292 lines
12 KiB
ReStructuredText
292 lines
12 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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==============================================================
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ARM Virtual Generic Interrupt Controller v3 and later (VGICv3)
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==============================================================
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Device types supported:
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- KVM_DEV_TYPE_ARM_VGIC_V3 ARM Generic Interrupt Controller v3.0
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Only one VGIC instance may be instantiated through this API. The created VGIC
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will act as the VM interrupt controller, requiring emulated user-space devices
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to inject interrupts to the VGIC instead of directly to CPUs. It is not
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possible to create both a GICv3 and GICv2 on the same VM.
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Creating a guest GICv3 device requires a host GICv3 as well.
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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_V3_ADDR_TYPE_DIST (rw, 64-bit)
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Base address in the guest physical address space of the GICv3 distributor
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register mappings. Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
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This address needs to be 64K aligned and the region covers 64 KByte.
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KVM_VGIC_V3_ADDR_TYPE_REDIST (rw, 64-bit)
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Base address in the guest physical address space of the GICv3
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redistributor register mappings. There are two 64K pages for each
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VCPU and all of the redistributor pages are contiguous.
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Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
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This address needs to be 64K aligned.
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KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION (rw, 64-bit)
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The attribute data pointed to by kvm_device_attr.addr is a __u64 value::
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bits: | 63 .... 52 | 51 .... 16 | 15 - 12 |11 - 0
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values: | count | base | flags | index
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- index encodes the unique redistributor region index
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- flags: reserved for future use, currently 0
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- base field encodes bits [51:16] of the guest physical base address
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of the first redistributor in the region.
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- count encodes the number of redistributors in the region. Must be
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greater than 0.
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There are two 64K pages for each redistributor in the region and
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redistributors are laid out contiguously within the region. Regions
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are filled with redistributors in the index order. The sum of all
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region count fields must be greater than or equal to the number of
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VCPUs. Redistributor regions must be registered in the incremental
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index order, starting from index 0.
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The characteristics of a specific redistributor region can be read
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by presetting the index field in the attr data.
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Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
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It is invalid to mix calls with KVM_VGIC_V3_ADDR_TYPE_REDIST and
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KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION attributes.
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Errors:
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======= =============================================================
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-E2BIG Address outside of addressable IPA range
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-EINVAL Incorrectly aligned address, bad redistributor region
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count/index, mixed redistributor region attribute usage
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-EEXIST Address already configured
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-ENOENT Attempt to read the characteristics of a non existing
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redistributor region
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-ENXIO The group or attribute is unknown/unsupported for this device
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or hardware support is missing.
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-EFAULT Invalid user pointer for attr->addr.
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======= =============================================================
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KVM_DEV_ARM_VGIC_GRP_DIST_REGS, KVM_DEV_ARM_VGIC_GRP_REDIST_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 .... 32 | 31 .... 0 |
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values: | mpidr | offset |
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All distributor regs are (rw, 32-bit) and kvm_device_attr.addr points to a
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__u32 value. 64-bit registers must be accessed by separately accessing the
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lower and higher word.
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Writes to read-only registers are ignored by the kernel.
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KVM_DEV_ARM_VGIC_GRP_DIST_REGS accesses the main distributor registers.
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KVM_DEV_ARM_VGIC_GRP_REDIST_REGS accesses the redistributor of the CPU
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specified by the mpidr.
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The offset is relative to the "[Re]Distributor base address" as defined
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in the GICv3/4 specs. Getting or setting such a register has the same
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effect as reading or writing the register on real hardware, except for the
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following registers: GICD_STATUSR, GICR_STATUSR, GICD_ISPENDR,
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GICR_ISPENDR0, GICD_ICPENDR, and GICR_ICPENDR0. These registers behave
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differently when accessed via this interface compared to their
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architecturally defined behavior to allow software a full view of the
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VGIC's internal state.
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The mpidr field is used to specify which
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redistributor is accessed. The mpidr is ignored for the distributor.
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The mpidr encoding is based on the affinity information in the
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architecture defined MPIDR, and the field is encoded as follows::
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| 63 .... 56 | 55 .... 48 | 47 .... 40 | 39 .... 32 |
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| Aff3 | Aff2 | Aff1 | Aff0 |
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Note that distributor fields are not banked, but return the same value
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regardless of the mpidr used to access the register.
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GICD_IIDR.Revision is updated when the KVM implementation is changed in a
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way directly observable by the guest or userspace. Userspace should read
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GICD_IIDR from KVM and write back the read value to confirm its expected
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behavior is aligned with the KVM implementation. Userspace should set
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GICD_IIDR before setting any other registers to ensure the expected
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behavior.
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The GICD_STATUSR and GICR_STATUSR registers are architecturally defined such
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that a write of a clear bit has no effect, whereas a write with a set bit
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clears that value. To allow userspace to freely set the values of these two
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registers, setting the attributes with the register offsets for these two
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registers simply sets the non-reserved bits to the value written.
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Accesses (reads and writes) to the GICD_ISPENDR register region and
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GICR_ISPENDR0 registers get/set the value of the latched pending state for
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the interrupts.
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This is identical to the value returned by a guest read from ISPENDR for an
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edge triggered interrupt, but may differ for level triggered interrupts.
