Subject: [PATCH 10/18] KVM: ARM64: Add reset and access handlers for PMCCNTR_EL0 register

From: [email-masked] (Christoffer Dall)
Date: Fri, 17 Jul 2015 16:42:27 +0200

On Mon, Jul 06, 2015 at 10:17:40AM +0800, shannon.zhao at linaro.org wrote:
> From: Shannon Zhao <[email-masked]>
> 
> Since the reset value of PMCCNTR_EL0 is UNKNOWN, use reset_unknown for
> its reset handler. Add access handler which emulates writing and reading
> PMCCNTR_EL0 register.
> 
> Signed-off-by: Shannon Zhao <[email-masked]>
> ---
>  arch/arm64/kvm/sys_regs.c | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 2bcf1a0..29883df 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -375,6 +375,23 @@ static bool access_pmxevcntr(struct kvm_vcpu *vcpu,
>  	return true;
>  }
>  
> +static bool access_pmccntr(struct kvm_vcpu *vcpu,
> +			   const struct sys_reg_params *p,
> +			   const struct sys_reg_desc *r)
> +{
> +	unsigned long val;
> +
> +	if (p->is_write) {
> +		val = *vcpu_reg(vcpu, p->Rt);
> +		kvm_pmu_set_counter_value(vcpu, 31, val);

magic number?  do we have some existing define we can use or can we add
one?

> +	} else {
> +		val = kvm_pmu_get_counter_value(vcpu, 31);
> +		*vcpu_reg(vcpu, p->Rt) = val;
> +	}
> +
> +	return true;
> +}
> +
>  /* Silly macro to expand the DBG{BCR,BVR,WVR,WCR}n_EL1 registers in one go */
>  #define DBG_BCR_BVR_WCR_WVR_EL1(n)					\
>  	/* DBGBVRn_EL1 */						\
> @@ -590,7 +607,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	  access_pmceid, reset_pmceid, PMCEID1_EL0, },
>  	/* PMCCNTR_EL0 */
>  	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b000),
> -	  trap_raz_wi },
> +	  access_pmccntr, reset_unknown, PMCCNTR_EL0 },
>  	/* PMXEVTYPER_EL0 */
>  	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b001),
>  	  access_pmxevtyper, reset_unknown, PMXEVTYPER_EL0 },
> -- 
> 2.1.0
>