Subject: [PATCH 16/18] KVM: ARM64: Add access handlers for PMEVCNTRn_EL0 and PMEVTYPERn_EL0 register

From: [email-masked] (Christoffer Dall)
Date: Fri, 17 Jul 2015 17:19:00 +0200

On Mon, Jul 06, 2015 at 10:17:46AM +0800, shannon.zhao at linaro.org wrote:
> From: Shannon Zhao <[email-masked]>
> 
> Add access handler which emulates writing and reading PMEVCNTRn_EL0 and
> PMEVTYPERn_EL0.
> 
> Signed-off-by: Shannon Zhao <[email-masked]>
> ---
>  arch/arm64/kvm/sys_regs.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 106 insertions(+)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 70afcba..5663d83 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -548,6 +548,30 @@ static bool access_pmswinc(struct kvm_vcpu *vcpu,
>  	return true;
>  }
>  
> +/* PMU reg accessor. */
> +static bool access_pmu_reg(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);
> +		if (!p->is_aarch32)
> +			vcpu_sys_reg(vcpu, r->reg) = val;
> +		else
> +			vcpu_cp15(vcpu, r->reg) = val & 0xffffffffUL;
> +	} else {
> +		if (!p->is_aarch32)
> +			val = vcpu_sys_reg(vcpu, r->reg);
> +		else
> +			val = vcpu_cp15(vcpu, r->reg);
> +		*vcpu_reg(vcpu, p->Rt) = val;
> +	}

shouldn't these functions act completely analogously to access_pmxevcntr
(introduced in patch 09/18), only instead of using the valur of
PMSELR_EL0 for the index, this should be some offset calculation or
r->reg?

I think you also need a 32-bit mapping with the right offset for the
p->is_aarch32 check to make sense here (I may have forgotten this in a
few patches, please check all of them for this).

