[PATCH v2 6/6] RISCV: KVM: Add sstateen0 to ONE_REG

[Andrew Jones]

On Fri, Jul 21, 2023 at 01:24:39PM +0530, Mayuresh Chitale wrote:
> Add support for sstateen0 CSR to the ONE_REG interface to allow its
> access from user space.
> 
> Signed-off-by: Mayuresh Chitale <mchitale at ventanamicro.com>
> ---
>  arch/riscv/include/uapi/asm/kvm.h |  9 +++++++
>  arch/riscv/kvm/vcpu.c             | 40 +++++++++++++++++++++++++++++++
>  2 files changed, 49 insertions(+)
> 
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index 74c7f42de29d..bdddfb20299a 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -93,6 +93,11 @@ struct kvm_riscv_aia_csr {
>  	unsigned long iprio2h;
>  };
>  
> +/* Smstateen CSR for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
> +struct kvm_riscv_smstateen_csr {
> +	unsigned long sstateen0;
> +};
> +
>  /* TIMER registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
>  struct kvm_riscv_timer {
>  	__u64 frequency;
> @@ -173,10 +178,14 @@ enum KVM_RISCV_SBI_EXT_ID {
>  #define KVM_REG_RISCV_CSR		(0x03 << KVM_REG_RISCV_TYPE_SHIFT)
>  #define KVM_REG_RISCV_CSR_GENERAL	(0x0 << KVM_REG_RISCV_SUBTYPE_SHIFT)
>  #define KVM_REG_RISCV_CSR_AIA		(0x1 << KVM_REG_RISCV_SUBTYPE_SHIFT)
> +#define KVM_REG_RISCV_CSR_SMSTATEEN	(0x2 << KVM_REG_RISCV_SUBTYPE_SHIFT)
> +
>  #define KVM_REG_RISCV_CSR_REG(name)	\
>  		(offsetof(struct kvm_riscv_csr, name) / sizeof(unsigned long))
>  #define KVM_REG_RISCV_CSR_AIA_REG(name)	\
>  	(offsetof(struct kvm_riscv_aia_csr, name) / sizeof(unsigned long))
> +#define KVM_REG_RISCV_CSR_SMSTATEEN_REG(name)	\
> +	(offsetof(struct kvm_riscv_smstateen_csr, name) / sizeof(unsigned long))
>  
>  /* Timer registers are mapped as type 4 */
>  #define KVM_REG_RISCV_TIMER		(0x04 << KVM_REG_RISCV_TYPE_SHIFT)
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index ae750decbefe..af7549374c4b 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -507,6 +507,34 @@ static int kvm_riscv_vcpu_general_get_csr(struct kvm_vcpu *vcpu,
>  	return 0;
>  }
>  
> +static inline int kvm_riscv_vcpu_smstateen_set_csr(struct kvm_vcpu *vcpu,
> +						   unsigned long reg_num,
> +						   unsigned long reg_val)
> +{
> +	struct kvm_vcpu_smstateen_csr *csr = &vcpu->arch.smstateen_csr;
> +
> +	if (reg_num >= sizeof(struct kvm_riscv_smstateen_csr) /
> +	    sizeof(unsigned long))
> +		return -EINVAL;
> +
> +	((unsigned long *)csr)[reg_num] = reg_val;
> +	return 0;
> +}
> +
> +static int kvm_riscv_vcpu_smstateen_get_csr(struct kvm_vcpu *vcpu,
> +					    unsigned long reg_num,
> +					    unsigned long *out_val)
> +{
> +	struct kvm_vcpu_smstateen_csr *csr = &vcpu->arch.smstateen_csr;
> +
> +	if (reg_num >= sizeof(struct kvm_riscv_smstateen_csr) /
> +	    sizeof(unsigned long))
> +		return -EINVAL;
> +
> +	*out_val = ((unsigned long *)csr)[reg_num];
> +	return 0;
> +}
> +
>  static inline int kvm_riscv_vcpu_general_set_csr(struct kvm_vcpu *vcpu,
>  						 unsigned long reg_num,
>  						 unsigned long reg_val)
> @@ -552,6 +580,12 @@ static int kvm_riscv_vcpu_get_reg_csr(struct kvm_vcpu *vcpu,
>  	case KVM_REG_RISCV_CSR_AIA:
>  		rc = kvm_riscv_vcpu_aia_get_csr(vcpu, reg_num, &reg_val);
>  		break;
> +	case KVM_REG_RISCV_CSR_SMSTATEEN:
> +		rc = -EINVAL;
> +		if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN))
> +			rc = kvm_riscv_vcpu_smstateen_get_csr(vcpu, reg_num,
> +							      &reg_val);
> +		break;
>  	default:
>  		rc = -EINVAL;
>  		break;
> @@ -591,6 +625,12 @@ static int kvm_riscv_vcpu_set_reg_csr(struct kvm_vcpu *vcpu,
>  	case KVM_REG_RISCV_CSR_AIA:
>  		rc = kvm_riscv_vcpu_aia_set_csr(vcpu, reg_num, reg_val);
>  		break;
> +	case KVM_REG_RISCV_CSR_SMSTATEEN:
> +		rc = -EINVAL;
> +		if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN))
> +			rc = kvm_riscv_vcpu_smstateen_set_csr(vcpu, reg_num,
> +							      reg_val);
> +		break;
>  	default:
>  		rc = -EINVAL;
>  		break;
> -- 
> 2.34.1
>

The EINVAL's will get changed to ENOENT's with the get/set-one-reg error
code rework that's coming after get-reg-list lands, but for now I guess
it makes sense to leave them consistent with the others.

Reviewed-by: Andrew Jones <ajones at ventanamicro.com>