Re: [PATCH v7 12/19] KVM: ARM64: Add access handler for PMOVSSET and PMOVSCLR register

[Marc Zyngier <marc.zyngier@arm.com>]

On 15/12/15 08:49, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@linaro.org>
> 
> Since the reset value of PMOVSSET and PMOVSCLR is UNKNOWN, use
> reset_unknown for its reset handler. Add a handler to emulate writing
> PMOVSSET or PMOVSCLR register.
> 
> When writing non-zero value to PMOVSSET, pend PMU interrupt.

This comment doesn't match the code anymore

> 
> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
> ---
>  arch/arm64/kvm/sys_regs.c | 28 +++++++++++++++++++++++++---
>  include/kvm/arm_pmu.h     |  2 ++
>  virt/kvm/arm/pmu.c        | 20 ++++++++++++++++++++
>  3 files changed, 47 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 594e53f..d1926c4 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -669,6 +669,27 @@ static bool access_pmintenset(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
>  	return true;
>  }
>  
> +static bool access_pmovsset(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> +			    const struct sys_reg_desc *r)
> +{
> +	u64 mask = kvm_pmu_valid_counter_mask(vcpu);
> +
> +	if (p->is_write) {
> +		if (r->CRm & 0x2) {
> +			/* accessing PMOVSSET_EL0 */
> +			kvm_pmu_overflow_set(vcpu, p->regval & mask);
> +		} else {
> +			/* accessing PMOVSCLR_EL0 */
> +			vcpu_sys_reg(vcpu, r->reg) &= mask;
> +			vcpu_sys_reg(vcpu, r->reg) &= ~p->regval;

Same as the previous patch.

> +		}
> +	} else {
> +		p->regval = vcpu_sys_reg(vcpu, r->reg) & mask;
> +	}
> +
> +	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 */						\
> @@ -876,7 +897,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	  access_pmcntenset, NULL, PMCNTENSET_EL0 },
>  	/* PMOVSCLR_EL0 */
>  	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b011),
> -	  trap_raz_wi },
> +	  access_pmovsset, NULL, PMOVSSET_EL0 },
>  	/* PMSWINC_EL0 */
>  	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b100),
>  	  trap_raz_wi },
> @@ -903,7 +924,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	  trap_raz_wi },
>  	/* PMOVSSET_EL0 */
>  	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b011),
> -	  trap_raz_wi },
> +	  access_pmovsset, reset_unknown, PMOVSSET_EL0 },
>  
>  	/* TPIDR_EL0 */
>  	{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b010),
> @@ -1217,7 +1238,7 @@ static const struct sys_reg_desc cp15_regs[] = {
>  	{ Op1( 0), CRn( 9), CRm(12), Op2( 0), access_pmcr },
>  	{ Op1( 0), CRn( 9), CRm(12), Op2( 1), access_pmcntenset },
>  	{ Op1( 0), CRn( 9), CRm(12), Op2( 2), access_pmcntenset },
> -	{ Op1( 0), CRn( 9), CRm(12), Op2( 3), trap_raz_wi },
> +	{ Op1( 0), CRn( 9), CRm(12), Op2( 3), access_pmovsset },
>  	{ Op1( 0), CRn( 9), CRm(12), Op2( 5), access_pmselr },
>  	{ Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmceid },
>  	{ Op1( 0), CRn( 9), CRm(12), Op2( 7), access_pmceid },
> @@ -1227,6 +1248,7 @@ static const struct sys_reg_desc cp15_regs[] = {
>  	{ Op1( 0), CRn( 9), CRm(14), Op2( 0), trap_raz_wi },
>  	{ Op1( 0), CRn( 9), CRm(14), Op2( 1), access_pmintenset },
>  	{ Op1( 0), CRn( 9), CRm(14), Op2( 2), access_pmintenset },
> +	{ Op1( 0), CRn( 9), CRm(14), Op2( 3), access_pmovsset },
>  
>  	{ Op1( 0), CRn(10), CRm( 2), Op2( 0), access_vm_reg, NULL, c10_PRRR },
>  	{ Op1( 0), CRn(10), CRm( 2), Op2( 1), access_vm_reg, NULL, c10_NMRR },
> diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
> index 43c4117..93aea6a 100644
> --- a/include/kvm/arm_pmu.h
> +++ b/include/kvm/arm_pmu.h
> @@ -38,6 +38,7 @@ struct kvm_pmu {
>  u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx);
>  void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val);
>  void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val);
> +void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val);
>  void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
>  				    u64 select_idx);
>  #else
> @@ -50,6 +51,7 @@ u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx)
>  }
>  void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val) {}
>  void kvm_pmu_enable_counter(struct kvm_vcpu *vcpu, u64 val) {}
> +void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val) {}
>  void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
>  				    u64 select_idx) {}
>  #endif
> diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
> index 94bff0e..861471d 100644
> --- a/virt/kvm/arm/pmu.c
> +++ b/virt/kvm/arm/pmu.c
> @@ -130,6 +130,26 @@ void kvm_pmu_disable_counter(struct kvm_vcpu *vcpu, u64 val)
>  }
>  
>  /**
> + * kvm_pmu_overflow_set - set PMU overflow interrupt
> + * @vcpu: The vcpu pointer
> + * @val: the value guest writes to PMOVSSET register
> + */
> +void kvm_pmu_overflow_set(struct kvm_vcpu *vcpu, u64 val)
> +{
> +	u64 reg;
> +
> +	if (val == 0)
> +		return;
> +
> +	vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= val;
> +	reg = vcpu_sys_reg(vcpu, PMOVSSET_EL0)
> +	      & vcpu_sys_reg(vcpu, PMCNTENSET_EL0)
> +	      & vcpu_sys_reg(vcpu, PMINTENSET_EL1);
> +	if (reg != 0)
> +		kvm_vcpu_kick(vcpu);
> +}
> +
> +/**
>   * kvm_pmu_set_counter_event_type - set selected counter to monitor some event
>   * @vcpu: The vcpu pointer
>   * @data: The data guest writes to PMXEVTYPER_EL0
> 

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...