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For edge triggered interrupts, once an interrupt becomes pending (whether
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because of an edge detected on the input line or because of a guest write
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to ISPENDR) this state is "latched", and only cleared when either the
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interrupt is activated or when the guest writes to ICPENDR. A level
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triggered interrupt may be pending either because the level input is held
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high by a device, or because of a guest write to the ISPENDR register. Only
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ISPENDR writes are latched; if the device lowers the line level then the
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interrupt is no longer pending unless the guest also wrote to ISPENDR, and
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conversely writes to ICPENDR or activations of the interrupt do not clear
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the pending status if the line level is still being held high. (These
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rules are documented in the GICv3 specification descriptions of the ICPENDR
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and ISPENDR registers.) For a level triggered interrupt the value accessed
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here is that of the latch which is set by ISPENDR and cleared by ICPENDR or
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interrupt activation, whereas the value returned by a guest read from
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ISPENDR is the logical OR of the latch value and the input line level.
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Raw access to the latch state is provided to userspace so that it can save
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and restore the entire GIC internal state (which is defined by the
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combination of the current input line level and the latch state, and cannot
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be deduced from purely the line level and the value of the ISPENDR
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registers).
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Accesses to GICD_ICPENDR register region and GICR_ICPENDR0 registers have
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RAZ/WI semantics, meaning that reads always return 0 and writes are always
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ignored.
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Errors:
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====== =====================================================
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-ENXIO Getting or setting this register is not yet supported
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-EBUSY One or more VCPUs are running
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====== =====================================================
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KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS
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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 .... 32 | 31 .... 16 | 15 .... 0 |
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values: | mpidr | RES | instr |
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The mpidr field encodes the CPU ID based on the affinity information in the
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architecture defined MPIDR, and the field is encoded as follows::
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| 63 .... 56 | 55 .... 48 | 47 .... 40 | 39 .... 32 |
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| Aff3 | Aff2 | Aff1 | Aff0 |
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The instr field encodes the system register to access based on the fields
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defined in the A64 instruction set encoding for system register access
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(RES means the bits are reserved for future use and should be zero)::
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| 15 ... 14 | 13 ... 11 | 10 ... 7 | 6 ... 3 | 2 ... 0 |
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| Op 0 | Op1 | CRn | CRm | Op2 |
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All system regs accessed through this API are (rw, 64-bit) and
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kvm_device_attr.addr points to a __u64 value.
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KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS accesses the CPU interface registers for the
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CPU specified by the mpidr field.
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CPU interface registers access is not implemented for AArch32 mode.
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Error -ENXIO is returned when accessed in AArch32 mode.
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Errors:
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======= =====================================================
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-ENXIO Getting or setting this register is not yet supported
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-EBUSY VCPU is running
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-EINVAL Invalid mpidr or register value supplied
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======= =====================================================
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KVM_DEV_ARM_VGIC_GRP_NR_IRQS
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Attributes:
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A value describing the number of interrupts (SGI, PPI and SPI) for
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this GIC instance, ranging from 64 to 1024, in increments of 32.
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kvm_device_attr.addr points to a __u32 value.
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Errors:
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======= ======================================
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-EINVAL Value set is out of the expected range
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-EBUSY Value has already be set.
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======= ======================================
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KVM_DEV_ARM_VGIC_GRP_CTRL
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Attributes:
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KVM_DEV_ARM_VGIC_CTRL_INIT
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request the initialization of the VGIC, no additional parameter in
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kvm_device_attr.addr.
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KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES
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save all LPI pending bits into guest RAM pending tables.
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The first kB of the pending table is not altered by this operation.
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Errors:
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======= ========================================================
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-ENXIO VGIC not properly configured as required prior to calling
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this attribute
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-ENODEV no online VCPU
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-ENOMEM memory shortage when allocating vgic internal data
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-EFAULT Invalid guest ram access
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-EBUSY One or more VCPUS are running
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======= ========================================================
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KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO
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Attributes:
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The attr field of kvm_device_attr encodes the following values::
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bits: | 63 .... 32 | 31 .... 10 | 9 .... 0 |
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values: | mpidr | info | vINTID |
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The vINTID specifies which set of IRQs is reported on.
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The info field specifies which information userspace wants to get or set
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using this interface. Currently we support the following info values:
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VGIC_LEVEL_INFO_LINE_LEVEL:
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Get/Set the input level of the IRQ line for a set of 32 contiguously
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numbered interrupts.
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vINTID must be a multiple of 32.
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kvm_device_attr.addr points to a __u32 value which will contain a
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bitmap where a set bit means the interrupt level is asserted.
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Bit[n] indicates the status for interrupt vINTID + n.
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SGIs and any interrupt with a higher ID than the number of interrupts
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supported, will be RAZ/WI. LPIs are always edge-triggered and are
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therefore not supported by this interface.
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PPIs are reported per VCPU as specified in the mpidr field, and SPIs are
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reported with the same value regardless of the mpidr specified.
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The mpidr field encodes the CPU ID based on the affinity information in the
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architecture defined MPIDR, and the field is encoded as follows::
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| 63 .... 56 | 55 .... 48 | 47 .... 40 | 39 .... 32 |
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| Aff3 | Aff2 | Aff1 | Aff0 |
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Errors:
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======= =============================================
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-EINVAL vINTID is not multiple of 32 or info field is
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not VGIC_LEVEL_INFO_LINE_LEVEL
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======= =============================================
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