On Thu, 1 Dec 2022 09:46:41 +0100
Nico Boehr <nrb@xxxxxxxxxxxxx> wrote:
> Upcoming changes will change storage keys in a loop. To make sure each
> iteration of the loops sets different keys, add variants of the storage
> key library functions which allow to specify a seed.
>
> Signed-off-by: Nico Boehr <nrb@xxxxxxxxxxxxx>
I wonder if you can simply merge this patch with the previous one
> ---
> lib/s390x/skey.c | 12 +++++++-----
> lib/s390x/skey.h | 14 ++++++++++++--
> 2 files changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/lib/s390x/skey.c b/lib/s390x/skey.c
> index 100f0949a244..4ab0828ee98f 100644
> --- a/lib/s390x/skey.c
> +++ b/lib/s390x/skey.c
> @@ -14,10 +14,11 @@
> #include <skey.h>
>
> /*
> - * Set storage keys on pagebuf.
> + * Set storage keys on pagebuf with a seed for the storage keys.
> * pagebuf must point to page_count consecutive pages.
> + * Only the lower seven bits of the seed are considered.
> */
> -void skey_set_keys(uint8_t *pagebuf, unsigned long page_count)
> +void skey_set_keys_with_seed(uint8_t *pagebuf, unsigned long page_count, unsigned char seed)
> {
> unsigned char key_to_set;
> unsigned long i;
> @@ -30,7 +31,7 @@ void skey_set_keys(uint8_t *pagebuf, unsigned long page_count)
> * protection as well as reference and change indication for
> * some keys.
> */
> - key_to_set = i * 2;
> + key_to_set = (i ^ seed) * 2;
> set_storage_key(pagebuf + i * PAGE_SIZE, key_to_set, 1);
> }
> }
> @@ -38,13 +39,14 @@ void skey_set_keys(uint8_t *pagebuf, unsigned long page_count)
> /*
> * Verify storage keys on pagebuf.
> * Storage keys must have been set by skey_set_keys on pagebuf before.
> + * skey_set_keys must have been called with the same seed value.
> *
> * If storage keys match the expected result, will return a skey_verify_result
> * with verify_failed false. All other fields are then invalid.
> * If there is a mismatch, returned struct will have verify_failed true and will
> * be filled with the details on the first mismatch encountered.
> */
> -struct skey_verify_result skey_verify_keys(uint8_t *pagebuf, unsigned long page_count)
> +struct skey_verify_result skey_verify_keys_with_seed(uint8_t *pagebuf, unsigned long page_count, unsigned char seed)
> {
> union skey expected_key, actual_key;
> struct skey_verify_result result = {
> @@ -56,7 +58,7 @@ struct skey_verify_result skey_verify_keys(uint8_t *pagebuf, unsigned long page_
> for (i = 0; i < page_count; i++) {
> cur_page = pagebuf + i * PAGE_SIZE;
> actual_key.val = get_storage_key(cur_page);
> - expected_key.val = i * 2;
> + expected_key.val = (i ^ seed) * 2;
>
> /*
> * The PoP neither gives a guarantee that the reference bit is
> diff --git a/lib/s390x/skey.h b/lib/s390x/skey.h
> index a0f8caa1270b..bba1c131276d 100644
> --- a/lib/s390x/skey.h
> +++ b/lib/s390x/skey.h
> @@ -23,9 +23,19 @@ struct skey_verify_result {
> unsigned long page_mismatch_addr;
> };
>
> -void skey_set_keys(uint8_t *pagebuf, unsigned long page_count);
> +void skey_set_keys_with_seed(uint8_t *pagebuf, unsigned long page_count, unsigned char seed);
>
> -struct skey_verify_result skey_verify_keys(uint8_t *pagebuf, unsigned long page_count);
> +static inline void skey_set_keys(uint8_t *pagebuf, unsigned long page_count)
> +{
> + skey_set_keys_with_seed(pagebuf, page_count, 0);
> +}
> +
> +struct skey_verify_result skey_verify_keys_with_seed(uint8_t *pagebuf, unsigned long page_count, unsigned char seed);
> +
> +static inline struct skey_verify_result skey_verify_keys(uint8_t *pagebuf, unsigned long page_count)
> +{
> + return skey_verify_keys_with_seed(pagebuf, page_count, 0);
> +}
>
> void skey_report_verify(struct skey_verify_result * const result);
>
