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From: Andrew Murray <andrew.murray@arm.com>
To: Eric Auger <eric.auger@redhat.com>
Cc: maz@kernel.org, linux-kernel@vger.kernel.org,
	kvmarm@lists.cs.columbia.edu, eric.auger.pro@gmail.com
Subject: Re: [RFC 1/3] KVM: arm64: pmu: Don't increment SW_INCR if PMCR.E is unset
Date: Fri, 6 Dec 2019 10:35:05 +0000	[thread overview]
Message-ID: <20191206103505.GM18399@e119886-lin.cambridge.arm.com> (raw)
In-Reply-To: <20191204204426.9628-2-eric.auger@redhat.com>

On Wed, Dec 04, 2019 at 09:44:24PM +0100, Eric Auger wrote:
> The specification says PMSWINC increments PMEVCNTR<n>_EL1 by 1
> if PMEVCNTR<n>_EL0 is enabled and configured to count SW_INCR.
> 
> For PMEVCNTR<n>_EL0 to be enabled, we need both PMCNTENSET to
> be set for the corresponding event counter but we also need
> the PMCR.E bit to be set.
> 
> Fixes: 7a0adc7064b8 ("arm64: KVM: Add access handler for PMSWINC register")
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> ---
>  virt/kvm/arm/pmu.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
> index 8731dfeced8b..c3f8b059881e 100644
> --- a/virt/kvm/arm/pmu.c
> +++ b/virt/kvm/arm/pmu.c
> @@ -486,6 +486,9 @@ void kvm_pmu_software_increment(struct kvm_vcpu *vcpu, u64 val)
>  	if (val == 0)
>  		return;
>  
> +	if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
> +		return;
> +

Reviewed-by: Andrew Murray <andrew.murray@arm.com>


>  	enable = __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
>  	for (i = 0; i < ARMV8_PMU_CYCLE_IDX; i++) {
>  		if (!(val & BIT(i)))
> -- 
> 2.20.1
> 
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  parent reply	other threads:[~2019-12-06 10:35 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-04 20:44 [RFC 0/3] KVM/ARM: Misc PMU fixes Eric Auger
2019-12-04 20:44 ` [RFC 1/3] KVM: arm64: pmu: Don't increment SW_INCR if PMCR.E is unset Eric Auger
2019-12-05  9:54   ` Marc Zyngier
2019-12-06 10:35   ` Andrew Murray [this message]
2019-12-04 20:44 ` [RFC 2/3] KVM: arm64: pmu: Fix chained SW_INCR counters Eric Auger
2019-12-05  9:43   ` Marc Zyngier
2019-12-05 14:06     ` Auger Eric
2019-12-05 14:52       ` Marc Zyngier
2019-12-05 19:01         ` Auger Eric
2019-12-06  9:56           ` Auger Eric
2019-12-06 15:48           ` Andrew Murray
2020-01-19 17:58           ` Marc Zyngier
2020-01-20 13:30             ` Auger Eric
2019-12-06 15:21         ` Andrew Murray
2019-12-06 15:35           ` Marc Zyngier
2019-12-06 16:02             ` Andrew Murray
2019-12-04 20:44 ` [RFC 3/3] KVM: arm64: pmu: Enforce PMEVTYPER evtCount size Eric Auger
2019-12-05  9:02   ` Will Deacon
2019-12-05  9:37     ` Auger Eric

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