Re: [Qemu-devel] [PATCH 1/2] target-ppc: fix vcipher, vcipherlast, vncipherlast and vpermxor

[Thomas Huth <thuth@redhat.com>]

On 13/09/15 23:03, Aurelien Jarno wrote:
> For vector instructions, the helpers get pointers to the vector register
> in arguments. Some operands might point to the same register, including
> the operand holding the result.
> 
> When emulating instructions which access the vector elements in a
> non-linear way, we need to store the result in an temporary variable.
> 
> This fixes openssl when emulating a POWER8 CPU.
> 
> Cc: Tom Musta <tommusta@gmail.com>
> Cc: Alexander Graf <agraf@suse.de>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
> ---
>  target-ppc/int_helper.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/target-ppc/int_helper.c b/target-ppc/int_helper.c
> index 0a55d5e..b122868 100644
> --- a/target-ppc/int_helper.c
> +++ b/target-ppc/int_helper.c
> @@ -2327,24 +2327,28 @@ void helper_vsbox(ppc_avr_t *r, ppc_avr_t *a)
>  
>  void helper_vcipher(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
>  {
> +    ppc_avr_t result;
>      int i;
>  
>      VECTOR_FOR_INORDER_I(i, u32) {
> -        r->AVRW(i) = b->AVRW(i) ^
> +        result.AVRW(i) = b->AVRW(i) ^
>              (AES_Te0[a->AVRB(AES_shifts[4*i + 0])] ^
>               AES_Te1[a->AVRB(AES_shifts[4*i + 1])] ^
>               AES_Te2[a->AVRB(AES_shifts[4*i + 2])] ^
>               AES_Te3[a->AVRB(AES_shifts[4*i + 3])]);
>      }
> +    *r = result;
>  }
>  
>  void helper_vcipherlast(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
>  {
> +    ppc_avr_t result;
>      int i;
>  
>      VECTOR_FOR_INORDER_I(i, u8) {
> -        r->AVRB(i) = b->AVRB(i) ^ (AES_sbox[a->AVRB(AES_shifts[i])]);
> +        result.AVRB(i) = b->AVRB(i) ^ (AES_sbox[a->AVRB(AES_shifts[i])]);
>      }
> +    *r = result;
>  }
>  
>  void helper_vncipher(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
> @@ -2369,11 +2373,13 @@ void helper_vncipher(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
>  
>  void helper_vncipherlast(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
>  {
> +    ppc_avr_t result;
>      int i;
>  
>      VECTOR_FOR_INORDER_I(i, u8) {
> -        r->AVRB(i) = b->AVRB(i) ^ (AES_isbox[a->AVRB(AES_ishifts[i])]);
> +        result.AVRB(i) = b->AVRB(i) ^ (AES_isbox[a->AVRB(AES_ishifts[i])]);
>      }
> +    *r = result;
>  }
>  
>  #define ROTRu32(v, n) (((v) >> (n)) | ((v) << (32-n)))
> @@ -2460,16 +2466,19 @@ void helper_vshasigmad(ppc_avr_t *r,  ppc_avr_t *a, uint32_t st_six)
>  
>  void helper_vpermxor(ppc_avr_t *r,  ppc_avr_t *a, ppc_avr_t *b, ppc_avr_t *c)
>  {
> +    ppc_avr_t result;
>      int i;
> +
>      VECTOR_FOR_INORDER_I(i, u8) {
>          int indexA = c->u8[i] >> 4;
>          int indexB = c->u8[i] & 0xF;
>  #if defined(HOST_WORDS_BIGENDIAN)
> -        r->u8[i] = a->u8[indexA] ^ b->u8[indexB];
> +        result.u8[i] = a->u8[indexA] ^ b->u8[indexB];
>  #else
> -        r->u8[i] = a->u8[15-indexA] ^ b->u8[15-indexB];
> +        result.u8[i] = a->u8[15-indexA] ^ b->u8[15-indexB];
>  #endif
>      }
> +    *r = result;
>  }
>  
>  #undef VECTOR_FOR_INORDER_I
> 

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