From: Will Deacon <will.deacon@arm.com> To: Andrew Murray <andrew.murray@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v10 4/5] arm64: arm_pmu: Add support for exclude_host/exclude_guest attributes Date: Mon, 11 Feb 2019 11:26:19 +0000 [thread overview] Message-ID: <20190211112619.GA32385@fuggles.cambridge.arm.com> (raw) In-Reply-To: <1547482308-29839-5-git-send-email-andrew.murray@arm.com> Hi Andrew, On Mon, Jan 14, 2019 at 04:11:47PM +0000, Andrew Murray wrote: > Add support for the :G and :H attributes in perf by handling the > exclude_host/exclude_guest event attributes. > > We notify KVM of counters that we wish to be enabled or disabled on > guest entry/exit and thus defer from starting or stopping :G events > as per the events exclude_host attribute. > > With both VHE and non-VHE we switch the counters between host/guest > at EL2. We are able to eliminate counters counting host events on > the boundaries of guest entry/exit when using :G by filtering out > EL2 for exclude_host. However when using :H unless exclude_hv is set > on non-VHE then there is a small blackout window at the guest > entry/exit where host events are not captured. > > Signed-off-by: Andrew Murray <andrew.murray@arm.com> > Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > arch/arm64/kernel/perf_event.c | 53 ++++++++++++++++++++++++++++++++++++------ > 1 file changed, 46 insertions(+), 7 deletions(-) [...] > static inline int armv8pmu_enable_intens(int idx) > @@ -824,16 +851,25 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event, > * Therefore we ignore exclude_hv in this configuration, since > * there's no hypervisor to sample anyway. This is consistent > * with other architectures (x86 and Power). > + * > + * To eliminate counting host events on the boundaries of > + * guest entry/exit we ensure EL2 is not included in hyp mode > + * with !exclude_host. > */ > if (is_kernel_in_hyp_mode()) { > - if (!attr->exclude_kernel) > + if (!attr->exclude_kernel && !attr->exclude_host) > config_base |= ARMV8_PMU_INCLUDE_EL2; > } else { > - if (attr->exclude_kernel) > - config_base |= ARMV8_PMU_EXCLUDE_EL1; > if (!attr->exclude_hv) > config_base |= ARMV8_PMU_INCLUDE_EL2; > } > + > + /* > + * Filter out !VHE kernels and guest kernels > + */ > + if (attr->exclude_kernel) > + config_base |= ARMV8_PMU_EXCLUDE_EL1; > + This series needs acks from the KVM folks, but I'd also like Christoffer to confirm that he's happy with the way these checks ended up because I lost track of where we got to on that. Will
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will.deacon@arm.com> To: Andrew Murray <andrew.murray@arm.com> Cc: Mark Rutland <mark.rutland@arm.com>, Suzuki K Poulose <suzuki.poulose@arm.com>, Marc Zyngier <marc.zyngier@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Julien Thierry <julien.thierry@arm.com>, Christoffer Dall <christoffer.dall@arm.com>, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v10 4/5] arm64: arm_pmu: Add support for exclude_host/exclude_guest attributes Date: Mon, 11 Feb 2019 11:26:19 +0000 [thread overview] Message-ID: <20190211112619.GA32385@fuggles.cambridge.arm.com> (raw) In-Reply-To: <1547482308-29839-5-git-send-email-andrew.murray@arm.com> Hi Andrew, On Mon, Jan 14, 2019 at 04:11:47PM +0000, Andrew Murray wrote: > Add support for the :G and :H attributes in perf by handling the > exclude_host/exclude_guest event attributes. > > We notify KVM of counters that we wish to be enabled or disabled on > guest entry/exit and thus defer from starting or stopping :G events > as per the events exclude_host attribute. > > With both VHE and non-VHE we switch the counters between host/guest > at EL2. We are able to eliminate counters counting host events on > the boundaries of guest entry/exit when using :G by filtering out > EL2 for exclude_host. However when using :H unless exclude_hv is set > on non-VHE then there is a small blackout window at the guest > entry/exit where host events are not captured. > > Signed-off-by: Andrew Murray <andrew.murray@arm.com> > Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > arch/arm64/kernel/perf_event.c | 53 ++++++++++++++++++++++++++++++++++++------ > 1 file changed, 46 insertions(+), 7 deletions(-) [...] > static inline int armv8pmu_enable_intens(int idx) > @@ -824,16 +851,25 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event, > * Therefore we ignore exclude_hv in this configuration, since > * there's no hypervisor to sample anyway. This is consistent > * with other architectures (x86 and Power). > + * > + * To eliminate counting host events on the boundaries of > + * guest entry/exit we ensure EL2 is not included in hyp mode > + * with !exclude_host. > */ > if (is_kernel_in_hyp_mode()) { > - if (!attr->exclude_kernel) > + if (!attr->exclude_kernel && !attr->exclude_host) > config_base |= ARMV8_PMU_INCLUDE_EL2; > } else { > - if (attr->exclude_kernel) > - config_base |= ARMV8_PMU_EXCLUDE_EL1; > if (!attr->exclude_hv) > config_base |= ARMV8_PMU_INCLUDE_EL2; > } > + > + /* > + * Filter out !VHE kernels and guest kernels > + */ > + if (attr->exclude_kernel) > + config_base |= ARMV8_PMU_EXCLUDE_EL1; > + This series needs acks from the KVM folks, but I'd also like Christoffer to confirm that he's happy with the way these checks ended up because I lost track of where we got to on that. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-02-11 11:26 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-14 16:11 [PATCH v10 0/5] arm64: Support perf event modifiers :G and :H Andrew Murray 2019-01-14 16:11 ` Andrew Murray 2019-01-14 16:11 ` [PATCH v10 1/5] arm64: arm_pmu: remove unnecessary isb instruction Andrew Murray 2019-01-14 16:11 ` Andrew Murray 2019-01-14 16:11 ` [PATCH v10 2/5] arm64: KVM: encapsulate kvm_cpu_context in kvm_host_data Andrew Murray 2019-01-14 16:11 ` Andrew Murray 2019-01-14 16:11 ` [PATCH v10 3/5] arm64: KVM: add accessors to track guest/host only counters Andrew Murray 2019-01-14 16:11 ` Andrew Murray 2019-01-14 16:11 ` [PATCH v10 4/5] arm64: arm_pmu: Add support for exclude_host/exclude_guest attributes Andrew Murray 2019-01-14 16:11 ` Andrew Murray 2019-02-11 11:26 ` Will Deacon [this message] 2019-02-11 11:26 ` Will Deacon 2019-02-18 21:53 ` Christoffer Dall 2019-02-18 21:53 ` Christoffer Dall 2019-02-20 16:15 ` Andrew Murray 2019-02-20 16:15 ` Andrew Murray 2019-02-26 12:44 ` Christoffer Dall 2019-02-26 12:44 ` Christoffer Dall 2019-03-04 11:14 ` Andrew Murray 2019-03-04 11:14 ` Andrew Murray 2019-03-05 11:45 ` Andrew Murray 2019-03-05 11:45 ` Andrew Murray 2019-03-06 8:42 ` Christoffer Dall 2019-03-06 8:42 ` Christoffer Dall 2019-01-14 16:11 ` [PATCH v10 5/5] arm64: KVM: Enable support for :G/:H perf event modifiers Andrew Murray 2019-01-14 16:11 ` Andrew Murray 2019-02-18 22:00 ` Christoffer Dall 2019-02-18 22:00 ` Christoffer Dall 2019-03-04 9:40 ` Andrew Murray 2019-03-04 9:40 ` Andrew Murray
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