Re: [PATCH v8 07/11] scsi: ufs: Add inline encryption support to UFS

Eric Biggers
2020-03-15T18:38:59Z

On Thu, Mar 12, 2020 at 01:02:49AM -0700, Satya Tangirala wrote:
> Wire up ufshcd.c with the UFS Crypto API, the block layer inline
> encryption additions and the keyslot manager.
>
> Signed-off-by: Satya Tangirala <satyat@google.com>
> ---
> drivers/scsi/ufs/ufshcd-crypto.c | 27 +++++++++++++++
> drivers/scsi/ufs/ufshcd-crypto.h | 14 ++++++++
> drivers/scsi/ufs/ufshcd.c | 59 +++++++++++++++++++++++++++++---
> drivers/scsi/ufs/ufshcd.h | 8 +++++
> 4 files changed, 103 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd-crypto.c b/drivers/scsi/ufs/ufshcd-crypto.c
> index 8b6f7c83f77f..37254472326a 100644
> --- a/drivers/scsi/ufs/ufshcd-crypto.c
> +++ b/drivers/scsi/ufs/ufshcd-crypto.c
> @@ -368,3 +368,30 @@ void ufshcd_crypto_destroy_keyslot_manager(struct ufs_hba *hba)
> {
> blk_ksm_destroy(&hba->ksm);
> }
> +
> +int ufshcd_prepare_lrbp_crypto(struct ufs_hba *hba,
> + struct scsi_cmnd *cmd,
> + struct ufshcd_lrb *lrbp)
> +{
> + struct request *rq = cmd->request;
> + struct bio_crypt_ctx *bc = rq->crypt_ctx;
> + unsigned int slot_idx = blk_ksm_get_slot_idx(rq->crypt_keyslot);
> +
> + lrbp->crypto_enable = false;
> +
> + if (WARN_ON(!(hba->caps & UFSHCD_CAP_CRYPTO))) {
> + /*
> + * Upper layer asked us to do inline encryption
> + * but that isn't enabled, so we fail this request.
> + */
> + return -EINVAL;
> + }
> + if (!ufshcd_keyslot_valid(hba, slot_idx))
> + return -EINVAL;
> +
> + lrbp->crypto_enable = true;
> + lrbp->crypto_key_slot = slot_idx;
> + lrbp->data_unit_num = bc->bc_dun[0];
> +
> + return 0;
> +}
> diff --git a/drivers/scsi/ufs/ufshcd-crypto.h b/drivers/scsi/ufs/ufshcd-crypto.h
> index 8270c0c5081a..c76f93ede51c 100644
> --- a/drivers/scsi/ufs/ufshcd-crypto.h
> +++ b/drivers/scsi/ufs/ufshcd-crypto.h
> @@ -16,6 +16,15 @@ static inline bool ufshcd_hba_is_crypto_supported(struct ufs_hba *hba)
> return hba->crypto_capabilities.reg_val != 0;
> }
>
> +int ufshcd_prepare_lrbp_crypto(struct ufs_hba *hba,
> + struct scsi_cmnd *cmd,
> + struct ufshcd_lrb *lrbp);
> +
> +static inline bool ufshcd_lrbp_crypto_enabled(struct ufshcd_lrb *lrbp)
> +{
> + return lrbp->crypto_enable;
> +}
> +
> void ufshcd_crypto_enable(struct ufs_hba *hba);
>
> void ufshcd_crypto_disable(struct ufs_hba *hba);
> @@ -49,6 +58,11 @@ static inline void ufshcd_crypto_setup_rq_keyslot_manager(struct ufs_hba *hba,
> static inline void ufshcd_crypto_destroy_keyslot_manager(struct ufs_hba *hba)
> { }
>
> +static inline bool ufshcd_lrbp_crypto_enabled(struct ufshcd_lrb *lrbp)
> +{
> + return false;
> +}
> +
> #endif /* CONFIG_SCSI_UFS_CRYPTO */
>
> #endif /* _UFSHCD_CRYPTO_H */
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 825d9eb34f10..3a19966dbee9 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -47,6 +47,7 @@
> #include "unipro.h"
> #include "ufs-sysfs.h"
> #include "ufs_bsg.h"
> +#include "ufshcd-crypto.h"
>
> #define CREATE_TRACE_POINTS
> #include <trace/events/ufs.h>
> @@ -816,7 +817,14 @@ static void ufshcd_enable_run_stop_reg(struct ufs_hba *hba)
> */
> static inline void ufshcd_hba_start(struct ufs_hba *hba)
> {
> - ufshcd_writel(hba, CONTROLLER_ENABLE, REG_CONTROLLER_ENABLE);
> + u32 val = CONTROLLER_ENABLE;
> +
> + if (ufshcd_hba_is_crypto_supported(hba)) {
> + ufshcd_crypto_enable(hba);
> + val |= CRYPTO_GENERAL_ENABLE;
> + }
> +
> + ufshcd_writel(hba, val, REG_CONTROLLER_ENABLE);
> }
>
> /**
> @@ -2192,9 +2200,23 @@ static void ufshcd_prepare_req_desc_hdr(struct ufshcd_lrb *lrbp,
> dword_0 |= UTP_REQ_DESC_INT_CMD;
>
> /* Transfer request descriptor header fields */
> + if (ufshcd_lrbp_crypto_enabled(lrbp)) {
> +#ifdef CONFIG_SCSI_UFS_CRYPTO
> + dword_0 |= UTP_REQ_DESC_CRYPTO_ENABLE_CMD;
> + dword_0 |= lrbp->crypto_key_slot;
> + req_desc->header.dword_1 =
> + cpu_to_le32(lower_32_bits(lrbp->data_unit_num));
> + req_desc->header.dword_3 =
> + cpu_to_le32(upper_32_bits(lrbp->data_unit_num));
> +#endif /* CONFIG_SCSI_UFS_CRYPTO */
> + } else {
> + /* dword_1 and dword_3 are reserved, hence they are set to 0 */
> + req_desc->header.dword_1 = 0;
> + req_desc->header.dword_3 = 0;
> + }
> +
> req_desc->header.dword_0 = cpu_to_le32(dword_0);
> - /* dword_1 is reserved, hence it is set to 0 */
> - req_desc->header.dword_1 = 0;
> +
> /*
> * assigning invalid value for command status. Controller
> * updates OCS on command completion, with the command
> @@ -2202,8 +2224,6 @@ static void ufshcd_prepare_req_desc_hdr(struct ufshcd_lrb *lrbp,
> */
> req_desc->header.dword_2 =
> cpu_to_le32(OCS_INVALID_COMMAND_STATUS);
> - /* dword_3 is reserved, hence it is set to 0 */
> - req_desc->header.dword_3 = 0;
>
> req_desc->prd_table_length = 0;
> }
> @@ -2437,6 +2457,20 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
> lrbp->task_tag = tag;
> lrbp->lun = ufshcd_scsi_to_upiu_lun(cmd->device->lun);
> lrbp->intr_cmd = !ufshcd_is_intr_aggr_allowed(hba) ? true : false;
> +
> +#ifdef CONFIG_SCSI_UFS_CRYPTO
> + if (cmd->request->crypt_keyslot) {
> + err = ufshcd_prepare_lrbp_crypto(hba, cmd, lrbp);
> + if (err) {
> + lrbp->cmd = NULL;
> + ufshcd_release(hba);
> + goto out;
> + }
> + } else {
> + lrbp->crypto_enable = false;
> + }
> +#endif
> +
> lrbp->req_abort_skip = false;
>
> ufshcd_comp_scsi_upiu(hba, lrbp);
> @@ -2470,6 +2504,9 @@ static int ufshcd_compose_dev_cmd(struct ufs_hba *hba,
> lrbp->task_tag = tag;
> lrbp->lun = 0; /* device management cmd is not specific to any LUN */
> lrbp->intr_cmd = true; /* No interrupt aggregation */
> +#ifdef CONFIG_SCSI_UFS_CRYPTO
> + lrbp->crypto_enable = false; /* No crypto operations */
> +#endif
> hba->dev_cmd.type = cmd_type;
>
> return ufshcd_comp_devman_upiu(hba, lrbp);

