Re: [PATCH v3 06/18] arm/arm64: KVM: Add smccc accessors to PSCI code

[Christoffer Dall <christoffer.dall@linaro.org>]

On Thu, Feb 01, 2018 at 11:46:45AM +0000, Marc Zyngier wrote:
> Instead of open coding the accesses to the various registers,
> let's add explicit SMCCC accessors.
> 

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  virt/kvm/arm/psci.c | 52 ++++++++++++++++++++++++++++++++++++++++++----------
>  1 file changed, 42 insertions(+), 10 deletions(-)
> 
> diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
> index 999f94d6bb98..c41553d35110 100644
> --- a/virt/kvm/arm/psci.c
> +++ b/virt/kvm/arm/psci.c
> @@ -32,6 +32,38 @@
>  
>  #define AFFINITY_MASK(level)	~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
>  
> +static u32 smccc_get_function(struct kvm_vcpu *vcpu)
> +{
> +	return vcpu_get_reg(vcpu, 0);
> +}
> +
> +static unsigned long smccc_get_arg1(struct kvm_vcpu *vcpu)
> +{
> +	return vcpu_get_reg(vcpu, 1);
> +}
> +
> +static unsigned long smccc_get_arg2(struct kvm_vcpu *vcpu)
> +{
> +	return vcpu_get_reg(vcpu, 2);
> +}
> +
> +static unsigned long smccc_get_arg3(struct kvm_vcpu *vcpu)
> +{
> +	return vcpu_get_reg(vcpu, 3);
> +}
> +
> +static void smccc_set_retval(struct kvm_vcpu *vcpu,
> +			     unsigned long a0,
> +			     unsigned long a1,
> +			     unsigned long a2,
> +			     unsigned long a3)
> +{
> +	vcpu_set_reg(vcpu, 0, a0);
> +	vcpu_set_reg(vcpu, 1, a1);
> +	vcpu_set_reg(vcpu, 2, a2);
> +	vcpu_set_reg(vcpu, 3, a3);
> +}
> +
>  static unsigned long psci_affinity_mask(unsigned long affinity_level)
>  {
>  	if (affinity_level <= 3)
> @@ -77,7 +109,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>  	unsigned long context_id;
>  	phys_addr_t target_pc;
>  
> -	cpu_id = vcpu_get_reg(source_vcpu, 1) & MPIDR_HWID_BITMASK;
> +	cpu_id = smccc_get_arg1(source_vcpu) & MPIDR_HWID_BITMASK;
>  	if (vcpu_mode_is_32bit(source_vcpu))
>  		cpu_id &= ~((u32) 0);
>  
> @@ -96,8 +128,8 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>  			return PSCI_RET_INVALID_PARAMS;
>  	}
>  
> -	target_pc = vcpu_get_reg(source_vcpu, 2);
> -	context_id = vcpu_get_reg(source_vcpu, 3);
> +	target_pc = smccc_get_arg2(source_vcpu);
> +	context_id = smccc_get_arg3(source_vcpu);
>  
>  	kvm_reset_vcpu(vcpu);
>  
> @@ -116,7 +148,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>  	 * NOTE: We always update r0 (or x0) because for PSCI v0.1
>  	 * the general puspose registers are undefined upon CPU_ON.
>  	 */
> -	vcpu_set_reg(vcpu, 0, context_id);
> +	smccc_set_retval(vcpu, context_id, 0, 0, 0);
>  	vcpu->arch.power_off = false;
>  	smp_mb();		/* Make sure the above is visible */
>  
> @@ -136,8 +168,8 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
>  	struct kvm *kvm = vcpu->kvm;
>  	struct kvm_vcpu *tmp;
>  
> -	target_affinity = vcpu_get_reg(vcpu, 1);
> -	lowest_affinity_level = vcpu_get_reg(vcpu, 2);
> +	target_affinity = smccc_get_arg1(vcpu);
> +	lowest_affinity_level = smccc_get_arg2(vcpu);
>  
>  	/* Determine target affinity mask */
>  	target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
> @@ -210,7 +242,7 @@ int kvm_psci_version(struct kvm_vcpu *vcpu)
>  static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
>  {
>  	struct kvm *kvm = vcpu->kvm;
> -	unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0);
> +	u32 psci_fn = smccc_get_function(vcpu);
>  	unsigned long val;
>  	int ret = 1;
>  
> @@ -277,14 +309,14 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
>  		break;
>  	}
>  
> -	vcpu_set_reg(vcpu, 0, val);
> +	smccc_set_retval(vcpu, val, 0, 0, 0);
>  	return ret;
>  }
>  
>  static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
>  {
>  	struct kvm *kvm = vcpu->kvm;
> -	unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0);
> +	u32 psci_fn = smccc_get_function(vcpu);
>  	unsigned long val;
>  
>  	switch (psci_fn) {
> @@ -302,7 +334,7 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
>  		break;
>  	}
>  
> -	vcpu_set_reg(vcpu, 0, val);
> +	smccc_set_retval(vcpu, val, 0, 0, 0);
>  	return 1;
>  }
>  
> -- 
> 2.14.2
>