[RFC PATCH v2 09/23] KVM: arm64: Propagate vcpu into read_id_reg()

[alex.bennee@linaro.org (Alex Bennée)]

Dave Martin <Dave.Martin@arm.com> writes:

> Architecture features that are conditionally visible to the guest
> will require run-time checks in the ID register accessor functions.
> In particular, read_id_reg() will need to perform checks in order
> to generate the correct emulated value for certain ID register
> fields such as ID_AA64PFR0_EL1.SVE for example.
>
> This patch propagates vcpu into read_id_reg() so that future
> patches can add run-time checks on the guest configuration here.
>
> For now, there is no functional change.
>
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>

Reviewed-by: Alex Benn?e <alex.bennee@linaro.org>

> ---
>  arch/arm64/kvm/sys_regs.c | 23 +++++++++++++----------
>  1 file changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 22fbbdb..0dfd064 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1029,7 +1029,8 @@ static bool access_cntp_cval(struct kvm_vcpu *vcpu,
>  }
>
>  /* Read a sanitised cpufeature ID register by sys_reg_desc */
> -static u64 read_id_reg(struct sys_reg_desc const *r, bool raz)
> +static u64 read_id_reg(const struct kvm_vcpu *vcpu,
> +		struct sys_reg_desc const *r, bool raz)
>  {
>  	u32 id = sys_reg((u32)r->Op0, (u32)r->Op1,
>  			 (u32)r->CRn, (u32)r->CRm, (u32)r->Op2);
> @@ -1060,7 +1061,7 @@ static bool __access_id_reg(struct kvm_vcpu *vcpu,
>  	if (p->is_write)
>  		return write_to_read_only(vcpu, p, r);
>
> -	p->regval = read_id_reg(r, raz);
> +	p->regval = read_id_reg(vcpu, r, raz);
>  	return true;
>  }
>
> @@ -1089,16 +1090,18 @@ static u64 sys_reg_to_index(const struct sys_reg_desc *reg);
>   * are stored, and for set_id_reg() we don't allow the effective value
>   * to be changed.
>   */
> -static int __get_id_reg(const struct sys_reg_desc *rd, void __user *uaddr,
> +static int __get_id_reg(const struct kvm_vcpu *vcpu,
> +			const struct sys_reg_desc *rd, void __user *uaddr,
>  			bool raz)
>  {
>  	const u64 id = sys_reg_to_index(rd);
> -	const u64 val = read_id_reg(rd, raz);
> +	const u64 val = read_id_reg(vcpu, rd, raz);
>
>  	return reg_to_user(uaddr, &val, id);
>  }
>
> -static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr,
> +static int __set_id_reg(const struct kvm_vcpu *vcpu,
> +			const struct sys_reg_desc *rd, void __user *uaddr,
>  			bool raz)
>  {
>  	const u64 id = sys_reg_to_index(rd);
> @@ -1110,7 +1113,7 @@ static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr,
>  		return err;
>
>  	/* This is what we mean by invariant: you can't change it. */
> -	if (val != read_id_reg(rd, raz))
> +	if (val != read_id_reg(vcpu, rd, raz))
>  		return -EINVAL;
>
>  	return 0;
> @@ -1119,25 +1122,25 @@ static int __set_id_reg(const struct sys_reg_desc *rd, void __user *uaddr,
>  static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>  		      const struct kvm_one_reg *reg, void __user *uaddr)
>  {
> -	return __get_id_reg(rd, uaddr, false);
> +	return __get_id_reg(vcpu, rd, uaddr, false);
>  }
>
>  static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>  		      const struct kvm_one_reg *reg, void __user *uaddr)
>  {
> -	return __set_id_reg(rd, uaddr, false);
> +	return __set_id_reg(vcpu, rd, uaddr, false);
>  }
>
>  static int get_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>  			  const struct kvm_one_reg *reg, void __user *uaddr)
>  {
> -	return __get_id_reg(rd, uaddr, true);
> +	return __get_id_reg(vcpu, rd, uaddr, true);
>  }
>
>  static int set_raz_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
>  			  const struct kvm_one_reg *reg, void __user *uaddr)
>  {
> -	return __set_id_reg(rd, uaddr, true);
> +	return __set_id_reg(vcpu, rd, uaddr, true);
>  }
>
>  /* sys_reg_desc initialiser for known cpufeature ID registers */


--
Alex Benn?e