Since we got support for devices in userspace which allows reporting the
PMU overflow output status to userspace, we should actually allow
creating the PMU on systems without an in-kernel irqchip, which in turn
requires us to slightly clarify error codes for the ABI and move things
around for the initialization phase.
Signed-off-by: Christoffer Dall <cdall@xxxxxxxxxx>
---
Documentation/virtual/kvm/devices/vcpu.txt | 16 +++++++++-------
virt/kvm/arm/pmu.c | 27 +++++++++++++++++----------
2 files changed, 26 insertions(+), 17 deletions(-)
diff --git a/Documentation/virtual/kvm/devices/vcpu.txt b/Documentation/virtual/kvm/devices/vcpu.txt
index 02f5068..352af6e 100644
--- a/Documentation/virtual/kvm/devices/vcpu.txt
+++ b/Documentation/virtual/kvm/devices/vcpu.txt
@@ -16,7 +16,9 @@ Parameters: in kvm_device_attr.addr the address for PMU overflow interrupt is a
Returns: -EBUSY: The PMU overflow interrupt is already set
-ENXIO: The overflow interrupt not set when attempting to get it
-ENODEV: PMUv3 not supported
- -EINVAL: Invalid PMU overflow interrupt number supplied
+ -EINVAL: Invalid PMU overflow interrupt number supplied or
+ trying to set the IRQ number without using an in-kernel
+ irqchip.
A value describing the PMUv3 (Performance Monitor Unit v3) overflow interrupt
number for this vcpu. This interrupt could be a PPI or SPI, but the interrupt
@@ -25,11 +27,11 @@ all vcpus, while as an SPI it must be a separate number per vcpu.
1.2 ATTRIBUTE: KVM_ARM_VCPU_PMU_V3_INIT
Parameters: no additional parameter in kvm_device_attr.addr
-Returns: -ENODEV: PMUv3 not supported
- -ENXIO: PMUv3 not properly configured as required prior to calling this
- attribute
+Returns: -ENODEV: PMUv3 not supported or GIC not initialized
+ -ENXIO: PMUv3 not properly configured or in-kernel irqchip not
+ conigured as required prior to calling this attribute
-EBUSY: PMUv3 already initialized
-Request the initialization of the PMUv3. This must be done after creating the
-in-kernel irqchip. Creating a PMU with a userspace irqchip is currently not
-supported.
+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.
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 4b43e7f..f046b08 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -456,21 +456,25 @@ static int kvm_arm_pmu_v3_init(struct kvm_vcpu *vcpu)
if (!kvm_arm_support_pmu_v3())
return -ENODEV;
- /*
- * We currently require an in-kernel VGIC to use the PMU emulation,
- * because we do not support forwarding PMU overflow interrupts to
- * userspace yet.
- */
- if (!irqchip_in_kernel(vcpu->kvm) || !vgic_initialized(vcpu->kvm))
- return -ENODEV;
-
- if (!test_bit(KVM_ARM_VCPU_PMU_V3, vcpu->arch.features) ||
- !kvm_arm_pmu_irq_initialized(vcpu))
+ if (!test_bit(KVM_ARM_VCPU_PMU_V3, vcpu->arch.features))
return -ENXIO;
if (kvm_arm_pmu_v3_ready(vcpu))
return -EBUSY;
+ if (irqchip_in_kernel(vcpu->kvm)) {
+ /*
+ * If using the PMU with an in-kernel virtual GIC
+ * implementation, we require the GIC to be already
+ * initialized when initializing the PMU.
+ */
+ if (!vgic_initialized(vcpu->kvm))
+ return -ENODEV;
+
+ if (!kvm_arm_pmu_irq_initialized(vcpu))
+ return -ENXIO;
+ }
+
kvm_pmu_vcpu_reset(vcpu);
vcpu->arch.pmu.ready = true;
@@ -512,6 +516,9 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
int __user *uaddr = (int __user *)(long)attr->addr;
int irq;
+ if (!irqchip_in_kernel(vcpu->kvm))
+ return -EINVAL;
+
if (!test_bit(KVM_ARM_VCPU_PMU_V3, vcpu->arch.features))
return -ENODEV;
--
2.9.0
