[PATCH 07/19] KVM: arm64: vgic-v3: Simplify vgic_v3_has_cpu_sysregs_attr()

[Oliver Upton]

On Wed, Jul 06, 2022 at 05:42:52PM +0100, Marc Zyngier wrote:
> Finding out whether a sysreg exists has little to do with that
> register being accessed, so drop the is_write parameter.
> 
> Also, the reg pointer is completely unused, and we're better off
> just passing the attr pointer to the function.
> 
> This result in a small cleanup of the calling site, with a new
> helper converting the vGIC view of a sysreg into the canonical
> one (this is purely cosmetic, as the encoding is the same).
> 
> Signed-off-by: Marc Zyngier <maz at kernel.org>

Reviewed-by: Oliver Upton <oliver.upton at linux.dev>

> ---
>  arch/arm64/kvm/vgic-sys-reg-v3.c   | 14 ++++++++++----
>  arch/arm64/kvm/vgic/vgic-mmio-v3.c |  8 ++------
>  arch/arm64/kvm/vgic/vgic.h         |  3 +--
>  3 files changed, 13 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
> index 644acda33c7c..85a5e1d15e9f 100644
> --- a/arch/arm64/kvm/vgic-sys-reg-v3.c
> +++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
> @@ -260,12 +260,18 @@ static const struct sys_reg_desc gic_v3_icc_reg_descs[] = {
>  	{ SYS_DESC(SYS_ICC_IGRPEN1_EL1), access_gic_grpen1 },
>  };
>  
> -int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> -				u64 *reg)
> +static u64 attr_to_id(u64 attr)
>  {
> -	u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
> +	return ARM64_SYS_REG(FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_OP0_MASK, attr),
> +			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_OP1_MASK, attr),
> +			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_CRN_MASK, attr),
> +			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_CRM_MASK, attr),
> +			     FIELD_GET(KVM_REG_ARM_VGIC_SYSREG_OP2_MASK, attr));
> +}
>  
> -	if (get_reg_by_id(sysreg, gic_v3_icc_reg_descs,
> +int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
> +{
> +	if (get_reg_by_id(attr_to_id(attr->attr), gic_v3_icc_reg_descs,
>  			  ARRAY_SIZE(gic_v3_icc_reg_descs)))
>  		return 0;
>  
> diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
> index f15e29cc63ce..a2ff73899976 100644
> --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
> +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
> @@ -986,12 +986,8 @@ int vgic_v3_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
>  		iodev.base_addr = 0;
>  		break;
>  	}
> -	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS: {
> -		u64 reg, id;
> -
> -		id = (attr->attr & KVM_DEV_ARM_VGIC_SYSREG_INSTR_MASK);
> -		return vgic_v3_has_cpu_sysregs_attr(vcpu, 0, id, &reg);
> -	}
> +	case KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS:
> +		return vgic_v3_has_cpu_sysregs_attr(vcpu, attr);
>  	default:
>  		return -ENXIO;
>  	}
> diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
> index 4c6bdd321faa..ffc2d3c81b28 100644
> --- a/arch/arm64/kvm/vgic/vgic.h
> +++ b/arch/arm64/kvm/vgic/vgic.h
> @@ -247,8 +247,7 @@ int vgic_v3_redist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>  			 int offset, u32 *val);
>  int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>  			 u64 id, u64 *val);
> -int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> -				u64 *reg);
> +int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
>  int vgic_v3_line_level_info_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>  				    u32 intid, u64 *val);
>  int kvm_register_vgic_device(unsigned long type);
> -- 
> 2.34.1
>