[2/2] KVM: arm64: Document PMU filtering API
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Message ID 20200214183615.25498-3-maz@kernel.org
State New
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Series
  • KVM: arm64: Filtering PMU events
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Commit Message

Marc Zyngier Feb. 14, 2020, 6:36 p.m. UTC
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(+)

Patch
diff mbox series

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