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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH 2/2] KVM: arm64: Document PMU filtering API
Date: Fri, 14 Feb 2020 18:36:15 +0000	[thread overview]
Message-ID: <20200214183615.25498-3-maz@kernel.org> (raw)
In-Reply-To: <20200214183615.25498-1-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.txt | 28 +++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/Documentation/virt/kvm/devices/vcpu.txt b/Documentation/virt/kvm/devices/vcpu.txt
index 6f3bd64a05b0..76902e6bbc05 100644
--- a/Documentation/virt/kvm/devices/vcpu.txt
+++ b/Documentation/virt/kvm/devices/vcpu.txt
@@ -36,6 +36,34 @@ 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 but fit within the 16bit space defined by the ARMv8.1
+PMU architecture.
+
 
 2. GROUP: KVM_ARM_VCPU_TIMER_CTRL
 Architectures: ARM,ARM64
-- 
2.20.1


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  parent reply	other threads:[~2020-02-14 18:36 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14 18:36 [PATCH 0/2] KVM: arm64: Filtering PMU events Marc Zyngier
2020-02-14 18:36 ` [PATCH 1/2] KVM: arm64: Add PMU event filtering infrastructure Marc Zyngier
2020-02-14 22:01   ` Robin Murphy
2020-02-15 10:28     ` Marc Zyngier
2020-02-17 15:33       ` Robin Murphy
2020-02-14 18:36 ` Marc Zyngier [this message]
2020-02-15 13:00 ` [PATCH 0/2] KVM: arm64: Filtering PMU events Marc Zyngier

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