This is all much more complicated than needed.

- We don't need the 'crypto_enable' field. Just make 'crypto_key_slot' an int
and use 'crypto_key_slot = -1' instead.

- ufshcd_lrbp_crypto_enabled() isn't needed since it's only used in one place
which uses an ifdef anyway. It can simply check crypto_key_slot >= 0.

- The checks in ufshcd_prepare_lrbp_crypto() are unneeded, as the block layer
already ensures that a valid keyslot is provided.

So for the per-command code, all we actually need is:

#ifdef CONFIG_SCSI_UFS_CRYPTO
static inline void ufshcd_prepare_lrbp_crypto(struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp)
{
struct request *rq = cmd->request;

if (rq->crypt_keyslot) {
lrbp->crypto_key_slot = blk_ksm_get_slot_idx(rq->crypt_keyslot);
lrbp->data_unit_num = rq->crypt_ctx->bc_dun[0];
} else {
lrbp->crypto_key_slot = -1;
}
}
...
#else
static inline void ufshcd_prepare_lrbp_crypto(struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp)
{
}
...
#endif

Then in ufshcd_queuecommand():

...

lrbp->intr_cmd = !ufshcd_is_intr_aggr_allowed(hba) ? true : false;
lrbp->req_abort_skip = false;

ufshcd_prepare_lrbp_crypto(cmd, lrbp);

ufshcd_comp_scsi_upiu(hba, lrbp);

...

Then in ufshcd_prepare_req_desc_hdr():

u32 dword_1 = 0;
u32 dword_3 = 0;

...

#ifdef CONFIG_SCSI_UFS_CRYPTO
if (lrbp->crypto_key_slot >= 0) {
dword_0 |= UTP_REQ_DESC_CRYPTO_ENABLE_CMD;
dword_0 |= lrbp->crypto_key_slot;
dword_1 = lower_32_bits(lrbp->data_unit_num);
dword_3 = upper_32_bits(lrbp->data_unit_num);
}
#endif

req_desc->header.dword_0 = cpu_to_le32(dword_0);
req_desc->header.dword_1 = cpu_to_le32(dword_1);
...
req_desc->header.dword_2 =
cpu_to_le32(OCS_INVALID_COMMAND_STATUS);
req_desc->header.dword_3 = cpu_to_le32(dword_3);