Generic vcpu interface

The virtual cpu “device” also accepts the ioctls KVM_SET_DEVICE_ATTR, KVM_GET_DEVICE_ATTR, and KVM_HAS_DEVICE_ATTR. The interface uses the same struct kvm_device_attr as other devices, but targets VCPU-wide settings and controls.

The groups and attributes per virtual cpu, if any, are architecture specific.

1. GROUP: KVM_ARM_VCPU_PMU_V3_CTRL

Architectures:ARM64

1.1. ATTRIBUTE: KVM_ARM_VCPU_PMU_V3_IRQ

Parameters:in kvm_device_attr.addr the address for PMU overflow interrupt is a pointer to an int

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 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 type must be same for each vcpu. As a PPI, the interrupt number is the same for 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 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 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.

2. GROUP: KVM_ARM_VCPU_TIMER_CTRL

Architectures:ARM, ARM64

2.1. ATTRIBUTES: KVM_ARM_VCPU_TIMER_IRQ_VTIMER, KVM_ARM_VCPU_TIMER_IRQ_PTIMER

Parameters:in kvm_device_attr.addr the address for the timer interrupt is a pointer to an int

Returns:

-EINVAL Invalid timer interrupt number
-EBUSY One or more VCPUs has already run

A value describing the architected timer interrupt number when connected to an in-kernel virtual GIC. These must be a PPI (16 <= intid < 32). Setting the attribute overrides the default values (see below).

KVM_ARM_VCPU_TIMER_IRQ_VTIMER The EL1 virtual timer intid (default: 27)
KVM_ARM_VCPU_TIMER_IRQ_PTIMER The EL1 physical timer intid (default: 30)

Setting the same PPI for different timers will prevent the VCPUs from running. Setting the interrupt number on a VCPU configures all VCPUs created at that time to use the number provided for a given timer, overwriting any previously configured values on other VCPUs. Userspace should configure the interrupt numbers on at least one VCPU after creating all VCPUs and before running any VCPUs.

3. GROUP: KVM_ARM_VCPU_PVTIME_CTRL

Architectures:ARM64

3.1 ATTRIBUTE: KVM_ARM_VCPU_PVTIME_IPA

Parameters:64-bit base address

Returns:

-ENXIO Stolen time not implemented
-EEXIST Base address already set for this VCPU
-EINVAL Base address not 64 byte aligned

Specifies the base address of the stolen time structure for this VCPU. The base address must be 64 byte aligned and exist within a valid guest memory region. See Documentation/virt/kvm/arm/pvtime.txt for more information including the layout of the stolen time structure.