GICV_AEOIR

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GICV_AEOIR, Virtual Machine Aliased End Of Interrupt Register

Purpose

A write to this register performs a priority drop for the specified Group 1 virtual interrupt and, if GICV_CTLR.EOImode == 0, also deactivates the interrupt.

Configuration

This register is present only when FEAT_GICv3_LEGACY is implemented and EL2 is implemented. Otherwise, direct accesses to GICV_AEOIR are RES0.

This register is available when the GIC implementation supports interrupt virtualization.

Attributes

Field descriptions

Bits [31:25]

INTID, bits [24:0]

The INTID of the signaled interrupt.

Note

INTIDs 1020-1023 are reserved and convey additional information such as spurious interrupts.

When affinity routing is not enabled:

Bits [23:13] are RES0.
For SGIs, bits [12:10] identify the CPU interface corresponding to the source PE. For all other interrupts these bits are RES0.

Additional information

A successful EOI request means that:

The highest priority bit in GICH_APR<n> is cleared, causing the running priority to drop.
If the appropriate GICV_CTLR.EOImode bit == 0, the interrupt is deactivated in the corresponding List register. If the INTID corresponds to a hardware interrupt, the interrupt is also deactivated in the Distributor.

Note

Only Group 1 interrupts can target the hypervisor, and therefore only Group 1 interrupts are deactivated in the Distributor.

A write to this register is UNPREDICTABLE if the INTID corresponds to a Group 0 interrupt. In addition, the following GICv2 UNPREDICTABLE cases require specific actions:

If highest active priority is Group 0 and the identified interrupt is in the List Registers and it matches the highest active priority. When EL2 is using System registers and ICH_VTR_EL2.SEIS is 1, an IMPLEMENTATION DEFINED SEI might be generated, otherwise GICv3 implementations must ignore such writes.
If the identified interrupt is in the List Registers, and the HW bit is 1, and the interrupt to be deactivated is an SGI (that is, the value of Physical_ID is between 0 and 15). GICv3 implementations must perform the deactivate operation. This means that a GICv3 implementation in legacy operation must ensure only a single SGI is active for a PE.
If the identified interrupt is in the List Registers, and the HW bit is 1, and the corresponding pINTID field value is between 1020 and 1023, indicating a special purpose INTID. GICv3 implementations must not perform a deactivate operation but must still change the state of the List register as appropriate. When EL2 is using System registers and ICH_VTR_EL2.SEIS is 1, an implementation might generate a system error.

Accessing GICV_AEOIR

This register is used only when System register access is not enabled. When System register access is enabled:

This register is used for Group 1 interrupts only. GICV_EOIR provides equivalent functionality for Group 0 interrupts.

When affinity routing is enabled, it is a programming error to use memory-mapped registers to access the GIC.

GICV_AEOIR can be accessed through the memory-mapped interfaces:

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
RES0							INTID