> +
> +	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 */						\
> @@ -563,6 +587,20 @@ static bool access_pmswinc(struct kvm_vcpu *vcpu,
>  	{ Op0(0b10), Op1(0b000), CRn(0b0000), CRm((n)), Op2(0b111),	\
>  	  trap_debug_regs, reset_val, (DBGWCR0_EL1 + (n)), 0 }
>  
> +/* Macro to expand the PMEVCNTRn_EL0 register */
> +#define PMU_PMEVCNTR_EL0(n)						\
> +	/* PMEVCNTRn_EL0 */						\
> +	{ Op0(0b11), Op1(0b011), CRn(0b1110),				\
> +	  CRm((0b1000 | (((n) >> 3) & 0x3))), Op2(((n) & 0x7)),		\
> +	  access_pmu_reg, reset_val, (PMEVCNTR0_EL0 + (n)*2), 0 }
> +
> +/* Macro to expand the PMEVTYPERn_EL0 register */
> +#define PMU_PMEVTYPER_EL0(n)						\
> +	/* PMEVTYPERn_EL0 */						\
> +	{ Op0(0b11), Op1(0b011), CRn(0b1110),				\
> +	  CRm((0b1100 | (((n) >> 3) & 0x3))), Op2(((n) & 0x7)),		\
> +	  access_pmu_reg, reset_val, (PMEVTYPER0_EL0 + (n)*2), 0 }
> +
>  /*
>   * Architected system registers.
>   * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
> @@ -784,6 +822,74 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b011),
>  	  NULL, reset_unknown, TPIDRRO_EL0 },
>  
> +	/* PMEVCNTRn_EL0 */
> +	PMU_PMEVCNTR_EL0(0),
> +	PMU_PMEVCNTR_EL0(1),
> +	PMU_PMEVCNTR_EL0(2),
> +	PMU_PMEVCNTR_EL0(3),
> +	PMU_PMEVCNTR_EL0(4),
> +	PMU_PMEVCNTR_EL0(5),
> +	PMU_PMEVCNTR_EL0(6),
> +	PMU_PMEVCNTR_EL0(7),
> +	PMU_PMEVCNTR_EL0(8),
> +	PMU_PMEVCNTR_EL0(9),
> +	PMU_PMEVCNTR_EL0(10),
> +	PMU_PMEVCNTR_EL0(11),
> +	PMU_PMEVCNTR_EL0(12),
> +	PMU_PMEVCNTR_EL0(13),
> +	PMU_PMEVCNTR_EL0(14),
> +	PMU_PMEVCNTR_EL0(15),
> +	PMU_PMEVCNTR_EL0(16),
> +	PMU_PMEVCNTR_EL0(17),
> +	PMU_PMEVCNTR_EL0(18),
> +	PMU_PMEVCNTR_EL0(19),
> +	PMU_PMEVCNTR_EL0(20),
> +	PMU_PMEVCNTR_EL0(21),
> +	PMU_PMEVCNTR_EL0(22),
> +	PMU_PMEVCNTR_EL0(23),
> +	PMU_PMEVCNTR_EL0(24),
> +	PMU_PMEVCNTR_EL0(25),
> +	PMU_PMEVCNTR_EL0(26),
> +	PMU_PMEVCNTR_EL0(27),
> +	PMU_PMEVCNTR_EL0(28),
> +	PMU_PMEVCNTR_EL0(29),
> +	PMU_PMEVCNTR_EL0(30),
> +	/* PMEVTYPERn_EL0 */
> +	PMU_PMEVTYPER_EL0(0),
> +	PMU_PMEVTYPER_EL0(1),
> +	PMU_PMEVTYPER_EL0(2),
> +	PMU_PMEVTYPER_EL0(3),
> +	PMU_PMEVTYPER_EL0(4),
> +	PMU_PMEVTYPER_EL0(5),
> +	PMU_PMEVTYPER_EL0(6),
> +	PMU_PMEVTYPER_EL0(7),
> +	PMU_PMEVTYPER_EL0(8),
> +	PMU_PMEVTYPER_EL0(9),
> +	PMU_PMEVTYPER_EL0(10),
> +	PMU_PMEVTYPER_EL0(11),
> +	PMU_PMEVTYPER_EL0(12),
> +	PMU_PMEVTYPER_EL0(13),
> +	PMU_PMEVTYPER_EL0(14),
> +	PMU_PMEVTYPER_EL0(15),
> +	PMU_PMEVTYPER_EL0(16),
> +	PMU_PMEVTYPER_EL0(17),
> +	PMU_PMEVTYPER_EL0(18),
> +	PMU_PMEVTYPER_EL0(19),
> +	PMU_PMEVTYPER_EL0(20),
> +	PMU_PMEVTYPER_EL0(21),
> +	PMU_PMEVTYPER_EL0(22),
> +	PMU_PMEVTYPER_EL0(23),
> +	PMU_PMEVTYPER_EL0(24),
> +	PMU_PMEVTYPER_EL0(25),
> +	PMU_PMEVTYPER_EL0(26),
> +	PMU_PMEVTYPER_EL0(27),
> +	PMU_PMEVTYPER_EL0(28),
> +	PMU_PMEVTYPER_EL0(29),
> +	PMU_PMEVTYPER_EL0(30),
> +	/* PMCCFILTR_EL0 */
> +	{ Op0(0b11), Op1(0b011), CRn(0b1110), CRm(0b1111), Op2(0b111),
> +	  access_pmu_reg, reset_val, PMCCFILTR_EL0, 0 },
> +

why is PMCCFULTR just accessing state on the VCPU, shouldn't this have
the same behavior as accesses to PMXEVTYPER_EL0, just for the cycle
counter event?

>  	/* DACR32_EL2 */
>  	{ Op0(0b11), Op1(0b100), CRn(0b0011), CRm(0b0000), Op2(0b000),
>  	  NULL, reset_unknown, DACR32_EL2 },
> -- 
> 2.1.0
> 

Thanks,
-Christoffer