On 2025-04-22 at 0:24, Ashish Kalra wrote:
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-
> dev.c
> index b08db412f752..f4f8a8905115 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -232,6 +232,7 @@ static int sev_cmd_buffer_len(int cmd)
> case SEV_CMD_SNP_GUEST_REQUEST: return
> sizeof(struct sev_data_snp_guest_request);
> case SEV_CMD_SNP_CONFIG: return sizeof(struct
> sev_user_data_snp_config);
> case SEV_CMD_SNP_COMMIT: return sizeof(struct
> sev_data_snp_commit);
> + case SEV_CMD_SNP_FEATURE_INFO: return sizeof(struct
> snp_feature_info);
This function is supposed to return the size of the command buffer, so
for this command it should return sizeof(struct
sev_data_snp_feature_info).
> default: return 0;
> }
>
> @@ -1072,6 +1073,50 @@ static void snp_set_hsave_pa(void *arg)
> wrmsrq(MSR_VM_HSAVE_PA, 0);
> }
>
> +static void snp_get_platform_data(void)
> +{
> + struct sev_device *sev = psp_master->sev_data;
> + struct sev_data_snp_feature_info snp_feat_info;
> + struct snp_feature_info *feat_info;
> + struct sev_data_snp_addr buf;
> + int error = 0, rc;
> +
> + if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
> + return;
> +
> + /*
> + * The output buffer must be firmware page if SEV-SNP is
> + * initialized.
> + */
> + if (sev->snp_initialized)
> + return;
> +
> + buf.address = __psp_pa(&sev->snp_plat_status);
> + rc = __sev_do_cmd_locked(SEV_CMD_SNP_PLATFORM_STATUS, &buf,
> &error);
> +
> + /*
> + * Do feature discovery of the currently loaded firmware,
> + * and cache feature information from CPUID 0x8000_0024,
> + * sub-function 0.
> + */
> + if (!rc && sev->snp_plat_status.feature_info) {
> + /*
> + * Use dynamically allocated structure for the
> SNP_FEATURE_INFO
> + * command to handle any alignment and page boundary
> check
> + * requirements.
> + */
> + feat_info = kzalloc(sizeof(*feat_info), GFP_KERNEL);
The SEV firmware requires the supplied memory range to not cross a page
boundary, but kzalloc() does not guarantee that the allocated memory
fits this requirement. You need to allocate a larger chunk of memory (2
* sizeof(*feat_info) will be enough), and possibly set
feature_info_paddr to an offset from the start of the allocated memory.
