id = 2886
title = "ACPI MADT advertises GITS even when disabled"
state = "opened"
created_at = "2025-03-28T15:50:00.229Z"
closed_at = "n/a"
labels = ["ACPI", "target: arm", "workflow::Patch available"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/2886"
host-os = "Linux"
host-arch = "Host:x86 Guest:Arm"
qemu-version = "9.2.3"
guest-os = "Custom OS"
guest-arch = "Arm (aarch64)"
description = """As per the command line given above, QEMU shall emulate a GICv4 without GIC Interrupt Translation Service (GITS).

The following happens:
- ACPI **incorrectly** lists a GITS (type 0xf) structure in the MADT with GITS MMIO Base = 0x8080000
- The OS reads that structure and interprets it to mean a GITS is present at the given MMIO address
- Subsequent access to GITS MMIO causes a data abort (0x25) because QEMU doesn't emulate a GITS (as requested)

The bug is thus that QEMU wrongly advertises GITS as present (via the MADT) when it is in fact absent."""
reproduce = """1. Disable GITS emulation by passing `its=off` on the QEMU command line
2. Check if a GITS structure is listed in the ACPI MADT (must be present in ACPI MADT only if GITS is enabled and absent otherwise)"""
additional = """When booting with `its=on` (default), everything works as expected."""