[PATCH 07/37] KVM: arm/arm64: Add kvm_vcpu_load_sysregs and kvm_vcpu_put_sysregs

[Andrew Jones]

On Thu, Oct 12, 2017 at 12:41:11PM +0200, Christoffer Dall wrote:
> As we are about to move a buch of save/restore logic for VHE kernels to
> the load and put functions, we need some infrastructure to do this.
> 
> Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
> ---
>  arch/arm/include/asm/kvm_host.h   |  3 +++
>  arch/arm64/include/asm/kvm_host.h |  3 +++
>  arch/arm64/kvm/hyp/sysreg-sr.c    | 27 +++++++++++++++++++++++++++
>  virt/kvm/arm/arm.c                |  2 ++
>  4 files changed, 35 insertions(+)
> 
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index 1100170..13f8165 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -290,4 +290,7 @@ int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu,
>  int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu,
>  			       struct kvm_device_attr *attr);
>  
> +static inline void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) {}
> +static inline void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) {}
> +
>  #endif /* __ARM_KVM_HOST_H__ */
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 27305e7..7d3bfa7 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -383,4 +383,7 @@ static inline void __cpu_init_stage2(void)
>  		  "PARange is %d bits, unsupported configuration!", parange);
>  }
>  
> +void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu);
> +void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu);
> +
>  #endif /* __ARM64_KVM_HOST_H__ */
> diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
> index c54cc2a..b7438c8 100644
> --- a/arch/arm64/kvm/hyp/sysreg-sr.c
> +++ b/arch/arm64/kvm/hyp/sysreg-sr.c
> @@ -183,3 +183,30 @@ void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
>  	if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)
>  		write_sysreg(sysreg[DBGVCR32_EL2], dbgvcr32_el2);
>  }
> +
> +/**
> + * kvm_vcpu_load_sysregs - Load guest system register to physical CPU

system registers to the physical CPU

> + *
> + * @vcpu: The VCPU pointer
> + *
> + * If the kernel runs in EL2 then load the system register state for the VCPU
> + * for EL1 onto the physical CPU so that we can go back and foward between the

/foward/forth/

> + * VM and the hypervisor without switching all this state around.
> + */
> +void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu)
> +{
> +}
> +
> +/**
> + * kvm_vcpu_put_sysregs - Restore host system register state to physical CPU

system registers to the physical CPU

> + *
> + * @vcpu: The VCPU pointer
> + *
> + * If the kernel runs in EL2 and the physical register state belongs to the
> + * VCPU, then restore the system register state for the host for EL1 onto the
> + * physical CPU so that we can run userspace and other threads on this
> + * physical CPU.
> + */
> +void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu)
> +{
> +}
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index d495453..cf121b2 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -358,6 +358,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>  	kvm_arm_set_running_vcpu(vcpu);
>  	kvm_vgic_load(vcpu);
>  	kvm_timer_vcpu_load(vcpu);
> +	kvm_vcpu_load_sysregs(vcpu);
>  }
>  
>  void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
> @@ -365,6 +366,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
>  	if (vcpu->ioctl != KVM_RUN)
>  		return;
>  
> +	kvm_vcpu_put_sysregs(vcpu);
>  	kvm_timer_vcpu_put(vcpu);
>  	kvm_vgic_put(vcpu);
>  
> -- 
> 2.9.0
> 

I'm not sure this needs to be a separate patch, but it was a nice relaxing
review :-)

Reviewed-by: Andrew Jones <drjones at redhat.com>