Re: [PATCH v3 02/13] s390x/tcg: fix ignoring bit 63 when setting the storage key in SSKE

[Thomas Huth <thuth@redhat.com>]

On 03/09/2021 17.55, David Hildenbrand wrote:
> Right now we could set an 8-bit storage key via SSKE and retrieve it
> again via ISKE, which is against the architecture description:
> 
> SSKE:
> "
> The new seven-bit storage-key value, or selected bits
> thereof, is obtained from bit positions 56-62 of gen-
> eral register R 1 . The contents of bit positions 0-55
> and 63 of the register are ignored.
> "
> 
> ISKE:
> "
> The seven-bit storage key is inserted in bit positions
> 56-62 of general register R 1 , and bit 63 is set to zero.
> "
> 
> Let's properly ignore bit 63 to create the correct seven-bit storage key.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>   target/s390x/tcg/mem_helper.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/s390x/tcg/mem_helper.c b/target/s390x/tcg/mem_helper.c
> index e0befd0f03..3c0820dd74 100644
> --- a/target/s390x/tcg/mem_helper.c
> +++ b/target/s390x/tcg/mem_helper.c
> @@ -2210,7 +2210,7 @@ void HELPER(sske)(CPUS390XState *env, uint64_t r1, uint64_t r2)
>           skeyclass = S390_SKEYS_GET_CLASS(ss);
>       }
>   
> -    key = (uint8_t) r1;
> +    key = r1 & 0xfe;
>       skeyclass->set_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
>      /*
>       * As we can only flush by virtual address and not all the entries
> 

Reviewed-by: Thomas Huth <thuth@redhat.com>