forked from Minki/linux
c07a0191ef
Add infrastructure to handle distributor and cpu interface register
accesses through the KVM_{GET/SET}_DEVICE_ATTR interface by adding the
KVM_DEV_ARM_VGIC_GRP_DIST_REGS and KVM_DEV_ARM_VGIC_GRP_CPU_REGS groups
and defining the semantics of the attr field to be the MMIO offset as
specified in the GICv2 specs.
Missing register accesses or other changes in individual register access
functions to support save/restore of the VGIC state is added in
subsequent patches.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
74 lines
3.0 KiB
Plaintext
74 lines
3.0 KiB
Plaintext
ARM Virtual Generic Interrupt Controller (VGIC)
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===============================================
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Device types supported:
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KVM_DEV_TYPE_ARM_VGIC_V2 ARM Generic Interrupt Controller v2.0
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Only one VGIC instance may be instantiated through either this API or the
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legacy KVM_CREATE_IRQCHIP api. The created VGIC will act as the VM interrupt
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controller, requiring emulated user-space devices to inject interrupts to the
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VGIC instead of directly to CPUs.
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Groups:
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KVM_DEV_ARM_VGIC_GRP_ADDR
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Attributes:
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KVM_VGIC_V2_ADDR_TYPE_DIST (rw, 64-bit)
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Base address in the guest physical address space of the GIC distributor
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register mappings.
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KVM_VGIC_V2_ADDR_TYPE_CPU (rw, 64-bit)
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Base address in the guest physical address space of the GIC virtual cpu
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interface register mappings.
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KVM_DEV_ARM_VGIC_GRP_DIST_REGS
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Attributes:
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The attr field of kvm_device_attr encodes two values:
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bits: | 63 .... 40 | 39 .. 32 | 31 .... 0 |
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values: | reserved | cpu id | offset |
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All distributor regs are (rw, 32-bit)
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The offset is relative to the "Distributor base address" as defined in the
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GICv2 specs. Getting or setting such a register has the same effect as
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reading or writing the register on the actual hardware from the cpu
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specified with cpu id field. Note that most distributor fields are not
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banked, but return the same value regardless of the cpu id used to access
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the register.
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Limitations:
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- Priorities are not implemented, and registers are RAZ/WI
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Errors:
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-ENODEV: Getting or setting this register is not yet supported
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-EBUSY: One or more VCPUs are running
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KVM_DEV_ARM_VGIC_GRP_CPU_REGS
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Attributes:
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The attr field of kvm_device_attr encodes two values:
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bits: | 63 .... 40 | 39 .. 32 | 31 .... 0 |
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values: | reserved | cpu id | offset |
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All CPU interface regs are (rw, 32-bit)
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The offset specifies the offset from the "CPU interface base address" as
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defined in the GICv2 specs. Getting or setting such a register has the
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same effect as reading or writing the register on the actual hardware.
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The Active Priorities Registers APRn are implementation defined, so we set a
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fixed format for our implementation that fits with the model of a "GICv2
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implementation without the security extensions" which we present to the
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guest. This interface always exposes four register APR[0-3] describing the
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maximum possible 128 preemption levels. The semantics of the register
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indicate if any interrupts in a given preemption level are in the active
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state by setting the corresponding bit.
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Thus, preemption level X has one or more active interrupts if and only if:
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APRn[X mod 32] == 0b1, where n = X / 32
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Bits for undefined preemption levels are RAZ/WI.
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Limitations:
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- Priorities are not implemented, and registers are RAZ/WI
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Errors:
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-ENODEV: Getting or setting this register is not yet supported
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-EBUSY: One or more VCPUs are running
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