From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Eric Auger <eric.auger@redhat.com>,
James Morse <james.morse@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: [PATCH v2 2/2] KVM: arm64: Document PMU filtering API
Date: Mon, 9 Mar 2020 12:48:37 +0000 [thread overview]
Message-ID: <20200309124837.19908-3-maz@kernel.org> (raw)
In-Reply-To: <20200309124837.19908-1-maz@kernel.org>
Add a small blurb describing how the event filtering API gets used.
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
Documentation/virt/kvm/devices/vcpu.rst | 40 +++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/Documentation/virt/kvm/devices/vcpu.rst b/Documentation/virt/kvm/devices/vcpu.rst
index 9963e680770a..7262c0469856 100644
--- a/Documentation/virt/kvm/devices/vcpu.rst
+++ b/Documentation/virt/kvm/devices/vcpu.rst
@@ -55,6 +55,46 @@ Request the initialization of the PMUv3. If using the PMUv3 with an in-kernel
virtual GIC implementation, this must be done after initializing the in-kernel
irqchip.
+1.3 ATTRIBUTE: KVM_ARM_VCPU_PMU_V3_FILTER
+---------------------------------------
+
+:Parameters: in kvm_device_attr.addr the address for a PMU event filter is a
+ pointer to a struct kvm_pmu_event_filter
+
+:Returns:
+
+ ======= ======================================================
+ -ENODEV: PMUv3 not supported or GIC not initialized
+ -ENXIO: PMUv3 not properly configured or in-kernel irqchip not
+ configured as required prior to calling this attribute
+ -EBUSY: PMUv3 already initialized
+ ======= ======================================================
+
+Request the installation of a PMU event filter describe as follows:
+
+struct kvm_pmu_event_filter {
+ __u16 base_event;
+ __u16 nevents;
+
+#define KVM_PMU_EVENT_ALLOW 0
+#define KVM_PMU_EVENT_DENY 1
+
+ __u8 action;
+ __u8 pad[3];
+};
+
+A filter range is defined as the range [@base_event, @base_event + @nevents[,
+together with an @action (KVM_PMU_EVENT_ALLOW or KVM_PMU_EVENT_DENY). The
+first registered range defines the global policy (global ALLOW if the first
+@action is DENY, global DENY if the first @action is ALLOW). Multiple ranges
+can be programmed, and must fit within the 16bit space defined by the ARMv8.1
+PMU architecture.
+
+Restrictions: Event 0 (SW_INCR) is never filtered, as it doesn't count a
+hardware event. Filtering event 0x1E (CHAIN) has no effect either, as it
+isn't strictly speaking an event. Filtering the cycle counter is possible
+using event 0x11 (CPU_CYCLES).
+
2. GROUP: KVM_ARM_VCPU_TIMER_CTRL
=================================
--
2.20.1
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next prev parent reply other threads:[~2020-03-09 12:49 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 12:48 [PATCH v2 0/2] KVM: arm64: Filtering PMU events Marc Zyngier
2020-03-09 12:48 ` [PATCH v2 1/2] KVM: arm64: Add PMU event filtering infrastructure Marc Zyngier
2020-03-09 18:05 ` Auger Eric
2020-03-10 11:03 ` Marc Zyngier
2020-03-10 17:40 ` Auger Eric
2020-03-10 18:00 ` Marc Zyngier
2020-03-10 18:26 ` Auger Eric
2020-08-18 23:24 ` Alexander Graf
2020-08-20 7:37 ` Marc Zyngier
2020-09-02 12:23 ` Alexander Graf
2020-03-09 12:48 ` Marc Zyngier [this message]
2020-03-09 18:17 ` [PATCH v2 2/2] KVM: arm64: Document PMU filtering API Auger Eric
2020-03-10 11:54 ` Marc Zyngier
2020-03-10 17:30 ` Auger Eric
2020-03-10 18:07 ` Marc Zyngier
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