Re: [PATCH v2 1/9] arm64: KVM: PMU: Refactor pmu_*_el0_disabled

Christoffer Dall
2017-03-28T12:44:28Z

On Mon, Mar 27, 2017 at 05:03:37PM +0100, Marc Zyngier wrote:
> There is a lot of duplication in the pmu_*_el0_disabled helpers,
> and as we're going to modify them shortly, let's move all the
> common stuff in a single function.
>
> No functionnal change.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> arch/arm64/kvm/sys_regs.c | 25 +++++++++++--------------
> 1 file changed, 11 insertions(+), 14 deletions(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 0e26f8c2b56f..7e1d673304d5 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -460,35 +460,32 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> vcpu_sys_reg(vcpu, PMCR_EL0) = val;
> }
>
> -static bool pmu_access_el0_disabled(struct kvm_vcpu *vcpu)
> +static bool check_disabled(struct kvm_vcpu *vcpu, u64 flags)
> {
> u64 reg = vcpu_sys_reg(vcpu, PMUSERENR_EL0);
> + bool cond = (reg & flags) || vcpu_mode_priv(vcpu);

nit: I would call this variable 'enabled' and then return !enabled to
make it clear what's going on.

(If you agree, I can fix this up when applying along with the typo and
rename pointed out by Suzuki).

>
> - return !((reg & ARMV8_PMU_USERENR_EN) || vcpu_mode_priv(vcpu));
> + return !cond;
> }
>
> -static bool pmu_write_swinc_el0_disabled(struct kvm_vcpu *vcpu)
> +static bool pmu_access_el0_disabled(struct kvm_vcpu *vcpu)
> {
> - u64 reg = vcpu_sys_reg(vcpu, PMUSERENR_EL0);
> + return check_disabled(vcpu, ARMV8_PMU_USERENR_EN);
> +}
>
> - return !((reg & (ARMV8_PMU_USERENR_SW | ARMV8_PMU_USERENR_EN))
> - || vcpu_mode_priv(vcpu));
> +static bool pmu_write_swinc_el0_disabled(struct kvm_vcpu *vcpu)
> +{
> + return check_disabled(vcpu, ARMV8_PMU_USERENR_SW | ARMV8_PMU_USERENR_EN);
> }
>
> static bool pmu_access_cycle_counter_el0_disabled(struct kvm_vcpu *vcpu)
> {
> - u64 reg = vcpu_sys_reg(vcpu, PMUSERENR_EL0);
> -
> - return !((reg & (ARMV8_PMU_USERENR_CR | ARMV8_PMU_USERENR_EN))
> - || vcpu_mode_priv(vcpu));
> + return check_disabled(vcpu, ARMV8_PMU_USERENR_CR | ARMV8_PMU_USERENR_EN);
> }
>
> static bool pmu_access_event_counter_el0_disabled(struct kvm_vcpu *vcpu)
> {
> - u64 reg = vcpu_sys_reg(vcpu, PMUSERENR_EL0);
> -
> - return !((reg & (ARMV8_PMU_USERENR_ER | ARMV8_PMU_USERENR_EN))
> - || vcpu_mode_priv(vcpu));
> + return check_disabled(vcpu, ARMV8_PMU_USERENR_ER | ARMV8_PMU_USERENR_EN);
> }
>
> static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> --
> 2.11.0
>

Otherwise:

Reviewed-by: Christoffer Dall <cdall@linaro.org>