Re: [Qemu-devel] [PATCH 2/6] target/arm: Fix SVE system register access checks

[Philippe Mathieu-Daudé]

On 06/28/2018 09:15 PM, Richard Henderson wrote:
> Leave ARM_CP_SVE, removing ARM_CP_FPU; the sve_access_check
> produced by the flag already includes fp_access_check.  If
> we also check ARM_CP_FPU the double fp_access_check asserts.

Maybe we can surround this assert() with #ifdef DEBUG_DISAS...

> Reported-by: Laurent Desnogues <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  target/arm/helper.c        | 8 ++++----
>  target/arm/translate-a64.c | 5 ++---
>  2 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index b19c7ace78..a855da045b 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -4393,7 +4393,7 @@ static void zcr_write(CPUARMState *env, const 
> ARMCPRegInfo *ri,
>  static const ARMCPRegInfo zcr_el1_reginfo = {
>      .name = "ZCR_EL1", .state = ARM_CP_STATE_AA64,
>      .opc0 = 3, .opc1 = 0, .crn = 1, .crm = 2, .opc2 = 0,
> -    .access = PL1_RW, .type = ARM_CP_SVE | ARM_CP_FPU,
> +    .access = PL1_RW, .type = ARM_CP_SVE,
>      .fieldoffset = offsetof(CPUARMState, vfp.zcr_el[1]),
>      .writefn = zcr_write, .raw_writefn = raw_write
>  };
> @@ -4401,7 +4401,7 @@ static const ARMCPRegInfo zcr_el1_reginfo = {
>  static const ARMCPRegInfo zcr_el2_reginfo = {
>      .name = "ZCR_EL2", .state = ARM_CP_STATE_AA64,
>      .opc0 = 3, .opc1 = 4, .crn = 1, .crm = 2, .opc2 = 0,
> -    .access = PL2_RW, .type = ARM_CP_SVE | ARM_CP_FPU,
> +    .access = PL2_RW, .type = ARM_CP_SVE,
>      .fieldoffset = offsetof(CPUARMState, vfp.zcr_el[2]),
>      .writefn = zcr_write, .raw_writefn = raw_write
>  };
> @@ -4409,14 +4409,14 @@ static const ARMCPRegInfo zcr_el2_reginfo = {
>  static const ARMCPRegInfo zcr_no_el2_reginfo = {
>      .name = "ZCR_EL2", .state = ARM_CP_STATE_AA64,
>      .opc0 = 3, .opc1 = 4, .crn = 1, .crm = 2, .opc2 = 0,
> -    .access = PL2_RW, .type = ARM_CP_SVE | ARM_CP_FPU,
> +    .access = PL2_RW, .type = ARM_CP_SVE,
>      .readfn = arm_cp_read_zero, .writefn = arm_cp_write_ignore
>  };
>  
>  static const ARMCPRegInfo zcr_el3_reginfo = {
>      .name = "ZCR_EL3", .state = ARM_CP_STATE_AA64,
>      .opc0 = 3, .opc1 = 6, .crn = 1, .crm = 2, .opc2 = 0,
> -    .access = PL3_RW, .type = ARM_CP_SVE | ARM_CP_FPU,
> +    .access = PL3_RW, .type = ARM_CP_SVE,
>      .fieldoffset = offsetof(CPUARMState, vfp.zcr_el[3]),
>      .writefn = zcr_write, .raw_writefn = raw_write
>  };
> diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
> index f986340832..45a6c2a3aa 100644
> --- a/target/arm/translate-a64.c
> +++ b/target/arm/translate-a64.c
> @@ -1633,11 +1633,10 @@ static void handle_sys(DisasContext *s, uint32_t 
> insn, bool isread,
>      default:
>          break;
>      }
> -    if ((ri->type & ARM_CP_SVE) && !sve_access_check(s)) {
> -        return;
> -    }
>      if ((ri->type & ARM_CP_FPU) && !fp_access_check(s)) {
>          return;
> +    } else if ((ri->type & ARM_CP_SVE) && !sve_access_check(s)) {
> +        return;
>      }
>  
>      if ((tb_cflags(s->base.tb) & CF_USE_ICOUNT) && (ri->type & ARM_CP_IO)) {
>