On 7/1/25 15:15, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@xxxxxxx>
>
> Ciphertext hiding needs to be enabled on SNP_INIT_EX.
How about:
In order for ciphertext hiding to be enabled, it must be specified on
the SNP_INIT_EX command as part of SNP initialization.
>
> Enhance sev_platform_init_args by adding a new argument that enables the
> KVM module to specify whether the Ciphertext Hiding feature should be
> activated during SNP initialization. Additionally, this argument will
> allow for the definition of the maximum ASID that can be used for an
> SEV-SNP guest when Ciphertext Hiding is enabled.
Modify the sev_platform_init_args structure used as input to
sev_platform_init(), to add a field that, when non-zero, indicates
ciphertext hiding should be enabled and indicates the maximum ASID that
can be used for an SEV-SNP guest.
I think that reads a bit cleaner and clearer.
>
> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
> ---
> drivers/crypto/ccp/sev-dev.c | 12 +++++++++---
> include/linux/psp-sev.h | 10 ++++++++--
> 2 files changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index 3f2bbba93617..c883ccf8c3ff 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -1186,7 +1186,7 @@ static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
> return 0;
> }
>
> -static int __sev_snp_init_locked(int *error)
> +static int __sev_snp_init_locked(int *error, unsigned int max_snp_asid)
> {
> struct psp_device *psp = psp_master;
> struct sev_data_snp_init_ex data;
> @@ -1247,6 +1247,12 @@ static int __sev_snp_init_locked(int *error)
> }
>
> memset(&data, 0, sizeof(data));
> +
> + if (max_snp_asid) {
> + data.ciphertext_hiding_en = 1;
> + data.max_snp_asid = max_snp_asid;
> + }
> +
> data.init_rmp = 1;
> data.list_paddr_en = 1;
> data.list_paddr = __psp_pa(snp_range_list);
> @@ -1433,7 +1439,7 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
> if (sev->sev_plat_status.state == SEV_STATE_INIT)
> return 0;
>
> - rc = __sev_snp_init_locked(&args->error);
> + rc = __sev_snp_init_locked(&args->error, args->max_snp_asid);
> if (rc && rc != -ENODEV)
> return rc;
>
> @@ -1516,7 +1522,7 @@ static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_req
> {
> int error, rc;
>
> - rc = __sev_snp_init_locked(&error);
> + rc = __sev_snp_init_locked(&error, 0);
> if (rc) {
> argp->error = SEV_RET_INVALID_PLATFORM_STATE;
> return rc;
> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> index ca19fddfcd4d..b6eda9c560ee 100644
> --- a/include/linux/psp-sev.h
> +++ b/include/linux/psp-sev.h
> @@ -748,10 +748,13 @@ struct sev_data_snp_guest_request {
> struct sev_data_snp_init_ex {
> u32 init_rmp:1;
> u32 list_paddr_en:1;
> - u32 rsvd:30;
> + u32 rapl_dis:1;
> + u32 ciphertext_hiding_en:1;
> + u32 rsvd:28;
> u32 rsvd1;
> u64 list_paddr;
> - u8 rsvd2[48];
> + u16 max_snp_asid;
> + u8 rsvd2[46];
> } __packed;
>
> /**
> @@ -800,10 +803,13 @@ struct sev_data_snp_shutdown_ex {
> * @probe: True if this is being called as part of CCP module probe, which
> * will defer SEV_INIT/SEV_INIT_EX firmware initialization until needed
> * unless psp_init_on_probe module param is set
> + * @max_snp_asid: maximum ASID usable for SEV-SNP guest if
> + * CipherTextHiding feature is to be enabled
when non-zero, enable ciphertext hiding and specify the maximum ASID
that can be used for an SEV-SNP guest.
Thanks,
Tom
> */
> struct sev_platform_init_args {
> int error;
> bool probe;
> + unsigned int max_snp_asid;
> };
>
> /**
