Merge branch kvm-arm64/pmu-bl into kvmarm-master/next

* kvm-arm64/pmu-bl:
  : .
  : Improve PMU support on heterogeneous systems, courtesy of Alexandru Elisei
  : .
  KVM: arm64: Refuse to run VCPU if the PMU doesn't match the physical CPU
  KVM: arm64: Add KVM_ARM_VCPU_PMU_V3_SET_PMU attribute
  KVM: arm64: Keep a list of probed PMUs
  KVM: arm64: Keep a per-VM pointer to the default PMU
  perf: Fix wrong name in comment for struct perf_cpu_context
  KVM: arm64: Do not change the PMU event filter after a VCPU has run

Signed-off-by: Marc Zyngier <maz@kernel.org>

1 files changed, 33 insertions, 1 deletions

diff --git a/Documentation/virt/kvm/devices/vcpu.rst b/Documentation/virt/kvm/devices/vcpu.rst
index 60a29972d3f1..260db203a1e2 100644
--- a/Documentation/virt/kvm/devices/vcpu.rst
+++ b/Documentation/virt/kvm/devices/vcpu.rst
@@ -70,7 +70,7 @@ irqchip.
 	 -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
+	 -EBUSY   PMUv3 already initialized or a VCPU has already run
 	 -EINVAL  Invalid filter range
 	 =======  ======================================================
 
@@ -104,6 +104,38 @@ 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).
 
+1.4 ATTRIBUTE: KVM_ARM_VCPU_PMU_V3_SET_PMU
+------------------------------------------
+
+:Parameters: in kvm_device_attr.addr the address to an int representing the PMU
+             identifier.
+
+:Returns:
+
+	 =======  ====================================================
+	 -EBUSY   PMUv3 already initialized, a VCPU has already run or
+                  an event filter has already been set
+	 -EFAULT  Error accessing the PMU identifier
+	 -ENXIO   PMU not found
+	 -ENODEV  PMUv3 not supported or GIC not initialized
+	 -ENOMEM  Could not allocate memory
+	 =======  ====================================================
+
+Request that the VCPU uses the specified hardware PMU when creating guest events
+for the purpose of PMU emulation. The PMU identifier can be read from the "type"
+file for the desired PMU instance under /sys/devices (or, equivalent,
+/sys/bus/even_source). This attribute is particularly useful on heterogeneous
+systems where there are at least two CPU PMUs on the system. The PMU that is set
+for one VCPU will be used by all the other VCPUs. It isn't possible to set a PMU
+if a PMU event filter is already present.
+
+Note that KVM will not make any attempts to run the VCPU on the physical CPUs
+associated with the PMU specified by this attribute. This is entirely left to
+userspace. However, attempting to run the VCPU on a physical CPU not supported
+by the PMU will fail and KVM_RUN will return with
+exit_reason = KVM_EXIT_FAIL_ENTRY and populate the fail_entry struct by setting
+hardare_entry_failure_reason field to KVM_EXIT_FAIL_ENTRY_CPU_UNSUPPORTED and
+the cpu field to the processor id.
 
 2. GROUP: KVM_ARM_VCPU_TIMER_CTRL
 =================================