From: Brijesh Singh <brijesh.singh@xxxxxxx> Version 2 of the GHCB specification defines VMGEXIT that is used to get the extended attestation report. The extended attestation report includes the certificate blobs provided through the SNP_SET_EXT_CONFIG. The snp_guest_ext_guest_request() will be used by the hypervisor to get the extended attestation report. See the GHCB specification for more details. Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx> Signed-off-by: Michael Roth <michael.roth@xxxxxxx> --- drivers/crypto/ccp/sev-dev.c | 47 ++++++++++++++++++++++++++++++++++++ include/linux/psp-sev.h | 33 +++++++++++++++++++++++++ 2 files changed, 80 insertions(+) diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index b56b00ca2cd4..e65563bc8298 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -2017,6 +2017,53 @@ int sev_guest_df_flush(int *error) } EXPORT_SYMBOL_GPL(sev_guest_df_flush); +int snp_guest_ext_guest_request(struct sev_data_snp_guest_request *data, + unsigned long vaddr, unsigned long *npages, unsigned long *fw_err) +{ + unsigned long expected_npages; + struct sev_device *sev; + int rc; + + if (!psp_master || !psp_master->sev_data) + return -ENODEV; + + sev = psp_master->sev_data; + + if (!sev->snp_initialized) + return -EINVAL; + + mutex_lock(&sev->snp_certs_lock); + /* + * Check if there is enough space to copy the certificate chain. Otherwise + * return ERROR code defined in the GHCB specification. + */ + expected_npages = sev->snp_certs_len >> PAGE_SHIFT; + if (*npages < expected_npages) { + *npages = expected_npages; + *fw_err = SNP_GUEST_REQ_INVALID_LEN; + mutex_unlock(&sev->snp_certs_lock); + return -EINVAL; + } + + rc = sev_do_cmd(SEV_CMD_SNP_GUEST_REQUEST, data, (int *)fw_err); + if (rc) { + mutex_unlock(&sev->snp_certs_lock); + return rc; + } + + /* Copy the certificate blob */ + if (sev->snp_certs_data) { + *npages = expected_npages; + memcpy((void *)vaddr, sev->snp_certs_data, *npages << PAGE_SHIFT); + } else { + *npages = 0; + } + + mutex_unlock(&sev->snp_certs_lock); + return rc; +} +EXPORT_SYMBOL_GPL(snp_guest_ext_guest_request); + static void sev_exit(struct kref *ref) { misc_deregister(&misc_dev->misc); diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h index d19744807471..81bafc049eca 100644 --- a/include/linux/psp-sev.h +++ b/include/linux/psp-sev.h @@ -931,6 +931,32 @@ void snp_free_firmware_page(void *addr); */ void snp_mark_pages_offline(unsigned long pfn, unsigned int npages); +/** + * snp_guest_ext_guest_request - perform the SNP extended guest request command + * defined in the GHCB specification. + * + * @data: the input guest request structure + * @vaddr: address where the certificate blob need to be copied. + * @npages: number of pages for the certificate blob. + * If the specified page count is less than the certificate blob size, then the + * required page count is returned with error code defined in the GHCB spec. + * If the specified page count is more than the certificate blob size, then + * page count is updated to reflect the amount of valid data copied in the + * vaddr. + * + * @sev_ret: sev command return code + * + * Returns: + * 0 if the sev successfully processed the command + * -%ENODEV if the sev device is not available + * -%ENOTSUPP if the sev does not support SEV + * -%ETIMEDOUT if the sev command timed out + * -%EIO if the sev returned a non-zero return code + */ +int snp_guest_ext_guest_request(struct sev_data_snp_guest_request *data, + unsigned long vaddr, unsigned long *npages, + unsigned long *error); + #else /* !CONFIG_CRYPTO_DEV_SP_PSP */ static inline int @@ -968,6 +994,13 @@ static inline void *snp_alloc_firmware_page(gfp_t mask) static inline void snp_free_firmware_page(void *addr) { } +static inline int snp_guest_ext_guest_request(struct sev_data_snp_guest_request *data, + unsigned long vaddr, unsigned long *n, + unsigned long *error) +{ + return -ENODEV; +} + #endif /* CONFIG_CRYPTO_DEV_SP_PSP */ #endif /* __PSP_SEV_H__ */ -- 2.25.1