Re: [PATCH v3 4/5] KVM: arm64: Introduce find_reg_by_id()

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

On 04/09/15 13:40, Pavel Fedin wrote:
> In order to implement vGICv3 CPU interface access, we will need to perform
> table lookup of system registers. We would need both index_to_params() and
> find_reg() exported for that purpose, but instead we export a single
> function which combines them both.
> 
> Signed-off-by: Pavel Fedin <p.fedin@samsung.com>

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

> ---
>  arch/arm64/kvm/sys_regs.c | 22 +++++++++++++++-------
>  arch/arm64/kvm/sys_regs.h |  4 ++++
>  2 files changed, 19 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index fe6b517..21403fa 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1283,6 +1283,17 @@ static bool index_to_params(u64 id, struct sys_reg_params *params)
>  	}
>  }
>  
> +const struct sys_reg_desc *find_reg_by_id(u64 id,
> +					  struct sys_reg_params *params,
> +					  const struct sys_reg_desc table[],
> +					  unsigned int num)
> +{
> +	if (!index_to_params(id, params))
> +		return NULL;
> +
> +	return find_reg(params, table, num);
> +}
> +
>  /* Decode an index value, and find the sys_reg_desc entry. */
>  static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
>  						    u64 id)
> @@ -1410,10 +1421,8 @@ static int get_invariant_sys_reg(u64 id, void __user *uaddr)
>  	struct sys_reg_params params;
>  	const struct sys_reg_desc *r;
>  
> -	if (!index_to_params(id, &params))
> -		return -ENOENT;
> -
> -	r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
> +	r = find_reg_by_id(id, &params, invariant_sys_regs,
> +			   ARRAY_SIZE(invariant_sys_regs));
>  	if (!r)
>  		return -ENOENT;
>  
> @@ -1427,9 +1436,8 @@ static int set_invariant_sys_reg(u64 id, void __user *uaddr)
>  	int err;
>  	u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
>  
> -	if (!index_to_params(id, &params))
> -		return -ENOENT;
> -	r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
> +	r = find_reg_by_id(id, &params, invariant_sys_regs,
> +			   ARRAY_SIZE(invariant_sys_regs));
>  	if (!r)
>  		return -ENOENT;
>  
> diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> index 3267518..0646108 100644
> --- a/arch/arm64/kvm/sys_regs.h
> +++ b/arch/arm64/kvm/sys_regs.h
> @@ -136,6 +136,10 @@ static inline int cmp_sys_reg(const struct sys_reg_desc *i1,
>  	return i1->Op2 - i2->Op2;
>  }
>  
> +const struct sys_reg_desc *find_reg_by_id(u64 id,
> +					  struct sys_reg_params *params,
> +					  const struct sys_reg_desc table[],
> +					  unsigned int num);
>  
>  #define Op0(_x) 	.Op0 = _x
>  #define Op1(_x) 	.Op1 = _x
>