Re: [PATCH kvmtool v3 6/9] arm/arm64: Factor out ptrauth vcpu feature setup

[Andre Przywara <andre.przywara@arm.com>]

On Thu, 30 May 2019 16:13:11 +0100
Dave Martin <Dave.Martin@arm.com> wrote:

> In the interest of readability, factor out the vcpu feature setup
> for ptrauth into a separate function.
> 
> Also, because aarch32 doesn't have this feature or the related
> command line options anyway, move the actual code into aarch64/.
> 
> Since ARM_VCPU_PTRAUTH_FEATURE is only there to make the ptrauth
> feature setup code compile on arm, it is no longer needed: inline
> and remove it.

I am not sure this is useful as a separate patch, so can we just merge this into 5/9?

Cheers,
Andre.

> 
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> ---
>  arm/aarch32/include/kvm/kvm-cpu-arch.h |  3 ++-
>  arm/aarch64/include/kvm/kvm-cpu-arch.h |  3 +--
>  arm/aarch64/kvm-cpu.c                  | 22 ++++++++++++++++++++++
>  arm/kvm-cpu.c                          | 12 +-----------
>  4 files changed, 26 insertions(+), 14 deletions(-)
> 
> diff --git a/arm/aarch32/include/kvm/kvm-cpu-arch.h b/arm/aarch32/include/kvm/kvm-cpu-arch.h
> index 3ec6f03..01983f0 100644
> --- a/arm/aarch32/include/kvm/kvm-cpu-arch.h
> +++ b/arm/aarch32/include/kvm/kvm-cpu-arch.h
> @@ -13,6 +13,7 @@
>  #define ARM_CPU_ID		0, 0, 0
>  #define ARM_CPU_ID_MPIDR	5
>  
> -#define ARM_VCPU_PTRAUTH_FEATURE	0
> +static inline void kvm_cpu__select_features(struct kvm *kvm,
> +					    struct kvm_vcpu_init *init) { }
>  
>  #endif /* KVM__KVM_CPU_ARCH_H */
> diff --git a/arm/aarch64/include/kvm/kvm-cpu-arch.h b/arm/aarch64/include/kvm/kvm-cpu-arch.h
> index 9fa99fb..e6875fc 100644
> --- a/arm/aarch64/include/kvm/kvm-cpu-arch.h
> +++ b/arm/aarch64/include/kvm/kvm-cpu-arch.h
> @@ -17,7 +17,6 @@
>  #define ARM_CPU_CTRL		3, 0, 1, 0
>  #define ARM_CPU_CTRL_SCTLR_EL1	0
>  
> -#define ARM_VCPU_PTRAUTH_FEATURE	((1UL << KVM_ARM_VCPU_PTRAUTH_ADDRESS) \
> -					| (1UL << KVM_ARM_VCPU_PTRAUTH_GENERIC))
> +void kvm_cpu__select_features(struct kvm *kvm, struct kvm_vcpu_init *init);
>  
>  #endif /* KVM__KVM_CPU_ARCH_H */
> diff --git a/arm/aarch64/kvm-cpu.c b/arm/aarch64/kvm-cpu.c
> index 0aaefaf..d3c32e0 100644
> --- a/arm/aarch64/kvm-cpu.c
> +++ b/arm/aarch64/kvm-cpu.c
> @@ -128,6 +128,28 @@ static void reset_vcpu_aarch64(struct kvm_cpu *vcpu)
>  	}
>  }
>  
> +static void select_ptrauth_feature(struct kvm *kvm, struct kvm_vcpu_init *init)
> +{
> +	/* Check Pointer Authentication command line arguments. */
> +	if (kvm->cfg.arch.enable_ptrauth && kvm->cfg.arch.disable_ptrauth)
> +		die("Both enable-ptrauth and disable-ptrauth option cannot be present");
> +	/*
> +	 * Always enable Pointer Authentication if system supports
> +	 * this extension unless disable-ptrauth option is present.
> +	 */
> +	if (kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS) &&
> +	    kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC) &&
> +	    !kvm->cfg.arch.disable_ptrauth) {
> +		init->features[0] |= 1UL << KVM_ARM_VCPU_PTRAUTH_ADDRESS;
> +		init->features[0] |= 1UL << KVM_ARM_VCPU_PTRAUTH_GENERIC;
> +	}
> +}
> +
> +void kvm_cpu__select_features(struct kvm *kvm, struct kvm_vcpu_init *init)
> +{
> +	select_ptrauth_feature(kvm, init);
> +}
> +
>  void kvm_cpu__reset_vcpu(struct kvm_cpu *vcpu)
>  {
>  	if (vcpu->kvm->cfg.arch.aarch32_guest)
> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
> index acd1d5f..764fb05 100644
> --- a/arm/kvm-cpu.c
> +++ b/arm/kvm-cpu.c
> @@ -68,17 +68,7 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
>  		vcpu_init.features[0] |= (1UL << KVM_ARM_VCPU_PSCI_0_2);
>  	}
>  
> -	/* Check Pointer Authentication command line arguments. */
> -	if (kvm->cfg.arch.enable_ptrauth && kvm->cfg.arch.disable_ptrauth)
> -		die("Both enable-ptrauth and disable-ptrauth option cannot be present");
> -	/*
> -	 * Always enable Pointer Authentication if system supports
> -	 * this extension unless disable-ptrauth option is present.
> -	 */
> -	if (kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS) &&
> -	    kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC) &&
> -	    !kvm->cfg.arch.disable_ptrauth)
> -			vcpu_init.features[0] |= ARM_VCPU_PTRAUTH_FEATURE;
> +	kvm_cpu__select_features(kvm, &vcpu_init);
>  
>  	/*
>  	 * If the preferred target ioctl is successful then

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