Re: [Qemu-devel] [PATCH v3 01/31] target/arm: Add state for the ARMv8.3-PAuth extension

[Peter Maydell]

On Tue, 8 Jan 2019 at 22:31, Richard Henderson
<address@hidden> wrote:
>
> Add storage space for the 5 encryption keys.
>
> Reviewed-by: Peter Maydell <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
> ----
> v2: Remove pointless double migration.
>     Use a struct to make it clear which half is which.
> ---
>  target/arm/cpu.h | 30 +++++++++++++++++++++++++++++-
>  1 file changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/target/arm/cpu.h b/target/arm/cpu.h
> index 6f606eb97b..8b891bbc30 100644
> --- a/target/arm/cpu.h
> +++ b/target/arm/cpu.h
> @@ -201,11 +201,16 @@ typedef struct ARMVectorReg {
>      uint64_t d[2 * ARM_MAX_VQ] QEMU_ALIGNED(16);
>  } ARMVectorReg;
>
> -/* In AArch32 mode, predicate registers do not exist at all.  */
>  #ifdef TARGET_AARCH64
> +/* In AArch32 mode, predicate registers do not exist at all.  */
>  typedef struct ARMPredicateReg {
>      uint64_t p[2 * ARM_MAX_VQ / 8] QEMU_ALIGNED(16);
>  } ARMPredicateReg;
> +
> +/* In AArch32 mode, PAC keys do not exist at all.  */
> +typedef struct ARMPACKey {
> +    uint64_t lo, hi;
> +} ARMPACKey;
>  #endif
>
>
> @@ -605,6 +610,14 @@ typedef struct CPUARMState {
>          uint32_t cregs[16];
>      } iwmmxt;
>
> +#ifdef TARGET_AARCH64
> +    ARMPACKey apia_key;
> +    ARMPACKey apib_key;
> +    ARMPACKey apda_key;
> +    ARMPACKey apdb_key;
> +    ARMPACKey apga_key;
> +#endif
> +
>  #if defined(CONFIG_USER_ONLY)
>      /* For usermode syscall translation.  */
>      int eabi;
> @@ -3264,6 +3277,21 @@ static inline bool isar_feature_aa64_fcma(const 
> ARMISARegisters *id)
>      return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, FCMA) != 0;
>  }
>
> +static inline bool isar_feature_aa64_pauth(const ARMISARegisters *id)
> +{
> +    /*
> +     * Note that while QEMU will only implement the architected algorithm
> +     * QARMA, and thus APA+GPA, the host cpu for kvm may use implementation
> +     * defined algorithms, and thus API+GPI, and this predicate controls
> +     * migration of the 128-bit keys.
> +     */
> +    return (id->id_aa64isar1 &
> +            (FIELD_DP64(0, ID_AA64ISAR1, APA, -1) |
> +             FIELD_DP64(0, ID_AA64ISAR1, API, -1) |
> +             FIELD_DP64(0, ID_AA64ISAR1, GPA, -1) |
> +             FIELD_DP64(0, ID_AA64ISAR1, GPI, -1))) != 0;
> +}

Hi Richard -- clang doesn't like the -1s here:

In file included from /home/petmay01/linaro/qemu-for-merges/disas.c:7:
/home/petmay01/linaro/qemu-for-merges/target/arm/cpu.h:3295:47: error:
implicit truncation from 'int
' to bitfield changes value from -1 to 15
[-Werror,-Wbitfield-constant-conversion]
            (FIELD_DP64(0, ID_AA64ISAR1, APA, -1) |
                                              ^~
/home/petmay01/linaro/qemu-for-merges/include/hw/registerfields.h:63:18:
note: expanded from macro '
FIELD_DP64'
    } v = { .v = val };                                                   \
                 ^~~

I'm going to change these to 0xf, which hopefully will be
sufficient to placate it.

thanks
-- PMM