 @@ void snp_msg_free(struct snp_msg_desc *mdesc); int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req, struct snp_guest_request_ioctl *rio); +int snp_svsm_vtpm_send_command(u8 *buffer); + void __init snp_secure_tsc_prepare(void); void __init snp_secure_tsc_init(void); @@ -524,6 +530,7 @@ static inline struct snp_msg_desc *snp_msg_alloc(void) { return NULL; } static inline void snp_msg_free(struct snp_msg_desc *mdesc) { } static inline int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req, struct snp_guest_request_ioctl *rio) { return -ENODEV; } +static inline int snp_svsm_vtpm_send_command(u8 *buffer) { return -ENODEV; } static inline void __init snp_secure_tsc_prepare(void) { } static inline void __init snp_secure_tsc_init(void) { } |