From: Alexandru Elisei <alexandru.elisei@arm.com>
To: Marc Zyngier <maz@kernel.org>,
linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
kvmarm@lists.cs.columbia.edu
Cc: kernel-team@android.com, Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH 2/3] KVM: arm64: Drop unnecessary masking of PMU registers
Date: Wed, 14 Jul 2021 17:12:03 +0100 [thread overview]
Message-ID: <e67684f9-e5df-072c-b6ac-f5adecfeb260@arm.com> (raw)
In-Reply-To: <20210713135900.1473057-3-maz@kernel.org>
Hi Marc,
On 7/13/21 2:58 PM, Marc Zyngier wrote:
> We always sanitise our PMU sysreg on the write side, so there
> is no need to do it on the read side as well.
>
> Drop the unnecessary masking.
Checked for all the remaining uses of kvm_pmu_valid_counter_mask in sys_regs.c and
in pmu-emul.c, and nothing stands out:
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Thanks,
Alex
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> arch/arm64/kvm/pmu-emul.c | 3 +--
> arch/arm64/kvm/sys_regs.c | 6 +++---
> 2 files changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
> index f33825c995cb..fae4e95b586c 100644
> --- a/arch/arm64/kvm/pmu-emul.c
> +++ b/arch/arm64/kvm/pmu-emul.c
> @@ -373,7 +373,6 @@ static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
> reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
> reg &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
> reg &= __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
> - reg &= kvm_pmu_valid_counter_mask(vcpu);
> }
>
> return reg;
> @@ -569,7 +568,7 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
>
> if (val & ARMV8_PMU_PMCR_E) {
> kvm_pmu_enable_counter_mask(vcpu,
> - __vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & mask);
> + __vcpu_sys_reg(vcpu, PMCNTENSET_EL0));
> } else {
> kvm_pmu_disable_counter_mask(vcpu, mask);
> }
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 95ccb8f45409..7ead93a8d67f 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -883,7 +883,7 @@ static bool access_pmcnten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> kvm_pmu_disable_counter_mask(vcpu, val);
> }
> } else {
> - p->regval = __vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & mask;
> + p->regval = __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
> }
>
> return true;
> @@ -907,7 +907,7 @@ static bool access_pminten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> /* accessing PMINTENCLR_EL1 */
> __vcpu_sys_reg(vcpu, PMINTENSET_EL1) &= ~val;
> } else {
> - p->regval = __vcpu_sys_reg(vcpu, PMINTENSET_EL1) & mask;
> + p->regval = __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
> }
>
> return true;
> @@ -929,7 +929,7 @@ static bool access_pmovs(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> /* accessing PMOVSCLR_EL0 */
> __vcpu_sys_reg(vcpu, PMOVSSET_EL0) &= ~(p->regval & mask);
> } else {
> - p->regval = __vcpu_sys_reg(vcpu, PMOVSSET_EL0) & mask;
> + p->regval = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
> }
>
> return true;
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next prev parent reply other threads:[~2021-07-14 16:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-13 13:58 [PATCH 0/3] kvm-arm64: Fix PMU reset values (and more) Marc Zyngier
2021-07-13 13:58 ` [PATCH 1/3] KVM: arm64: Narrow PMU sysreg reset values to architectural requirements Marc Zyngier
2021-07-13 14:39 ` Russell King (Oracle)
2021-07-13 15:59 ` Marc Zyngier
2021-07-13 16:15 ` Russell King (Oracle)
2021-07-14 15:48 ` Alexandru Elisei
2021-07-15 11:11 ` Marc Zyngier
2021-07-15 11:51 ` Robin Murphy
2021-07-15 12:25 ` Marc Zyngier
2021-07-13 13:58 ` [PATCH 2/3] KVM: arm64: Drop unnecessary masking of PMU registers Marc Zyngier
2021-07-14 16:12 ` Alexandru Elisei [this message]
2021-07-13 13:59 ` [PATCH 3/3] KVM: arm64: Disabling disabled PMU counters wastes a lot of time Marc Zyngier
2021-07-14 16:18 ` Alexandru Elisei
2021-07-15 8:34 ` [PATCH 0/3] kvm-arm64: Fix PMU reset values (and more) Alexandre Chartre
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