Re: [Qemu-devel] [PATCH v2 10/14] target/arm/kvm64: Add kvm_arch_get/put_sve

[Auger Eric <eric.auger@redhat.com>]

Hi,

On 6/21/19 6:34 PM, Andrew Jones wrote:
> These are the SVE equivalents to kvm_arch_get/put_fpsimd. Note, the
> swabbing is different than it is for fpsmid because the vector format
> is a little-endian stream of words.

some cosmetic changes besides Richard's comments
> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  target/arm/kvm64.c | 135 +++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 131 insertions(+), 4 deletions(-)
> 
> diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
> index a2485d447e6a..706541327491 100644
> --- a/target/arm/kvm64.c
> +++ b/target/arm/kvm64.c
> @@ -673,11 +673,12 @@ int kvm_arch_destroy_vcpu(CPUState *cs)
>  bool kvm_arm_reg_syncs_via_cpreg_list(uint64_t regidx)
>  {
>      /* Return true if the regidx is a register we should synchronize
> -     * via the cpreg_tuples array (ie is not a core reg we sync by
> -     * hand in kvm_arch_get/put_registers())
> +     * via the cpreg_tuples array (ie is not a core or sve reg that
> +     * we sync by hand in kvm_arch_get/put_registers())
>       */
>      switch (regidx & KVM_REG_ARM_COPROC_MASK) {
>      case KVM_REG_ARM_CORE:
> +    case KVM_REG_ARM64_SVE:
>          return false;
>      default:
>          return true;
> @@ -763,6 +764,70 @@ static int kvm_arch_put_fpsimd(CPUState *cs)
>      return 0;
>  }
>  
> +/*
> + * If ARM_MAX_VQ is increased to be greater than 16, then we can no
> + * longer hard code slices to 1 in kvm_arch_put/get_sve().
> + */
> +QEMU_BUILD_BUG_ON(ARM_MAX_VQ > 16);
if the code is ready to support slices, I guess you could have a define
and compute the slice number from ARM_MAX_VQ?
> +
> +static int kvm_arch_put_sve(CPUState *cs)
> +{
> +    ARMCPU *cpu = ARM_CPU(cs);
> +    CPUARMState *env = &cpu->env;
> +    struct kvm_one_reg reg;
> +    int slices = 1;
> +    int i, n, ret;
> +
> +    for (i = 0; i < slices; i++) {
> +        for (n = 0; n < KVM_ARM64_SVE_NUM_ZREGS; n++) {
> +            uint64_t *q = aa64_vfp_qreg(env, n);
> +#ifdef HOST_WORDS_BIGENDIAN
> +            uint64_t d[ARM_MAX_VQ * 2];
> +            int j;
line to be added
> +            for (j = 0; j < cpu->sve_max_vq * 2; j++) {
> +                d[j] = bswap64(q[j]);
> +            }
> +            reg.addr = (uintptr_t)d;
> +#else
> +            reg.addr = (uintptr_t)q;
> +#endif
> +            reg.id = KVM_REG_ARM64_SVE_ZREG(n, i);
> +            ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
> +            if (ret) {
> +                return ret;
> +            }
> +        }
> +
> +        for (n = 0; n < KVM_ARM64_SVE_NUM_PREGS; n++) {
> +            uint64_t *q = &env->vfp.pregs[n].p[0];
> +#ifdef HOST_WORDS_BIGENDIAN
> +            uint64_t d[ARM_MAX_VQ * 2 / 8];
> +            int j;
line
> +            for (j = 0; j < cpu->sve_max_vq * 2 / 8; j++) {
> +                d[j] = bswap64(q[j]);
> +            }
> +            reg.addr = (uintptr_t)d;
> +#else
> +            reg.addr = (uintptr_t)q;
> +#endif
> +            reg.id = KVM_REG_ARM64_SVE_PREG(n, i);
> +            ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
> +            if (ret) {
> +                return ret;
> +            }
> +        }
> +
> +        reg.addr = (uintptr_t)&env->vfp.pregs[FFR_PRED_NUM].p[0];
> +        reg.id = KVM_REG_ARM64_SVE_FFR(i);
> +        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
> +        if (ret) {
> +            return ret;
> +        }
> +    }
> +
> +    return 0;
> +}
> +
>  int kvm_arch_put_registers(CPUState *cs, int level)
>  {
>      struct kvm_one_reg reg;
> @@ -857,7 +922,11 @@ int kvm_arch_put_registers(CPUState *cs, int level)
>          }
>      }
>  
> -    ret = kvm_arch_put_fpsimd(cs);
> +    if (!cpu->sve_max_vq) {
> +        ret = kvm_arch_put_fpsimd(cs);
> +    } else {
> +        ret = kvm_arch_put_sve(cs);
> +    }
>      if (ret) {
>          return ret;
>      }
> @@ -920,6 +989,60 @@ static int kvm_arch_get_fpsimd(CPUState *cs)
>      return 0;
>  }
>  
> +static int kvm_arch_get_sve(CPUState *cs)
> +{
> +    ARMCPU *cpu = ARM_CPU(cs);
> +    CPUARMState *env = &cpu->env;
> +    struct kvm_one_reg reg;
> +    int slices = 1;
> +    int i, n, ret;
> +
> +    for (i = 0; i < slices; i++) {
> +        for (n = 0; n < KVM_ARM64_SVE_NUM_ZREGS; n++) {
> +            uint64_t *q = aa64_vfp_qreg(env, n);
extra line needed
> +            reg.id = KVM_REG_ARM64_SVE_ZREG(n, i);
> +            reg.addr = (uintptr_t)q;
> +            ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
> +            if (ret) {
> +                return ret;
> +            } else {> +#ifdef HOST_WORDS_BIGENDIAN
> +                int j;
line
> +                for (j = 0; j < cpu->sve_max_vq * 2; j++) {
> +                    q[j] = bswap64(q[j]);
> +                }
> +#endif
> +            }
> +        }
> +
> +        for (n = 0; n < KVM_ARM64_SVE_NUM_PREGS; n++) {
> +            uint64_t *q = &env->vfp.pregs[n].p[0];
extra line needed
> +            reg.id = KVM_REG_ARM64_SVE_PREG(n, i);
> +            reg.addr = (uintptr_t)q;
> +            ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
> +            if (ret) {
> +                return ret;
> +            } else {> +#ifdef HOST_WORDS_BIGENDIAN
> +                int j;
line
> +                for (j = 0; j < cpu->sve_max_vq * 2 / 8; j++) {
> +                    q[j] = bswap64(q[j]);
> +                }
> +#endif
> +            }
> +        }
> +
> +        reg.addr = (uintptr_t)&env->vfp.pregs[FFR_PRED_NUM].p[0];
> +        reg.id = KVM_REG_ARM64_SVE_FFR(i);
> +        ret = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
> +        if (ret) {
> +            return ret;
> +        }
> +    }
> +
> +    return 0;
> +}
> +
>  int kvm_arch_get_registers(CPUState *cs)
>  {
>      struct kvm_one_reg reg;
> @@ -1014,7 +1137,11 @@ int kvm_arch_get_registers(CPUState *cs)
>          env->spsr = env->banked_spsr[i];
>      }
>  
> -    ret = kvm_arch_get_fpsimd(cs);
> +    if (!cpu->sve_max_vq) {
> +        ret = kvm_arch_get_fpsimd(cs);
> +    } else {
> +        ret = kvm_arch_get_sve(cs);
> +    }
>      if (ret) {
>          return ret;
>      }
> 


Thanks

Eric