Re: [Qemu-devel] [PATCH 06/13] target/arm/kvm: max cpu: Enable SVE when available

[Auger Eric]

Hi Drew,

On 5/12/19 10:36 AM, Andrew Jones wrote:
> Enable SVE in the KVM guest when the 'max' cpu type is configured
> and KVM supports it. KVM SVE requires use of the new finalize
> vcpu ioctl, so we add that now too.
> 
> Signed-off-by: Andrew Jones <address@hidden>
> ---
>  target/arm/cpu64.c   |  1 +
>  target/arm/kvm.c     |  5 +++++
>  target/arm/kvm64.c   | 16 +++++++++++++++-
>  target/arm/kvm_arm.h | 12 ++++++++++++
>  4 files changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
> index 228906f26786..6c19ef6837d5 100644
> --- a/target/arm/cpu64.c
> +++ b/target/arm/cpu64.c
> @@ -292,6 +292,7 @@ static void aarch64_max_initfn(Object *obj)
>  
>      if (kvm_enabled()) {
>          kvm_arm_set_cpu_features_from_host(cpu);
> +        cpu->sve_max_vq = ARM_MAX_VQ;
same line in the !kvm_enabled path. Maybe you can set the sve_max_vq
field in a subsequent patch and just introduce the finalize and
capability checking in that patch?
>      } else {
>          uint64_t t;
>          uint32_t u;
> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index 599563461264..c51db4229d0f 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -50,6 +50,11 @@ int kvm_arm_vcpu_init(CPUState *cs)
>      return kvm_vcpu_ioctl(cs, KVM_ARM_VCPU_INIT, &init);
>  }
>  
> +int kvm_arm_vcpu_finalize(CPUState *cs, int feature)
> +{
> +    return kvm_vcpu_ioctl(cs, KVM_ARM_VCPU_FINALIZE, &feature);
> +}
> +
>  void kvm_arm_init_serror_injection(CPUState *cs)
>  {
>      cap_has_inject_serror_esr = kvm_check_extension(cs->kvm_state,
> diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
> index 86362f4cd7d0..c2d92df75353 100644
> --- a/target/arm/kvm64.c
> +++ b/target/arm/kvm64.c
> @@ -622,13 +622,20 @@ int kvm_arch_init_vcpu(CPUState *cs)
>          cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_EL1_32BIT;
>      }
>      if (!kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_PMU_V3)) {
> -            cpu->has_pmu = false;
> +        cpu->has_pmu = false;
nit: maybe document this unrelated indent fix in the commit msg?
>      }
>      if (cpu->has_pmu) {
>          cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_PMU_V3;
>      } else {
>          unset_feature(&env->features, ARM_FEATURE_PMU);
>      }
> +    if (cpu->sve_max_vq) {
> +        if (!kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_SVE)) {
> +            cpu->sve_max_vq = 0;
> +        } else {
> +            cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_SVE;
> +        }
> +    }
>  
>      /* Do KVM_ARM_VCPU_INIT ioctl */
>      ret = kvm_arm_vcpu_init(cs);
> @@ -636,6 +643,13 @@ int kvm_arch_init_vcpu(CPUState *cs)
>          return ret;
>      }
>  
> +    if (cpu->sve_max_vq) {
> +        ret = kvm_arm_vcpu_finalize(cs, KVM_ARM_VCPU_SVE);
> +        if (ret) {
> +            return ret;
> +        }
> +    }
> +
>      /*
>       * When KVM is in use, PSCI is emulated in-kernel and not by qemu.
>       * Currently KVM has its own idea about MPIDR assignment, so we
> diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
> index 2a07333c615f..c488ec3ab410 100644
> --- a/target/arm/kvm_arm.h
> +++ b/target/arm/kvm_arm.h
> @@ -27,6 +27,18 @@
>   */
>  int kvm_arm_vcpu_init(CPUState *cs);
>  
> +/**
> + * kvm_arm_vcpu_finalize
> + * @cs: CPUState
> + * @feature: int
feature bitmap or bit?
> + *
> + * Finalizes the configuration of the specified VCPU feature
> + * by invoking the KVM_ARM_VCPU_FINALIZE ioctl.
> + *
> + * Returns: 0 if success else < 0 error code
> + */
> +int kvm_arm_vcpu_finalize(CPUState *cs, int feature);
> +
>  /**
>   * kvm_arm_register_device:
>   * @mr: memory region for this device
>