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

Andre Przywara
2019-05-31T17:04:48Z

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